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Change version to 1.1.9.
[pghintplan/pg_hint_plan.git] / pg_hint_plan.c
index 5800360..4f2fe1b 100644 (file)
@@ -4,15 +4,18 @@
  *               do instructions or hints to the planner using C-style block comments
  *               of the SQL.
  *
- * Copyright (c) 2012, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
+ * Copyright (c) 2012-2020, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
  *
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
+#include "catalog/pg_collation.h"
+#include "catalog/pg_index.h"
 #include "commands/prepare.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "nodes/nodeFuncs.h"
+#include "nodes/params.h"
 #include "optimizer/clauses.h"
 #include "optimizer/cost.h"
 #include "optimizer/geqo.h"
 #include "optimizer/planner.h"
 #include "optimizer/prep.h"
 #include "optimizer/restrictinfo.h"
+#include "parser/analyze.h"
 #include "parser/scansup.h"
 #include "tcop/utility.h"
+#include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
-#if PG_VERSION_NUM >= 90200
+#include "utils/rel.h"
+#include "utils/snapmgr.h"
+#include "utils/syscache.h"
+#include "utils/resowner.h"
+
 #include "catalog/pg_class.h"
-#endif
+
+#include "executor/spi.h"
+#include "catalog/pg_type.h"
+
+#include "plpgsql.h"
+
+/* partially copied from pg_stat_statements */
+#include "normalize_query.h"
+
+/* PostgreSQL */
+#include "access/htup_details.h"
 
 #ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
 #endif
 
-#if PG_VERSION_NUM < 90100
-#error unsupported PostgreSQL version
-#endif
-
 #define BLOCK_COMMENT_START            "/*"
 #define BLOCK_COMMENT_END              "*/"
 #define HINT_COMMENT_KEYWORD   "+"
@@ -48,16 +63,17 @@ PG_MODULE_MAGIC;
 /* hint keywords */
 #define HINT_SEQSCAN                   "SeqScan"
 #define HINT_INDEXSCAN                 "IndexScan"
+#define HINT_INDEXSCANREGEXP   "IndexScanRegexp"
 #define HINT_BITMAPSCAN                        "BitmapScan"
+#define HINT_BITMAPSCANREGEXP  "BitmapScanRegexp"
 #define HINT_TIDSCAN                   "TidScan"
 #define HINT_NOSEQSCAN                 "NoSeqScan"
 #define HINT_NOINDEXSCAN               "NoIndexScan"
 #define HINT_NOBITMAPSCAN              "NoBitmapScan"
 #define HINT_NOTIDSCAN                 "NoTidScan"
-#if PG_VERSION_NUM >= 90200
 #define HINT_INDEXONLYSCAN             "IndexOnlyScan"
+#define HINT_INDEXONLYSCANREGEXP       "IndexOnlyScanRegexp"
 #define HINT_NOINDEXONLYSCAN   "NoIndexOnlyScan"
-#endif
 #define HINT_NESTLOOP                  "NestLoop"
 #define HINT_MERGEJOIN                 "MergeJoin"
 #define HINT_HASHJOIN                  "HashJoin"
@@ -66,13 +82,17 @@ PG_MODULE_MAGIC;
 #define HINT_NOHASHJOIN                        "NoHashJoin"
 #define HINT_LEADING                   "Leading"
 #define HINT_SET                               "Set"
+#define HINT_ROWS                              "Rows"
 
 #define HINT_ARRAY_DEFAULT_INITSIZE 8
 
-#define hint_ereport(str, detail) \
-       ereport(pg_hint_plan_parse_messages, \
-                       (errmsg("hint syntax error at or near \"%s\"", (str)), \
-                        errdetail detail))
+#define hint_ereport(str, detail) hint_parse_ereport(str, detail)
+#define hint_parse_ereport(str, detail) \
+       do { \
+               ereport(pg_hint_plan_parse_message_level,               \
+                       (errmsg("pg_hint_plan: hint syntax error at or near \"%s\"", (str)), \
+                        errdetail detail)); \
+       } while(0)
 
 #define skip_space(str) \
        while (isspace(*str)) \
@@ -84,9 +104,7 @@ enum
        ENABLE_INDEXSCAN = 0x02,
        ENABLE_BITMAPSCAN = 0x04,
        ENABLE_TIDSCAN = 0x08,
-#if PG_VERSION_NUM >= 90200
        ENABLE_INDEXONLYSCAN = 0x10
-#endif
 } SCAN_TYPE_BITS;
 
 enum
@@ -96,14 +114,9 @@ enum
        ENABLE_HASHJOIN = 0x04
 } JOIN_TYPE_BITS;
 
-#if PG_VERSION_NUM >= 90200
 #define ENABLE_ALL_SCAN (ENABLE_SEQSCAN | ENABLE_INDEXSCAN | \
                                                 ENABLE_BITMAPSCAN | ENABLE_TIDSCAN | \
                                                 ENABLE_INDEXONLYSCAN)
-#else
-#define ENABLE_ALL_SCAN (ENABLE_SEQSCAN | ENABLE_INDEXSCAN | \
-                                                ENABLE_BITMAPSCAN | ENABLE_TIDSCAN)
-#endif
 #define ENABLE_ALL_JOIN (ENABLE_NESTLOOP | ENABLE_MERGEJOIN | ENABLE_HASHJOIN)
 #define DISABLE_ALL_SCAN 0
 #define DISABLE_ALL_JOIN 0
@@ -113,16 +126,17 @@ typedef enum HintKeyword
 {
        HINT_KEYWORD_SEQSCAN,
        HINT_KEYWORD_INDEXSCAN,
+       HINT_KEYWORD_INDEXSCANREGEXP,
        HINT_KEYWORD_BITMAPSCAN,
+       HINT_KEYWORD_BITMAPSCANREGEXP,
        HINT_KEYWORD_TIDSCAN,
        HINT_KEYWORD_NOSEQSCAN,
        HINT_KEYWORD_NOINDEXSCAN,
        HINT_KEYWORD_NOBITMAPSCAN,
        HINT_KEYWORD_NOTIDSCAN,
-#if PG_VERSION_NUM >= 90200
        HINT_KEYWORD_INDEXONLYSCAN,
+       HINT_KEYWORD_INDEXONLYSCANREGEXP,
        HINT_KEYWORD_NOINDEXONLYSCAN,
-#endif
        HINT_KEYWORD_NESTLOOP,
        HINT_KEYWORD_MERGEJOIN,
        HINT_KEYWORD_HASHJOIN,
@@ -131,6 +145,7 @@ typedef enum HintKeyword
        HINT_KEYWORD_NOHASHJOIN,
        HINT_KEYWORD_LEADING,
        HINT_KEYWORD_SET,
+       HINT_KEYWORD_ROWS,
        HINT_KEYWORD_UNRECOGNIZED
 } HintKeyword;
 
@@ -141,26 +156,28 @@ typedef Hint *(*HintCreateFunction) (const char *hint_str,
                                                                         const char *keyword,
                                                                         HintKeyword hint_keyword);
 typedef void (*HintDeleteFunction) (Hint *hint);
-typedef void (*HintDumpFunction) (Hint *hint, StringInfo buf);
+typedef void (*HintDescFunction) (Hint *hint, StringInfo buf, bool nolf);
 typedef int (*HintCmpFunction) (const Hint *a, const Hint *b);
 typedef const char *(*HintParseFunction) (Hint *hint, HintState *hstate,
                                                                                  Query *parse, const char *str);
 
 /* hint types */
-#define NUM_HINT_TYPE  4
+#define NUM_HINT_TYPE  5
 typedef enum HintType
 {
        HINT_TYPE_SCAN_METHOD,
        HINT_TYPE_JOIN_METHOD,
        HINT_TYPE_LEADING,
-       HINT_TYPE_SET
+       HINT_TYPE_SET,
+       HINT_TYPE_ROWS,
 } HintType;
 
 static const char *HintTypeName[] = {
        "scan method",
        "join method",
        "leading",
-       "set"
+       "set",
+       "rows",
 };
 
 /* hint status */
@@ -176,6 +193,19 @@ typedef enum HintStatus
 #define hint_state_enabled(hint) ((hint)->base.state == HINT_STATE_NOTUSED || \
                                                                  (hint)->base.state == HINT_STATE_USED)
 
+static unsigned int qno = 0;
+static unsigned int msgqno = 0;
+static char qnostr[32];
+static const char *current_hint_str = NULL;
+
+/*
+ * However we usually take a hint stirng in post_parse_analyze_hook, we still
+ * need to do so in planner_hook when client starts query execution from the
+ * bind message on a prepared query. This variable prevent duplicate and
+ * sometimes harmful hint string retrieval.
+ */
+static bool current_hint_retrieved = false;
+
 /* common data for all hints. */
 struct Hint
 {
@@ -185,7 +215,7 @@ struct Hint
        HintType                        type;
        HintStatus                      state;
        HintDeleteFunction      delete_func;
-       HintDumpFunction        dump_func;
+       HintDescFunction        desc_func;
        HintCmpFunction         cmp_func;
        HintParseFunction       parse_func;
 };
@@ -196,24 +226,46 @@ typedef struct ScanMethodHint
        Hint                    base;
        char               *relname;
        List               *indexnames;
+       bool                    regexp;
        unsigned char   enforce_mask;
 } ScanMethodHint;
 
+typedef struct ParentIndexInfo
+{
+       bool            indisunique;
+       Oid                     method;
+       List       *column_names;
+       char       *expression_str;
+       Oid                *indcollation;
+       Oid                *opclass;
+       int16      *indoption;
+       char       *indpred_str;
+} ParentIndexInfo;
+
 /* join method hints */
 typedef struct JoinMethodHint
 {
        Hint                    base;
        int                             nrels;
+       int                             inner_nrels;
        char              **relnames;
        unsigned char   enforce_mask;
        Relids                  joinrelids;
+       Relids                  inner_joinrelids;
 } JoinMethodHint;
 
 /* join order hints */
+typedef struct OuterInnerRels
+{
+       char   *relation;
+       List   *outer_inner_pair;
+} OuterInnerRels;
+
 typedef struct LeadingHint
 {
-       Hint    base;
-       List   *relations;              /* relation names specified in Leading hint */
+       Hint                    base;
+       List               *relations;  /* relation names specified in Leading hint */
+       OuterInnerRels *outer_inner;
 } LeadingHint;
 
 /* change a run-time parameter hints */
@@ -225,6 +277,26 @@ typedef struct SetHint
        List   *words;
 } SetHint;
 
+/* rows hints */
+typedef enum RowsValueType {
+       RVT_ABSOLUTE,           /* Rows(... #1000) */
+       RVT_ADD,                        /* Rows(... +1000) */
+       RVT_SUB,                        /* Rows(... -1000) */
+       RVT_MULTI,                      /* Rows(... *1.2) */
+} RowsValueType;
+typedef struct RowsHint
+{
+       Hint                    base;
+       int                             nrels;
+       int                             inner_nrels;
+       char              **relnames;
+       Relids                  joinrelids;
+       Relids                  inner_joinrelids;
+       char               *rows_str;
+       RowsValueType   value_type;
+       double                  rows;
+} RowsHint;
+
 /*
  * Describes a context of hint processing.
  */
@@ -243,8 +315,11 @@ struct HintState
        /* for scan method hints */
        ScanMethodHint **scan_hints;            /* parsed scan hints */
        int                             init_scan_mask;         /* initial value scan parameter */
+       PlannerInfo        *current_root;               /* PlannerInfo for the followings */
        Index                   parent_relid;           /* inherit parent table relid */
        ScanMethodHint *parent_hint;            /* inherit parent table scan hint */
+       List               *parent_index_infos; /* information of inherit parent table's
+                                                                                * index */
 
        /* for join method hints */
        JoinMethodHint **join_hints;            /* parsed join hints */
@@ -252,11 +327,14 @@ struct HintState
        List              **join_hint_level;
 
        /* for Leading hint */
-       LeadingHint        *leading_hint;               /* parsed last specified Leading hint */
+       LeadingHint       **leading_hint;               /* parsed Leading hints */
 
        /* for Set hints */
        SetHint           **set_hints;                  /* parsed Set hints */
        GucContext              context;                        /* which GUC parameters can we set? */
+
+       /* for Rows hints */
+       RowsHint          **rows_hints;                 /* parsed Rows hints */
 };
 
 /*
@@ -276,11 +354,11 @@ void              _PG_fini(void);
 static void push_hint(HintState *hstate);
 static void pop_hint(void);
 
+static void pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query);
 static void pg_hint_plan_ProcessUtility(Node *parsetree,
-                                                                               const char *queryString,
-                                                                               ParamListInfo params, bool isTopLevel,
-                                                                               DestReceiver *dest,
-                                                                               char *completionTag);
+                                       const char *queryString,
+                                       ProcessUtilityContext context, ParamListInfo params,
+                                       DestReceiver *dest, char *completionTag);
 static PlannedStmt *pg_hint_plan_planner(Query *parse, int cursorOptions,
                                                                                 ParamListInfo boundParams);
 static void pg_hint_plan_get_relation_info(PlannerInfo *root,
@@ -293,31 +371,45 @@ static RelOptInfo *pg_hint_plan_join_search(PlannerInfo *root,
 static Hint *ScanMethodHintCreate(const char *hint_str, const char *keyword,
                                                                  HintKeyword hint_keyword);
 static void ScanMethodHintDelete(ScanMethodHint *hint);
-static void ScanMethodHintDump(ScanMethodHint *hint, StringInfo buf);
+static void ScanMethodHintDesc(ScanMethodHint *hint, StringInfo buf, bool nolf);
 static int ScanMethodHintCmp(const ScanMethodHint *a, const ScanMethodHint *b);
 static const char *ScanMethodHintParse(ScanMethodHint *hint, HintState *hstate,
                                                                           Query *parse, const char *str);
 static Hint *JoinMethodHintCreate(const char *hint_str, const char *keyword,
                                                                  HintKeyword hint_keyword);
 static void JoinMethodHintDelete(JoinMethodHint *hint);
-static void JoinMethodHintDump(JoinMethodHint *hint, StringInfo buf);
+static void JoinMethodHintDesc(JoinMethodHint *hint, StringInfo buf, bool nolf);
 static int JoinMethodHintCmp(const JoinMethodHint *a, const JoinMethodHint *b);
 static const char *JoinMethodHintParse(JoinMethodHint *hint, HintState *hstate,
                                                                           Query *parse, const char *str);
 static Hint *LeadingHintCreate(const char *hint_str, const char *keyword,
                                                           HintKeyword hint_keyword);
 static void LeadingHintDelete(LeadingHint *hint);
-static void LeadingHintDump(LeadingHint *hint, StringInfo buf);
+static void LeadingHintDesc(LeadingHint *hint, StringInfo buf, bool nolf);
 static int LeadingHintCmp(const LeadingHint *a, const LeadingHint *b);
 static const char *LeadingHintParse(LeadingHint *hint, HintState *hstate,
                                                                        Query *parse, const char *str);
 static Hint *SetHintCreate(const char *hint_str, const char *keyword,
                                                   HintKeyword hint_keyword);
 static void SetHintDelete(SetHint *hint);
-static void SetHintDump(SetHint *hint, StringInfo buf);
+static void SetHintDesc(SetHint *hint, StringInfo buf, bool nolf);
 static int SetHintCmp(const SetHint *a, const SetHint *b);
 static const char *SetHintParse(SetHint *hint, HintState *hstate, Query *parse,
                                                                const char *str);
+static Hint *RowsHintCreate(const char *hint_str, const char *keyword,
+                                                       HintKeyword hint_keyword);
+static void RowsHintDelete(RowsHint *hint);
+static void RowsHintDesc(RowsHint *hint, StringInfo buf, bool nolf);
+static int RowsHintCmp(const RowsHint *a, const RowsHint *b);
+static const char *RowsHintParse(RowsHint *hint, HintState *hstate,
+                                                                Query *parse, const char *str);
+static Hint *LeadingHintCreate(const char *hint_str, const char *keyword,
+                                                          HintKeyword hint_keyword);
+
+static void quote_value(StringInfo buf, const char *value);
+
+static const char *parse_quoted_value(const char *str, char **word,
+                                                                         bool truncate);
 
 RelOptInfo *pg_hint_plan_standard_join_search(PlannerInfo *root,
                                                                                          int levels_needed,
@@ -331,22 +423,37 @@ static void make_rels_by_clauseless_joins(PlannerInfo *root,
 static bool has_join_restriction(PlannerInfo *root, RelOptInfo *rel);
 static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
                                                                        Index rti, RangeTblEntry *rte);
-#if PG_VERSION_NUM >= 90200
 static void generate_mergeappend_paths(PlannerInfo *root, RelOptInfo *rel,
                                                   List *live_childrels,
                                                   List *all_child_pathkeys);
-#endif
+static Path *get_cheapest_parameterized_child_path(PlannerInfo *root,
+                                                                         RelOptInfo *rel,
+                                                                         Relids required_outer);
 static List *accumulate_append_subpath(List *subpaths, Path *path);
-#if PG_VERSION_NUM < 90200
-static void set_dummy_rel_pathlist(RelOptInfo *rel);
-#endif
 RelOptInfo *pg_hint_plan_make_join_rel(PlannerInfo *root, RelOptInfo *rel1,
                                                                           RelOptInfo *rel2);
 
+static void pg_hint_plan_plpgsql_stmt_beg(PLpgSQL_execstate *estate,
+                                                                                 PLpgSQL_stmt *stmt);
+static void pg_hint_plan_plpgsql_stmt_end(PLpgSQL_execstate *estate,
+                                                                                 PLpgSQL_stmt *stmt);
+static void plpgsql_query_erase_callback(ResourceReleasePhase phase,
+                                                                                bool isCommit,
+                                                                                bool isTopLevel,
+                                                                                void *arg);
+
 /* GUC variables */
 static bool    pg_hint_plan_enable_hint = true;
-static bool    pg_hint_plan_debug_print = false;
-static int     pg_hint_plan_parse_messages = INFO;
+static int debug_level = 0;
+static int     pg_hint_plan_parse_message_level = INFO;
+static int     pg_hint_plan_debug_message_level = LOG;
+/* Default is off, to keep backward compatibility. */
+static bool    pg_hint_plan_enable_hint_table = false;
+
+static int plpgsql_recurse_level = 0;          /* PLpgSQL recursion level            */
+static int recurse_level = 0;          /* recursion level incl. direct SPI calls */
+static int hint_inhibit_level = 0;                     /* Inhibit hinting if this is above 0 */
+                                                                                       /* (This could not be above 1)        */
 
 static const struct config_enum_entry parse_messages_level_options[] = {
        {"debug", DEBUG2, true},
@@ -367,11 +474,28 @@ static const struct config_enum_entry parse_messages_level_options[] = {
        {NULL, 0, false}
 };
 
+static const struct config_enum_entry parse_debug_level_options[] = {
+       {"off", 0, false},
+       {"on", 1, false},
+       {"detailed", 2, false},
+       {"verbose", 3, false},
+       {"0", 0, true},
+       {"1", 1, true},
+       {"2", 2, true},
+       {"3", 3, true},
+       {"no", 0, true},
+       {"yes", 1, true},
+       {"false", 0, true},
+       {"true", 1, true},
+       {NULL, 0, false}
+};
+
 /* Saved hook values in case of unload */
-static ProcessUtility_hook_type prev_ProcessUtility = NULL;
+static post_parse_analyze_hook_type prev_post_parse_analyze_hook = NULL;
 static planner_hook_type prev_planner = NULL;
 static get_relation_info_hook_type prev_get_relation_info = NULL;
 static join_search_hook_type prev_join_search = NULL;
+static ProcessUtility_hook_type prev_ProcessUtility_hook = NULL;
 
 /* Hold reference to currently active hint */
 static HintState *current_hint = NULL;
@@ -382,25 +506,22 @@ static HintState *current_hint = NULL;
  */
 static List *HintStateStack = NIL;
 
-/*
- * Holds statement name during executing EXECUTE command.  NULL for other
- * statements.
- */
-static char       *stmt_name = NULL;
-
 static const HintParser parsers[] = {
        {HINT_SEQSCAN, ScanMethodHintCreate, HINT_KEYWORD_SEQSCAN},
        {HINT_INDEXSCAN, ScanMethodHintCreate, HINT_KEYWORD_INDEXSCAN},
+       {HINT_INDEXSCANREGEXP, ScanMethodHintCreate, HINT_KEYWORD_INDEXSCANREGEXP},
        {HINT_BITMAPSCAN, ScanMethodHintCreate, HINT_KEYWORD_BITMAPSCAN},
+       {HINT_BITMAPSCANREGEXP, ScanMethodHintCreate,
+        HINT_KEYWORD_BITMAPSCANREGEXP},
        {HINT_TIDSCAN, ScanMethodHintCreate, HINT_KEYWORD_TIDSCAN},
        {HINT_NOSEQSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOSEQSCAN},
        {HINT_NOINDEXSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOINDEXSCAN},
        {HINT_NOBITMAPSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOBITMAPSCAN},
        {HINT_NOTIDSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOTIDSCAN},
-#if PG_VERSION_NUM >= 90200
        {HINT_INDEXONLYSCAN, ScanMethodHintCreate, HINT_KEYWORD_INDEXONLYSCAN},
+       {HINT_INDEXONLYSCANREGEXP, ScanMethodHintCreate,
+        HINT_KEYWORD_INDEXONLYSCANREGEXP},
        {HINT_NOINDEXONLYSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOINDEXONLYSCAN},
-#endif
        {HINT_NESTLOOP, JoinMethodHintCreate, HINT_KEYWORD_NESTLOOP},
        {HINT_MERGEJOIN, JoinMethodHintCreate, HINT_KEYWORD_MERGEJOIN},
        {HINT_HASHJOIN, JoinMethodHintCreate, HINT_KEYWORD_HASHJOIN},
@@ -409,32 +530,46 @@ static const HintParser parsers[] = {
        {HINT_NOHASHJOIN, JoinMethodHintCreate, HINT_KEYWORD_NOHASHJOIN},
        {HINT_LEADING, LeadingHintCreate, HINT_KEYWORD_LEADING},
        {HINT_SET, SetHintCreate, HINT_KEYWORD_SET},
+       {HINT_ROWS, RowsHintCreate, HINT_KEYWORD_ROWS},
        {NULL, NULL, HINT_KEYWORD_UNRECOGNIZED}
 };
 
+PLpgSQL_plugin  plugin_funcs = {
+       NULL,
+       NULL,
+       NULL,
+       pg_hint_plan_plpgsql_stmt_beg,
+       pg_hint_plan_plpgsql_stmt_end,
+       NULL,
+       NULL,
+};
+
 /*
  * Module load callbacks
  */
 void
 _PG_init(void)
 {
+       PLpgSQL_plugin  **var_ptr;
+
        /* Define custom GUC variables. */
        DefineCustomBoolVariable("pg_hint_plan.enable_hint",
                         "Force planner to use plans specified in the hint comment preceding to the query.",
                                                         NULL,
                                                         &pg_hint_plan_enable_hint,
                                                         true,
-                                                        PGC_USERSET,
+                                                    PGC_USERSET,
                                                         0,
                                                         NULL,
                                                         NULL,
                                                         NULL);
 
-       DefineCustomBoolVariable("pg_hint_plan.debug_print",
+       DefineCustomEnumVariable("pg_hint_plan.debug_print",
                                                         "Logs results of hint parsing.",
                                                         NULL,
-                                                        &pg_hint_plan_debug_print,
+                                                        &debug_level,
                                                         false,
+                                                        parse_debug_level_options,
                                                         PGC_USERSET,
                                                         0,
                                                         NULL,
@@ -444,7 +579,7 @@ _PG_init(void)
        DefineCustomEnumVariable("pg_hint_plan.parse_messages",
                                                         "Message level of parse errors.",
                                                         NULL,
-                                                        &pg_hint_plan_parse_messages,
+                                                        &pg_hint_plan_parse_message_level,
                                                         INFO,
                                                         parse_messages_level_options,
                                                         PGC_USERSET,
@@ -453,15 +588,46 @@ _PG_init(void)
                                                         NULL,
                                                         NULL);
 
+       DefineCustomEnumVariable("pg_hint_plan.message_level",
+                                                        "Message level of debug messages.",
+                                                        NULL,
+                                                        &pg_hint_plan_debug_message_level,
+                                                        LOG,
+                                                        parse_messages_level_options,
+                                                        PGC_USERSET,
+                                                        0,
+                                                        NULL,
+                                                        NULL,
+                                                        NULL);
+
+       DefineCustomBoolVariable("pg_hint_plan.enable_hint_table",
+                                        "Force planner to not get hint by using table lookups.",
+                                                        NULL,
+                                                        &pg_hint_plan_enable_hint_table,
+                                                        false,
+                                                        PGC_USERSET,
+                                                        0,
+                                                        NULL,
+                                                        NULL,
+                                                        NULL);
+
        /* Install hooks. */
-       prev_ProcessUtility = ProcessUtility_hook;
-       ProcessUtility_hook = pg_hint_plan_ProcessUtility;
+       prev_post_parse_analyze_hook = post_parse_analyze_hook;
+       post_parse_analyze_hook = pg_hint_plan_post_parse_analyze;
        prev_planner = planner_hook;
        planner_hook = pg_hint_plan_planner;
        prev_get_relation_info = get_relation_info_hook;
        get_relation_info_hook = pg_hint_plan_get_relation_info;
        prev_join_search = join_search_hook;
        join_search_hook = pg_hint_plan_join_search;
+       prev_ProcessUtility_hook = ProcessUtility_hook;
+       ProcessUtility_hook = pg_hint_plan_ProcessUtility;
+
+       /* setup PL/pgSQL plugin hook */
+       var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
+       *var_ptr = &plugin_funcs;
+
+       RegisterResourceReleaseCallback(plpgsql_query_erase_callback, NULL);
 }
 
 /*
@@ -471,11 +637,18 @@ _PG_init(void)
 void
 _PG_fini(void)
 {
+       PLpgSQL_plugin  **var_ptr;
+
        /* Uninstall hooks. */
-       ProcessUtility_hook = prev_ProcessUtility;
+       post_parse_analyze_hook = prev_post_parse_analyze_hook;
        planner_hook = prev_planner;
        get_relation_info_hook = prev_get_relation_info;
        join_search_hook = prev_join_search;
+       ProcessUtility_hook = prev_ProcessUtility_hook;
+
+       /* uninstall PL/pgSQL plugin hook */
+       var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
+       *var_ptr = NULL;
 }
 
 /*
@@ -495,11 +668,12 @@ ScanMethodHintCreate(const char *hint_str, const char *keyword,
        hint->base.type = HINT_TYPE_SCAN_METHOD;
        hint->base.state = HINT_STATE_NOTUSED;
        hint->base.delete_func = (HintDeleteFunction) ScanMethodHintDelete;
-       hint->base.dump_func = (HintDumpFunction) ScanMethodHintDump;
+       hint->base.desc_func = (HintDescFunction) ScanMethodHintDesc;
        hint->base.cmp_func = (HintCmpFunction) ScanMethodHintCmp;
        hint->base.parse_func = (HintParseFunction) ScanMethodHintParse;
        hint->relname = NULL;
        hint->indexnames = NIL;
+       hint->regexp = false;
        hint->enforce_mask = 0;
 
        return (Hint *) hint;
@@ -530,13 +704,15 @@ JoinMethodHintCreate(const char *hint_str, const char *keyword,
        hint->base.type = HINT_TYPE_JOIN_METHOD;
        hint->base.state = HINT_STATE_NOTUSED;
        hint->base.delete_func = (HintDeleteFunction) JoinMethodHintDelete;
-       hint->base.dump_func = (HintDumpFunction) JoinMethodHintDump;
+       hint->base.desc_func = (HintDescFunction) JoinMethodHintDesc;
        hint->base.cmp_func = (HintCmpFunction) JoinMethodHintCmp;
        hint->base.parse_func = (HintParseFunction) JoinMethodHintParse;
        hint->nrels = 0;
+       hint->inner_nrels = 0;
        hint->relnames = NULL;
        hint->enforce_mask = 0;
        hint->joinrelids = NULL;
+       hint->inner_joinrelids = NULL;
 
        return (Hint *) hint;
 }
@@ -555,7 +731,9 @@ JoinMethodHintDelete(JoinMethodHint *hint)
                        pfree(hint->relnames[i]);
                pfree(hint->relnames);
        }
+
        bms_free(hint->joinrelids);
+       bms_free(hint->inner_joinrelids);
        pfree(hint);
 }
 
@@ -572,10 +750,11 @@ LeadingHintCreate(const char *hint_str, const char *keyword,
        hint->base.type = HINT_TYPE_LEADING;
        hint->base.state = HINT_STATE_NOTUSED;
        hint->base.delete_func = (HintDeleteFunction)LeadingHintDelete;
-       hint->base.dump_func = (HintDumpFunction) LeadingHintDump;
+       hint->base.desc_func = (HintDescFunction) LeadingHintDesc;
        hint->base.cmp_func = (HintCmpFunction) LeadingHintCmp;
        hint->base.parse_func = (HintParseFunction) LeadingHintParse;
        hint->relations = NIL;
+       hint->outer_inner = NULL;
 
        return (Hint *) hint;
 }
@@ -587,6 +766,8 @@ LeadingHintDelete(LeadingHint *hint)
                return;
 
        list_free_deep(hint->relations);
+       if (hint->outer_inner)
+               pfree(hint->outer_inner);
        pfree(hint);
 }
 
@@ -603,7 +784,7 @@ SetHintCreate(const char *hint_str, const char *keyword,
        hint->base.type = HINT_TYPE_SET;
        hint->base.state = HINT_STATE_NOTUSED;
        hint->base.delete_func = (HintDeleteFunction) SetHintDelete;
-       hint->base.dump_func = (HintDumpFunction) SetHintDump;
+       hint->base.desc_func = (HintDescFunction) SetHintDesc;
        hint->base.cmp_func = (HintCmpFunction) SetHintCmp;
        hint->base.parse_func = (HintParseFunction) SetHintParse;
        hint->name = NULL;
@@ -628,6 +809,54 @@ SetHintDelete(SetHint *hint)
        pfree(hint);
 }
 
+static Hint *
+RowsHintCreate(const char *hint_str, const char *keyword,
+                          HintKeyword hint_keyword)
+{
+       RowsHint *hint;
+
+       hint = palloc(sizeof(RowsHint));
+       hint->base.hint_str = hint_str;
+       hint->base.keyword = keyword;
+       hint->base.hint_keyword = hint_keyword;
+       hint->base.type = HINT_TYPE_ROWS;
+       hint->base.state = HINT_STATE_NOTUSED;
+       hint->base.delete_func = (HintDeleteFunction) RowsHintDelete;
+       hint->base.desc_func = (HintDescFunction) RowsHintDesc;
+       hint->base.cmp_func = (HintCmpFunction) RowsHintCmp;
+       hint->base.parse_func = (HintParseFunction) RowsHintParse;
+       hint->nrels = 0;
+       hint->inner_nrels = 0;
+       hint->relnames = NULL;
+       hint->joinrelids = NULL;
+       hint->inner_joinrelids = NULL;
+       hint->rows_str = NULL;
+       hint->value_type = RVT_ABSOLUTE;
+       hint->rows = 0;
+
+       return (Hint *) hint;
+}
+
+static void
+RowsHintDelete(RowsHint *hint)
+{
+       if (!hint)
+               return;
+
+       if (hint->relnames)
+       {
+               int     i;
+
+               for (i = 0; i < hint->nrels; i++)
+                       pfree(hint->relnames[i]);
+               pfree(hint->relnames);
+       }
+
+       bms_free(hint->joinrelids);
+       bms_free(hint->inner_joinrelids);
+       pfree(hint);
+}
+
 static HintState *
 HintStateCreate(void)
 {
@@ -641,14 +870,17 @@ HintStateCreate(void)
        memset(hstate->num_hints, 0, sizeof(hstate->num_hints));
        hstate->scan_hints = NULL;
        hstate->init_scan_mask = 0;
+       hstate->current_root = NULL;
        hstate->parent_relid = 0;
        hstate->parent_hint = NULL;
+       hstate->parent_index_infos = NIL;
        hstate->join_hints = NULL;
        hstate->init_join_mask = 0;
        hstate->join_hint_level = NULL;
        hstate->leading_hint = NULL;
        hstate->context = superuser() ? PGC_SUSET : PGC_USERSET;
        hstate->set_hints = NULL;
+       hstate->rows_hints = NULL;
 
        return hstate;
 }
@@ -668,21 +900,22 @@ HintStateDelete(HintState *hstate)
                hstate->all_hints[i]->delete_func(hstate->all_hints[i]);
        if (hstate->all_hints)
                pfree(hstate->all_hints);
+       if (hstate->parent_index_infos)
+               list_free(hstate->parent_index_infos);
 }
 
 /*
- * dump functions
+ * Copy given value into buf, with quoting with '"' if necessary.
  */
-
 static void
-dump_quote_value(StringInfo buf, const char *value)
+quote_value(StringInfo buf, const char *value)
 {
        bool            need_quote = false;
        const char *str;
 
        for (str = value; *str != '\0'; str++)
        {
-               if (isspace(*str) || *str == ')' || *str == '"')
+               if (isspace(*str) || *str == '(' || *str == ')' || *str == '"')
                {
                        need_quote = true;
                        appendStringInfoCharMacro(buf, '"');
@@ -703,65 +936,103 @@ dump_quote_value(StringInfo buf, const char *value)
 }
 
 static void
-ScanMethodHintDump(ScanMethodHint *hint, StringInfo buf)
+ScanMethodHintDesc(ScanMethodHint *hint, StringInfo buf, bool nolf)
 {
        ListCell   *l;
 
        appendStringInfo(buf, "%s(", hint->base.keyword);
        if (hint->relname != NULL)
        {
-               dump_quote_value(buf, hint->relname);
+               quote_value(buf, hint->relname);
                foreach(l, hint->indexnames)
                {
                        appendStringInfoCharMacro(buf, ' ');
-                       dump_quote_value(buf, (char *) lfirst(l));
+                       quote_value(buf, (char *) lfirst(l));
                }
        }
-       appendStringInfoString(buf, ")\n");
+       appendStringInfoString(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
 }
 
 static void
-JoinMethodHintDump(JoinMethodHint *hint, StringInfo buf)
+JoinMethodHintDesc(JoinMethodHint *hint, StringInfo buf, bool nolf)
 {
        int     i;
 
        appendStringInfo(buf, "%s(", hint->base.keyword);
        if (hint->relnames != NULL)
        {
-               dump_quote_value(buf, hint->relnames[0]);
+               quote_value(buf, hint->relnames[0]);
                for (i = 1; i < hint->nrels; i++)
                {
                        appendStringInfoCharMacro(buf, ' ');
-                       dump_quote_value(buf, hint->relnames[i]);
+                       quote_value(buf, hint->relnames[i]);
                }
        }
-       appendStringInfoString(buf, ")\n");
-
+       appendStringInfoString(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
 }
 
 static void
-LeadingHintDump(LeadingHint *hint, StringInfo buf)
+OuterInnerDesc(OuterInnerRels *outer_inner, StringInfo buf)
 {
-       bool            is_first;
-       ListCell   *l;
+       if (outer_inner->relation == NULL)
+       {
+               bool            is_first;
+               ListCell   *l;
+
+               is_first = true;
+
+               appendStringInfoCharMacro(buf, '(');
+               foreach(l, outer_inner->outer_inner_pair)
+               {
+                       if (is_first)
+                               is_first = false;
+                       else
+                               appendStringInfoCharMacro(buf, ' ');
+
+                       OuterInnerDesc(lfirst(l), buf);
+               }
+
+               appendStringInfoCharMacro(buf, ')');
+       }
+       else
+               quote_value(buf, outer_inner->relation);
+}
 
+static void
+LeadingHintDesc(LeadingHint *hint, StringInfo buf, bool nolf)
+{
        appendStringInfo(buf, "%s(", HINT_LEADING);
-       is_first = true;
-       foreach(l, hint->relations)
+       if (hint->outer_inner == NULL)
        {
-               if (is_first)
-                       is_first = false;
-               else
-                       appendStringInfoCharMacro(buf, ' ');
+               ListCell   *l;
+               bool            is_first;
+
+               is_first = true;
+
+               foreach(l, hint->relations)
+               {
+                       if (is_first)
+                               is_first = false;
+                       else
+                               appendStringInfoCharMacro(buf, ' ');
 
-               dump_quote_value(buf, (char *) lfirst(l));
+                       quote_value(buf, (char *) lfirst(l));
+               }
        }
+       else
+               OuterInnerDesc(hint->outer_inner, buf);
 
-       appendStringInfoString(buf, ")\n");
+       appendStringInfoString(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
 }
 
 static void
-SetHintDump(SetHint *hint, StringInfo buf)
+SetHintDesc(SetHint *hint, StringInfo buf, bool nolf)
 {
        bool            is_first = true;
        ListCell   *l;
@@ -774,27 +1045,66 @@ SetHintDump(SetHint *hint, StringInfo buf)
                else
                        appendStringInfoCharMacro(buf, ' ');
 
-               dump_quote_value(buf, (char *) lfirst(l));
+               quote_value(buf, (char *) lfirst(l));
        }
-       appendStringInfo(buf, ")\n");
+       appendStringInfo(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
 }
 
 static void
-all_hint_dump(HintState *hstate, StringInfo buf, const char *title,
-                         HintStatus state)
+RowsHintDesc(RowsHint *hint, StringInfo buf, bool nolf)
 {
        int     i;
 
-       appendStringInfo(buf, "%s:\n", title);
+       appendStringInfo(buf, "%s(", hint->base.keyword);
+       if (hint->relnames != NULL)
+       {
+               quote_value(buf, hint->relnames[0]);
+               for (i = 1; i < hint->nrels; i++)
+               {
+                       appendStringInfoCharMacro(buf, ' ');
+                       quote_value(buf, hint->relnames[i]);
+               }
+       }
+       if (hint->rows_str != NULL)
+               appendStringInfo(buf, " %s", hint->rows_str);
+       appendStringInfoString(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
+}
+
+/*
+ * Append string which represents all hints in a given state to buf, with
+ * preceding title with them.
+ */
+static void
+desc_hint_in_state(HintState *hstate, StringInfo buf, const char *title,
+                                  HintStatus state, bool nolf)
+{
+       int     i, nshown;
+
+       appendStringInfo(buf, "%s:", title);
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
+
+       nshown = 0;
        for (i = 0; i < hstate->nall_hints; i++)
        {
                if (hstate->all_hints[i]->state != state)
                        continue;
 
-               hstate->all_hints[i]->dump_func(hstate->all_hints[i], buf);
+               hstate->all_hints[i]->desc_func(hstate->all_hints[i], buf, nolf);
+               nshown++;
        }
+
+       if (nolf && nshown == 0)
+               appendStringInfoString(buf, "(none)");
 }
 
+/*
+ * Dump contents of given hstate to server log with log level LOG.
+ */
 static void
 HintStateDump(HintState *hstate)
 {
@@ -802,19 +1112,48 @@ HintStateDump(HintState *hstate)
 
        if (!hstate)
        {
-               elog(LOG, "pg_hint_plan:\nno hint");
+               elog(pg_hint_plan_debug_message_level, "pg_hint_plan:\nno hint");
                return;
        }
 
        initStringInfo(&buf);
 
        appendStringInfoString(&buf, "pg_hint_plan:\n");
-       all_hint_dump(hstate, &buf, "used hint", HINT_STATE_USED);
-       all_hint_dump(hstate, &buf, "not used hint", HINT_STATE_NOTUSED);
-       all_hint_dump(hstate, &buf, "duplication hint", HINT_STATE_DUPLICATION);
-       all_hint_dump(hstate, &buf, "error hint", HINT_STATE_ERROR);
+       desc_hint_in_state(hstate, &buf, "used hint", HINT_STATE_USED, false);
+       desc_hint_in_state(hstate, &buf, "not used hint", HINT_STATE_NOTUSED, false);
+       desc_hint_in_state(hstate, &buf, "duplication hint", HINT_STATE_DUPLICATION, false);
+       desc_hint_in_state(hstate, &buf, "error hint", HINT_STATE_ERROR, false);
+
+       ereport(pg_hint_plan_debug_message_level,
+                       (errmsg ("%s", buf.data)));
+
+       pfree(buf.data);
+}
+
+static void
+HintStateDump2(HintState *hstate)
+{
+       StringInfoData  buf;
+
+       if (!hstate)
+       {
+               elog(pg_hint_plan_debug_message_level,
+                        "pg_hint_plan%s: HintStateDump: no hint", qnostr);
+               return;
+       }
 
-       elog(LOG, "%s", buf.data);
+       initStringInfo(&buf);
+       appendStringInfo(&buf, "pg_hint_plan%s: HintStateDump: ", qnostr);
+       desc_hint_in_state(hstate, &buf, "{used hints", HINT_STATE_USED, true);
+       desc_hint_in_state(hstate, &buf, "}, {not used hints", HINT_STATE_NOTUSED, true);
+       desc_hint_in_state(hstate, &buf, "}, {duplicate hints", HINT_STATE_DUPLICATION, true);
+       desc_hint_in_state(hstate, &buf, "}, {error hints", HINT_STATE_ERROR, true);
+       appendStringInfoChar(&buf, '}');
+
+       ereport(pg_hint_plan_debug_message_level,
+                       (errmsg("%s", buf.data),
+                        errhidestmt(true),
+                        errhidecontext(true)));
 
        pfree(buf.data);
 }
@@ -869,6 +1208,24 @@ SetHintCmp(const SetHint *a, const SetHint *b)
 }
 
 static int
+RowsHintCmp(const RowsHint *a, const RowsHint *b)
+{
+       int     i;
+
+       if (a->nrels != b->nrels)
+               return a->nrels - b->nrels;
+
+       for (i = 0; i < a->nrels; i++)
+       {
+               int     result;
+               if ((result = RelnameCmp(&a->relnames[i], &b->relnames[i])) != 0)
+                       return result;
+       }
+
+       return 0;
+}
+
+static int
 HintCmp(const void *a, const void *b)
 {
        const Hint *hinta = *((const Hint **) a);
@@ -943,7 +1300,7 @@ skip_parenthesis(const char *str, char parenthesis)
  * Parsed token is truncated within NAMEDATALEN-1 bytes, when truncate is true.
  */
 static const char *
-parse_quote_value(const char *str, char **word, bool truncate)
+parse_quoted_value(const char *str, char **word, bool truncate)
 {
        StringInfoData  buf;
        bool                    in_quote;
@@ -989,7 +1346,8 @@ parse_quote_value(const char *str, char **word, bool truncate)
                                        break;
                        }
                }
-               else if (isspace(*str) || *str == ')' || *str == '"' || *str == '\0')
+               else if (isspace(*str) || *str == '(' || *str == ')' || *str == '"' ||
+                                *str == '\0')
                        break;
 
                appendStringInfoCharMacro(&buf, *str++);
@@ -1013,8 +1371,104 @@ parse_quote_value(const char *str, char **word, bool truncate)
        return str;
 }
 
+static OuterInnerRels *
+OuterInnerRelsCreate(char *name, List *outer_inner_list)
+{
+       OuterInnerRels *outer_inner;
+
+       outer_inner = palloc(sizeof(OuterInnerRels));
+       outer_inner->relation = name;
+       outer_inner->outer_inner_pair = outer_inner_list;
+
+       return outer_inner;
+}
+
+static const char *
+parse_parentheses_Leading_in(const char *str, OuterInnerRels **outer_inner)
+{
+       List   *outer_inner_pair = NIL;
+
+       if ((str = skip_parenthesis(str, '(')) == NULL)
+               return NULL;
+
+       skip_space(str);
+
+       /* Store words in parentheses into outer_inner_list. */
+       while(*str != ')' && *str != '\0')
+       {
+               OuterInnerRels *outer_inner_rels;
+
+               if (*str == '(')
+               {
+                       str = parse_parentheses_Leading_in(str, &outer_inner_rels);
+                       if (str == NULL)
+                               break;
+               }
+               else
+               {
+                       char   *name;
+
+                       if ((str = parse_quoted_value(str, &name, true)) == NULL)
+                               break;
+                       else
+                               outer_inner_rels = OuterInnerRelsCreate(name, NIL);
+               }
+
+               outer_inner_pair = lappend(outer_inner_pair, outer_inner_rels);
+               skip_space(str);
+       }
+
+       if (str == NULL ||
+               (str = skip_parenthesis(str, ')')) == NULL)
+       {
+               list_free(outer_inner_pair);
+               return NULL;
+       }
+
+       *outer_inner = OuterInnerRelsCreate(NULL, outer_inner_pair);
+
+       return str;
+}
+
+static const char *
+parse_parentheses_Leading(const char *str, List **name_list,
+       OuterInnerRels **outer_inner)
+{
+       char   *name;
+       bool    truncate = true;
+
+       if ((str = skip_parenthesis(str, '(')) == NULL)
+               return NULL;
+
+       skip_space(str);
+       if (*str =='(')
+       {
+               if ((str = parse_parentheses_Leading_in(str, outer_inner)) == NULL)
+                       return NULL;
+       }
+       else
+       {
+               /* Store words in parentheses into name_list. */
+               while(*str != ')' && *str != '\0')
+               {
+                       if ((str = parse_quoted_value(str, &name, truncate)) == NULL)
+                       {
+                               list_free(*name_list);
+                               return NULL;
+                       }
+
+                       *name_list = lappend(*name_list, name);
+                       skip_space(str);
+               }
+       }
+
+       if ((str = skip_parenthesis(str, ')')) == NULL)
+               return NULL;
+       return str;
+}
+
 static const char *
-parse_parentheses(const char *str, List **name_list, HintType type)
+parse_parentheses(const char *str, List **name_list, HintKeyword keyword)
 {
        char   *name;
        bool    truncate = true;
@@ -1027,7 +1481,7 @@ parse_parentheses(const char *str, List **name_list, HintType type)
        /* Store words in parentheses into name_list. */
        while(*str != ')' && *str != '\0')
        {
-               if ((str = parse_quote_value(str, &name, truncate)) == NULL)
+               if ((str = parse_quoted_value(str, &name, truncate)) == NULL)
                {
                        list_free(*name_list);
                        return NULL;
@@ -1036,7 +1490,10 @@ parse_parentheses(const char *str, List **name_list, HintType type)
                *name_list = lappend(*name_list, name);
                skip_space(str);
 
-               if (type == HINT_TYPE_SET)
+               if (keyword == HINT_KEYWORD_INDEXSCANREGEXP ||
+                       keyword == HINT_KEYWORD_INDEXONLYSCANREGEXP ||
+                       keyword == HINT_KEYWORD_BITMAPSCANREGEXP ||
+                       keyword == HINT_KEYWORD_SET)
                {
                        truncate = false;
                }
@@ -1070,7 +1527,7 @@ parse_hints(HintState *hstate, Query *parse, const char *str)
                        char   *keyword = parser->keyword;
                        Hint   *hint;
 
-                       if (strcasecmp(buf.data, keyword) != 0)
+                       if (pg_strcasecmp(buf.data, keyword) != 0)
                                continue;
 
                        hint = parser->create_func(head, keyword, parser->hint_keyword);
@@ -1121,39 +1578,263 @@ parse_hints(HintState *hstate, Query *parse, const char *str)
        pfree(buf.data);
 }
 
-/*
- * Do basic parsing of the query head comment.
+
+/* 
+ * Get hints from table by client-supplied query string and application name.
  */
-static HintState *
-parse_head_comment(Query *parse)
+static const char *
+get_hints_from_table(const char *client_query, const char *client_application)
 {
-       const char *p;
-       char       *head;
-       char       *tail;
-       int                     len;
-       int                     i;
-       HintState   *hstate;
+       const char *search_query =
+               "SELECT hints "
+               "  FROM hint_plan.hints "
+               " WHERE norm_query_string = $1 "
+               "   AND ( application_name = $2 "
+               "    OR application_name = '' ) "
+               " ORDER BY application_name DESC";
+       static SPIPlanPtr plan = NULL;
+       char   *hints = NULL;
+       Oid             argtypes[2] = { TEXTOID, TEXTOID };
+       Datum   values[2];
+       bool    nulls[2] = { false, false };
+       text   *qry;
+       text   *app;
 
-       /* get client-supplied query string. */
-       if (stmt_name)
+       PG_TRY();
        {
-               PreparedStatement  *entry;
+               bool snapshot_set = false;
+
+               hint_inhibit_level++;
+
+               if (!ActiveSnapshotSet())
+               {
+                       PushActiveSnapshot(GetTransactionSnapshot());
+                       snapshot_set = true;
+               }
+       
+               SPI_connect();
+       
+               if (plan == NULL)
+               {
+                       SPIPlanPtr      p;
+                       p = SPI_prepare(search_query, 2, argtypes);
+                       plan = SPI_saveplan(p);
+                       SPI_freeplan(p);
+               }
+       
+               qry = cstring_to_text(client_query);
+               app = cstring_to_text(client_application);
+               values[0] = PointerGetDatum(qry);
+               values[1] = PointerGetDatum(app);
+       
+               SPI_execute_plan(plan, values, nulls, true, 1);
+       
+               if (SPI_processed > 0)
+               {
+                       char    *buf;
+       
+                       hints = SPI_getvalue(SPI_tuptable->vals[0],
+                                                                SPI_tuptable->tupdesc, 1);
+                       /*
+                        * Here we use SPI_palloc to ensure that hints string is valid even
+                        * after SPI_finish call.  We can't use simple palloc because it
+                        * allocates memory in SPI's context and that context is deleted in
+                        * SPI_finish.
+                        */
+                       buf = SPI_palloc(strlen(hints) + 1);
+                       strcpy(buf, hints);
+                       hints = buf;
+               }
+       
+               SPI_finish();
 
-               entry = FetchPreparedStatement(stmt_name, true);
-               p = entry->plansource->query_string;
+               if (snapshot_set)
+                       PopActiveSnapshot();
+
+               hint_inhibit_level--;
        }
-       else
-               p = debug_query_string;
+       PG_CATCH();
+       {
+               hint_inhibit_level--;
+               PG_RE_THROW();
+       }
+       PG_END_TRY();
+
+       return hints;
+}
+
+/*
+ * Get client-supplied query string. Addtion to that the jumbled query is
+ * supplied if the caller requested. From the restriction of JumbleQuery, some
+ * kind of query needs special amendments. Reutrns NULL if this query doesn't
+ * change the current hint. This function returns NULL also when something
+ * wrong has happend and let the caller continue using the current hints.
+ */
+static const char *
+get_query_string(ParseState *pstate, Query *query, Query **jumblequery)
+{
+       const char *p = debug_query_string;
+
+       /*
+        * If debug_query_string is set, it is the top level statement. But in some
+        * cases we reach here with debug_query_string set NULL for example in the
+        * case of DESCRIBE message handling or EXECUTE command. We may still see a
+        * candidate top-level query in pstate in the case.
+        */
+       if (pstate && pstate->p_sourcetext)
+               p = pstate->p_sourcetext;
+
+       /* We don't see a query string, return NULL */
+       if (!p)
+               return NULL;
+
+       if (jumblequery != NULL)
+               *jumblequery = query;
+
+       /* Query for DeclareCursorStmt is CMD_SELECT and has query->utilityStmt */
+       if (query->commandType == CMD_UTILITY || query->utilityStmt)
+       {
+               Query *target_query = query;
+
+               /*
+                * Some utility statements have a subquery that we can hint on.  Since
+                * EXPLAIN can be placed before other kind of utility statements and
+                * EXECUTE can be contained other kind of utility statements, these
+                * conditions are not mutually exclusive and should be considered in
+                * this order.
+                */
+               if (IsA(target_query->utilityStmt, ExplainStmt))
+               {
+                       ExplainStmt *stmt = (ExplainStmt *)target_query->utilityStmt;
+                       
+                       Assert(IsA(stmt->query, Query));
+                       target_query = (Query *)stmt->query;
+
+                       /* strip out the top-level query for further processing */
+                       if (target_query->commandType == CMD_UTILITY &&
+                               target_query->utilityStmt != NULL)
+                               target_query = (Query *)target_query->utilityStmt;
+               }
+
+               /*
+                * JumbleQuery does  not accept  a Query that  has utilityStmt.  On the
+                * other  hand DeclareCursorStmt  is in  a  bit strange  shape that  is
+                * flipped upside down.
+                */
+               if (IsA(target_query, Query) &&
+                       target_query->utilityStmt &&
+                       IsA(target_query->utilityStmt, DeclareCursorStmt))
+               {
+                       /*
+                        * The given Query cannot be modified so copy it and modify so that
+                        * JumbleQuery can accept it.
+                        */
+                       Assert(IsA(target_query, Query) &&
+                                  target_query->commandType == CMD_SELECT);
+                       target_query = copyObject(target_query);
+                       target_query->utilityStmt = NULL;
+               }
+
+               if (IsA(target_query, CreateTableAsStmt))
+               {
+                       CreateTableAsStmt  *stmt = (CreateTableAsStmt *) target_query;
+
+                       Assert(IsA(stmt->query, Query));
+                       target_query = (Query *) stmt->query;
+
+                       /* strip out the top-level query for further processing */
+                       if (target_query->commandType == CMD_UTILITY &&
+                               target_query->utilityStmt != NULL)
+                               target_query = (Query *)target_query->utilityStmt;
+               }
+
+               if (IsA(target_query, ExecuteStmt))
+               {
+                       /*
+                        * Use the prepared query for EXECUTE. The Query for jumble
+                        * also replaced with the corresponding one.
+                        */
+                       ExecuteStmt *stmt = (ExecuteStmt *)target_query;
+                       PreparedStatement  *entry;
+
+                       entry = FetchPreparedStatement(stmt->name, true);
+
+                       if (entry->plansource->is_valid)
+                       {
+                               p = entry->plansource->query_string;
+                               target_query = (Query *) linitial (entry->plansource->query_list);
+                       }
+                       else
+                       {
+                               /* igonre the hint for EXECUTE if invalidated */
+                               p = NULL;
+                               target_query = NULL;
+                       }
+               }
+                       
+               /* JumbleQuery accespts only a non-utility Query */
+               if (target_query &&
+                       (!IsA(target_query, Query) ||
+                        target_query->utilityStmt != NULL))
+                       target_query = NULL;
+
+               if (jumblequery)
+                       *jumblequery = target_query;
+       }
+       /*
+        * Return NULL if pstate is not of top-level query.  We don't need this
+        * when jumble info is not requested or cannot do this when pstate is NULL.
+        */
+       else if (!jumblequery && pstate && pstate->p_sourcetext != p &&
+                        strcmp(pstate->p_sourcetext, p) != 0)
+               p = NULL;
+
+       return p;
+}
+
+/*
+ * Get hints from the head block comment in client-supplied query string.
+ */
+static const char *
+get_hints_from_comment(const char *p)
+{
+       const char *hint_head;
+       char       *head;
+       char       *tail;
+       int                     len;
 
        if (p == NULL)
                return NULL;
 
        /* extract query head comment. */
-       len = strlen(HINT_START);
-       skip_space(p);
-       if (strncmp(p, HINT_START, len))
+       hint_head = strstr(p, HINT_START);
+       if (hint_head == NULL)
                return NULL;
+       for (;p < hint_head; p++)
+       {
+               /*
+                * Allow these characters precedes hint comment:
+                *   - digits
+                *   - alphabets which are in ASCII range
+                *   - space, tabs and new-lines
+                *   - underscores, for identifier
+                *   - commas, for SELECT clause, EXPLAIN and PREPARE
+                *   - parentheses, for EXPLAIN and PREPARE
+                *
+                * Note that we don't use isalpha() nor isalnum() in ctype.h here to
+                * avoid behavior which depends on locale setting.
+                */
+               if (!(*p >= '0' && *p <= '9') &&
+                       !(*p >= 'A' && *p <= 'Z') &&
+                       !(*p >= 'a' && *p <= 'z') &&
+                       !isspace(*p) &&
+                       *p != '_' &&
+                       *p != ',' &&
+                       *p != '(' && *p != ')')
+                       return NULL;
+       }
 
+       len = strlen(HINT_START);
        head = (char *) p;
        p += len;
        skip_space(p);
@@ -1179,8 +1860,25 @@ parse_head_comment(Query *parse)
        head[len] = '\0';
        p = head;
 
+       return p;
+}
+
+/*
+ * Parse hints that got, create hint struct from parse tree and parse hints.
+ */
+static HintState *
+create_hintstate(Query *parse, const char *hints)
+{
+       const char *p;
+       int                     i;
+       HintState   *hstate;
+
+       if (hints == NULL)
+               return NULL;
+
+       p = hints;
        hstate = HintStateCreate();
-       hstate->hint_str = head;
+       hstate->hint_str = (char *) hints;
 
        /* parse each hint. */
        parse_hints(hstate, parse, p);
@@ -1205,7 +1903,7 @@ parse_head_comment(Query *parse)
 
        /*
         * If an object (or a set of objects) has multiple hints of same hint-type,
-        * only the last hint is valid and others are igonred in planning.
+        * only the last hint is valid and others are ignored in planning.
         * Hints except the last are marked as 'duplicated' to remember the order.
         */
        for (i = 0; i < hstate->nall_hints - 1; i++)
@@ -1214,6 +1912,13 @@ parse_head_comment(Query *parse)
                Hint   *next_hint = hstate->all_hints[i + 1];
 
                /*
+                * Leading hint is marked as 'duplicated' in transform_join_hints.
+                */
+               if (cur_hint->type == HINT_TYPE_LEADING &&
+                       next_hint->type == HINT_TYPE_LEADING)
+                       continue;
+
+               /*
                 * Note that we need to pass addresses of hint pointers, because
                 * HintCmp is designed to sort array of Hint* by qsort.
                 */
@@ -1230,16 +1935,14 @@ parse_head_comment(Query *parse)
         * array which consists of all hints.
         */
        hstate->scan_hints = (ScanMethodHint **) hstate->all_hints;
-       hstate->join_hints = (JoinMethodHint **) hstate->all_hints +
-               hstate->num_hints[HINT_TYPE_SCAN_METHOD];
-       hstate->leading_hint = (LeadingHint *) hstate->all_hints[
-               hstate->num_hints[HINT_TYPE_SCAN_METHOD] +
-               hstate->num_hints[HINT_TYPE_JOIN_METHOD] +
-               hstate->num_hints[HINT_TYPE_LEADING] - 1];
-       hstate->set_hints = (SetHint **) hstate->all_hints +
-               hstate->num_hints[HINT_TYPE_SCAN_METHOD] +
-               hstate->num_hints[HINT_TYPE_JOIN_METHOD] +
-               hstate->num_hints[HINT_TYPE_LEADING];
+       hstate->join_hints = (JoinMethodHint **) (hstate->scan_hints +
+               hstate->num_hints[HINT_TYPE_SCAN_METHOD]);
+       hstate->leading_hint = (LeadingHint **) (hstate->join_hints +
+               hstate->num_hints[HINT_TYPE_JOIN_METHOD]);
+       hstate->set_hints = (SetHint **) (hstate->leading_hint +
+               hstate->num_hints[HINT_TYPE_LEADING]);
+       hstate->rows_hints = (RowsHint **) (hstate->set_hints +
+               hstate->num_hints[HINT_TYPE_SET]);
 
        return hstate;
 }
@@ -1256,7 +1959,7 @@ ScanMethodHintParse(ScanMethodHint *hint, HintState *hstate, Query *parse,
        List               *name_list = NIL;
        int                             length;
 
-       if ((str = parse_parentheses(str, &name_list, hint->base.type)) == NULL)
+       if ((str = parse_parentheses(str, &name_list, hint_keyword)) == NULL)
                return NULL;
 
        /* Parse relation name and index name(s) if given hint accepts. */
@@ -1267,12 +1970,13 @@ ScanMethodHintParse(ScanMethodHint *hint, HintState *hstate, Query *parse,
                hint->indexnames = list_delete_first(name_list);
 
                /* check whether the hint accepts index name(s). */
-               if (hint_keyword != HINT_KEYWORD_INDEXSCAN &&
-#if PG_VERSION_NUM >= 90200
+               if (length != 1 &&
+                       hint_keyword != HINT_KEYWORD_INDEXSCAN &&
+                       hint_keyword != HINT_KEYWORD_INDEXSCANREGEXP &&
                        hint_keyword != HINT_KEYWORD_INDEXONLYSCAN &&
-#endif
+                       hint_keyword != HINT_KEYWORD_INDEXONLYSCANREGEXP &&
                        hint_keyword != HINT_KEYWORD_BITMAPSCAN &&
-                       length != 1)
+                       hint_keyword != HINT_KEYWORD_BITMAPSCANREGEXP)
                {
                        hint_ereport(str,
                                                 ("%s hint accepts only one relation.",
@@ -1299,9 +2003,17 @@ ScanMethodHintParse(ScanMethodHint *hint, HintState *hstate, Query *parse,
                case HINT_KEYWORD_INDEXSCAN:
                        hint->enforce_mask = ENABLE_INDEXSCAN;
                        break;
+               case HINT_KEYWORD_INDEXSCANREGEXP:
+                       hint->enforce_mask = ENABLE_INDEXSCAN;
+                       hint->regexp = true;
+                       break;
                case HINT_KEYWORD_BITMAPSCAN:
                        hint->enforce_mask = ENABLE_BITMAPSCAN;
                        break;
+               case HINT_KEYWORD_BITMAPSCANREGEXP:
+                       hint->enforce_mask = ENABLE_BITMAPSCAN;
+                       hint->regexp = true;
+                       break;
                case HINT_KEYWORD_TIDSCAN:
                        hint->enforce_mask = ENABLE_TIDSCAN;
                        break;
@@ -1317,14 +2029,16 @@ ScanMethodHintParse(ScanMethodHint *hint, HintState *hstate, Query *parse,
                case HINT_KEYWORD_NOTIDSCAN:
                        hint->enforce_mask = ENABLE_ALL_SCAN ^ ENABLE_TIDSCAN;
                        break;
-#if PG_VERSION_NUM >= 90200
                case HINT_KEYWORD_INDEXONLYSCAN:
                        hint->enforce_mask = ENABLE_INDEXSCAN | ENABLE_INDEXONLYSCAN;
                        break;
+               case HINT_KEYWORD_INDEXONLYSCANREGEXP:
+                       hint->enforce_mask = ENABLE_INDEXSCAN | ENABLE_INDEXONLYSCAN;
+                       hint->regexp = true;
+                       break;
                case HINT_KEYWORD_NOINDEXONLYSCAN:
                        hint->enforce_mask = ENABLE_ALL_SCAN ^ ENABLE_INDEXONLYSCAN;
                        break;
-#endif
                default:
                        hint_ereport(str, ("Unrecognized hint keyword \"%s\".", keyword));
                        return NULL;
@@ -1342,7 +2056,7 @@ JoinMethodHintParse(JoinMethodHint *hint, HintState *hstate, Query *parse,
        HintKeyword             hint_keyword = hint->base.hint_keyword;
        List               *name_list = NIL;
 
-       if ((str = parse_parentheses(str, &name_list, hint->base.type)) == NULL)
+       if ((str = parse_parentheses(str, &name_list, hint_keyword)) == NULL)
                return NULL;
 
        hint->nrels = list_length(name_list);
@@ -1408,25 +2122,86 @@ JoinMethodHintParse(JoinMethodHint *hint, HintState *hstate, Query *parse,
        return str;
 }
 
+static bool
+OuterInnerPairCheck(OuterInnerRels *outer_inner)
+{
+       ListCell *l;
+       if (outer_inner->outer_inner_pair == NIL)
+       {
+               if (outer_inner->relation)
+                       return true;
+               else
+                       return false;
+       }
+
+       if (list_length(outer_inner->outer_inner_pair) == 2)
+       {
+               foreach(l, outer_inner->outer_inner_pair)
+               {
+                       if (!OuterInnerPairCheck(lfirst(l)))
+                               return false;
+               }
+       }
+       else
+               return false;
+
+       return true;
+}
+
+static List *
+OuterInnerList(OuterInnerRels *outer_inner)
+{
+       List               *outer_inner_list = NIL;
+       ListCell           *l;
+       OuterInnerRels *outer_inner_rels;
+
+       foreach(l, outer_inner->outer_inner_pair)
+       {
+               outer_inner_rels = (OuterInnerRels *)(lfirst(l));
+
+               if (outer_inner_rels->relation != NULL)
+                       outer_inner_list = lappend(outer_inner_list,
+                                                                          outer_inner_rels->relation);
+               else
+                       outer_inner_list = list_concat(outer_inner_list,
+                                                                                  OuterInnerList(outer_inner_rels));
+       }
+       return outer_inner_list;
+}
+
 static const char *
 LeadingHintParse(LeadingHint *hint, HintState *hstate, Query *parse,
                                 const char *str)
 {
-       List   *name_list = NIL;
+       List               *name_list = NIL;
+       OuterInnerRels *outer_inner = NULL;
 
-       if ((str = parse_parentheses(str, &name_list, hint->base.type)) == NULL)
+       if ((str = parse_parentheses_Leading(str, &name_list, &outer_inner)) ==
+               NULL)
                return NULL;
 
+       if (outer_inner != NULL)
+               name_list = OuterInnerList(outer_inner);
+
        hint->relations = name_list;
+       hint->outer_inner = outer_inner;
 
        /* A Leading hint requires at least two relations */
-       if (list_length(hint->relations) < 2)
+       if ( hint->outer_inner == NULL && list_length(hint->relations) < 2)
        {
                hint_ereport(hint->base.hint_str,
                                         ("%s hint requires at least two relations.",
                                          HINT_LEADING));
                hint->base.state = HINT_STATE_ERROR;
        }
+       else if (hint->outer_inner != NULL &&
+                        !OuterInnerPairCheck(hint->outer_inner))
+       {
+               hint_ereport(hint->base.hint_str,
+                                        ("%s hint requires two sets of relations when parentheses nests.",
+                                         HINT_LEADING));
+               hint->base.state = HINT_STATE_ERROR;
+       }
 
        return str;
 }
@@ -1436,7 +2211,8 @@ SetHintParse(SetHint *hint, HintState *hstate, Query *parse, const char *str)
 {
        List   *name_list = NIL;
 
-       if ((str = parse_parentheses(str, &name_list, hint->base.type)) == NULL)
+       if ((str = parse_parentheses(str, &name_list, hint->base.hint_keyword))
+               == NULL)
                return NULL;
 
        hint->words = name_list;
@@ -1458,6 +2234,104 @@ SetHintParse(SetHint *hint, HintState *hstate, Query *parse, const char *str)
        return str;
 }
 
+static const char *
+RowsHintParse(RowsHint *hint, HintState *hstate, Query *parse,
+                         const char *str)
+{
+       HintKeyword             hint_keyword = hint->base.hint_keyword;
+       List               *name_list = NIL;
+       char               *rows_str;
+       char               *end_ptr;
+       ListCell   *l;
+       int                     i = 0;
+
+       if ((str = parse_parentheses(str, &name_list, hint_keyword)) == NULL)
+               return NULL;
+
+       /* Last element must be rows specification */
+       hint->nrels = list_length(name_list) - 1;
+
+       if (hint->nrels < 1)
+       {
+               hint_ereport(str,
+                                        ("%s hint needs at least one relation followed by one correction term.",
+                                         hint->base.keyword));
+               hint->base.state = HINT_STATE_ERROR;
+
+               return str;
+       }
+       
+
+       /*
+        * Transform relation names from list to array to sort them with qsort
+        * after.
+        */
+       hint->relnames = palloc(sizeof(char *) * hint->nrels);
+       foreach (l, name_list)
+       {
+               if (hint->nrels <= i)
+                       break;
+               hint->relnames[i] = lfirst(l);
+               i++;
+       }
+
+       /* Retieve rows estimation */
+       rows_str = list_nth(name_list, hint->nrels);
+       hint->rows_str = rows_str;              /* store as-is for error logging */
+       if (rows_str[0] == '#')
+       {
+               hint->value_type = RVT_ABSOLUTE;
+               rows_str++;
+       }
+       else if (rows_str[0] == '+')
+       {
+               hint->value_type = RVT_ADD;
+               rows_str++;
+       }
+       else if (rows_str[0] == '-')
+       {
+               hint->value_type = RVT_SUB;
+               rows_str++;
+       }
+       else if (rows_str[0] == '*')
+       {
+               hint->value_type = RVT_MULTI;
+               rows_str++;
+       }
+       else
+       {
+               hint_ereport(rows_str, ("Unrecognized rows value type notation."));
+               hint->base.state = HINT_STATE_ERROR;
+               return str;
+       }
+       hint->rows = strtod(rows_str, &end_ptr);
+       if (*end_ptr)
+       {
+               hint_ereport(rows_str,
+                                        ("%s hint requires valid number as rows estimation.",
+                                         hint->base.keyword));
+               hint->base.state = HINT_STATE_ERROR;
+               return str;
+       }
+
+       /* A join hint requires at least two relations */
+       if (hint->nrels < 2)
+       {
+               hint_ereport(str,
+                                        ("%s hint requires at least two relations.",
+                                         hint->base.keyword));
+               hint->base.state = HINT_STATE_ERROR;
+               return str;
+       }
+
+       list_free(name_list);
+
+       /* Sort relnames in alphabetical order. */
+       qsort(hint->relnames, hint->nrels, sizeof(char *), RelnameCmp);
+
+       return str;
+}
+
 /*
  * set GUC parameter functions
  */
@@ -1472,13 +2346,8 @@ set_config_option_wrapper(const char *name, const char *value,
 
        PG_TRY();
        {
-#if PG_VERSION_NUM >= 90200
-               result = set_config_option(name, value, context, source,
-                                                                  action, changeVal, 0);
-#else
                result = set_config_option(name, value, context, source,
-                                                                  action, changeVal);
-#endif
+                                                                  action, changeVal, 0, false);
        }
        PG_CATCH();
        {
@@ -1489,10 +2358,12 @@ set_config_option_wrapper(const char *name, const char *value,
                errdata = CopyErrorData();
                FlushErrorState();
 
-               ereport(elevel, (errcode(errdata->sqlerrcode),
-                               errmsg("%s", errdata->message),
-                               errdata->detail ? errdetail("%s", errdata->detail) : 0,
-                               errdata->hint ? errhint("%s", errdata->hint) : 0));
+               ereport(elevel,
+                               (errcode(errdata->sqlerrcode),
+                                errmsg("%s", errdata->message),
+                                errdata->detail ? errdetail("%s", errdata->detail) : 0,
+                                errdata->hint ? errhint("%s", errdata->hint) : 0));
+               msgqno = qno;
                FreeErrorData(errdata);
        }
        PG_END_TRY();
@@ -1518,7 +2389,7 @@ set_config_options(SetHint **options, int noptions, GucContext context)
 
                result = set_config_option_wrapper(hint->name, hint->value, context,
                                                                                   PGC_S_SESSION, GUC_ACTION_SAVE, true,
-                                                                                  pg_hint_plan_parse_messages);
+                                                                                  pg_hint_plan_parse_message_level);
                if (result != 0)
                        hint->base.state = HINT_STATE_USED;
                else
@@ -1540,9 +2411,7 @@ set_scan_config_options(unsigned char enforce_mask, GucContext context)
 
        if (enforce_mask == ENABLE_SEQSCAN || enforce_mask == ENABLE_INDEXSCAN ||
                enforce_mask == ENABLE_BITMAPSCAN || enforce_mask == ENABLE_TIDSCAN
-#if PG_VERSION_NUM >= 90200
                || enforce_mask == (ENABLE_INDEXSCAN | ENABLE_INDEXONLYSCAN)
-#endif
                )
                mask = enforce_mask;
        else
@@ -1552,9 +2421,7 @@ set_scan_config_options(unsigned char enforce_mask, GucContext context)
        SET_CONFIG_OPTION("enable_indexscan", ENABLE_INDEXSCAN);
        SET_CONFIG_OPTION("enable_bitmapscan", ENABLE_BITMAPSCAN);
        SET_CONFIG_OPTION("enable_tidscan", ENABLE_TIDSCAN);
-#if PG_VERSION_NUM >= 90200
        SET_CONFIG_OPTION("enable_indexonlyscan", ENABLE_INDEXONLYSCAN);
-#endif
 }
 
 static void
@@ -1574,112 +2441,6 @@ set_join_config_options(unsigned char enforce_mask, GucContext context)
 }
 
 /*
- * pg_hint_plan hook functions
- */
-
-static void
-pg_hint_plan_ProcessUtility(Node *parsetree, const char *queryString,
-                                                       ParamListInfo params, bool isTopLevel,
-                                                       DestReceiver *dest, char *completionTag)
-{
-       Node                               *node;
-
-       if (!pg_hint_plan_enable_hint)
-       {
-               if (prev_ProcessUtility)
-                       (*prev_ProcessUtility) (parsetree, queryString, params,
-                                                                       isTopLevel, dest, completionTag);
-               else
-                       standard_ProcessUtility(parsetree, queryString, params,
-                                                                       isTopLevel, dest, completionTag);
-
-               return;
-       }
-
-       node = parsetree;
-       if (IsA(node, ExplainStmt))
-       {
-               /*
-                * Draw out parse tree of actual query from Query struct of EXPLAIN
-                * statement.
-                */
-               ExplainStmt        *stmt;
-               Query              *query;
-
-               stmt = (ExplainStmt *) node;
-
-               Assert(IsA(stmt->query, Query));
-               query = (Query *) stmt->query;
-
-               if (query->commandType == CMD_UTILITY && query->utilityStmt != NULL)
-                       node = query->utilityStmt;
-       }
-
-       /*
-        * If the query was a EXECUTE or CREATE TABLE AS EXECUTE, get query string
-        * specified to preceding PREPARE command to use it as source of hints.
-        */
-       if (IsA(node, ExecuteStmt))
-       {
-               ExecuteStmt        *stmt;
-
-               stmt = (ExecuteStmt *) node;
-               stmt_name = stmt->name;
-       }
-#if PG_VERSION_NUM >= 90200
-       /*
-        * CREATE AS EXECUTE behavior has changed since 9.2, so we must handle it
-        * specially here.
-        */
-       if (IsA(node, CreateTableAsStmt))
-       {
-               CreateTableAsStmt          *stmt;
-               Query              *query;
-
-               stmt = (CreateTableAsStmt *) node;
-               Assert(IsA(stmt->query, Query));
-               query = (Query *) stmt->query;
-
-               if (query->commandType == CMD_UTILITY &&
-                       IsA(query->utilityStmt, ExecuteStmt))
-               {
-                       ExecuteStmt *estmt = (ExecuteStmt *) query->utilityStmt;
-                       stmt_name = estmt->name;
-               }
-       }
-#endif
-       if (stmt_name)
-       {
-               PG_TRY();
-               {
-                       if (prev_ProcessUtility)
-                               (*prev_ProcessUtility) (parsetree, queryString, params,
-                                                                               isTopLevel, dest, completionTag);
-                       else
-                               standard_ProcessUtility(parsetree, queryString, params,
-                                                                               isTopLevel, dest, completionTag);
-               }
-               PG_CATCH();
-               {
-                       stmt_name = NULL;
-                       PG_RE_THROW();
-               }
-               PG_END_TRY();
-
-               stmt_name = NULL;
-
-               return;
-       }
-
-       if (prev_ProcessUtility)
-               (*prev_ProcessUtility) (parsetree, queryString, params,
-                                                               isTopLevel, dest, completionTag);
-       else
-               standard_ProcessUtility(parsetree, queryString, params,
-                                                               isTopLevel, dest, completionTag);
-}
-
-/*
  * Push a hint into hint stack which is implemented with List struct.  Head of
  * list is top of stack.
  */
@@ -1713,46 +2474,287 @@ pop_hint(void)
                current_hint = (HintState *) lfirst(list_head(HintStateStack));
 }
 
-static PlannedStmt *
-pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
+/*
+ * Retrieve and store hint string from given query or from the hint table.
+ */
+static void
+get_current_hint_string(ParseState *pstate, Query *query)
+{
+       const char *query_str;
+       MemoryContext   oldcontext;
+
+       /* do nothing under hint table search */
+       if (hint_inhibit_level > 0)
+               return;
+
+       /* We alredy have one, don't parse it again. */
+       if (current_hint_retrieved)
+               return;
+
+       /* Don't parse the current query hereafter */
+       current_hint_retrieved = true;
+
+       if (!pg_hint_plan_enable_hint)
+       {
+               if (current_hint_str)
+               {
+                       pfree((void *)current_hint_str);
+                       current_hint_str = NULL;
+               }
+               return;
+       }
+
+       /* increment the query number */
+       qnostr[0] = 0;
+       if (debug_level > 1)
+               snprintf(qnostr, sizeof(qnostr), "[qno=0x%x]", qno++);
+       qno++;
+
+       /* search the hint table for a hint if requested */
+       if (pg_hint_plan_enable_hint_table)
+       {
+               int                             query_len;
+               pgssJumbleState jstate;
+               Query              *jumblequery;
+               char               *normalized_query = NULL;
+
+               query_str = get_query_string(pstate, query, &jumblequery);
+
+               /* If this query is not for hint, just return */
+               if (!query_str)
+                       return;
+
+               /* clear the previous hint string */
+               if (current_hint_str)
+               {
+                       pfree((void *)current_hint_str);
+                       current_hint_str = NULL;
+               }
+               
+               if (jumblequery)
+               {
+                       /*
+                        * XXX: normalization code is copied from pg_stat_statements.c.
+                        * Make sure to keep up-to-date with it.
+                        */
+                       jstate.jumble = (unsigned char *) palloc(JUMBLE_SIZE);
+                       jstate.jumble_len = 0;
+                       jstate.clocations_buf_size = 32;
+                       jstate.clocations = (pgssLocationLen *)
+                               palloc(jstate.clocations_buf_size * sizeof(pgssLocationLen));
+                       jstate.clocations_count = 0;
+
+                       JumbleQuery(&jstate, jumblequery);
+
+                       /*
+                        * Normalize the query string by replacing constants with '?'
+                        */
+                       /*
+                        * Search hint string which is stored keyed by query string
+                        * and application name.  The query string is normalized to allow
+                        * fuzzy matching.
+                        *
+                        * Adding 1 byte to query_len ensures that the returned string has
+                        * a terminating NULL.
+                        */
+                       query_len = strlen(query_str) + 1;
+                       normalized_query =
+                               generate_normalized_query(&jstate, query_str,
+                                                                                 &query_len,
+                                                                                 GetDatabaseEncoding());
+
+                       /*
+                        * find a hint for the normalized query. the result should be in
+                        * TopMemoryContext
+                        */
+                       oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+                       current_hint_str =
+                               get_hints_from_table(normalized_query, application_name);
+                       MemoryContextSwitchTo(oldcontext);
+
+                       if (debug_level > 1)
+                       {
+                               if (current_hint_str)
+                                       ereport(pg_hint_plan_debug_message_level,
+                                                       (errmsg("pg_hint_plan[qno=0x%x]: "
+                                                                       "post_parse_analyze_hook: "
+                                                                       "hints from table: \"%s\": "
+                                                                       "normalized_query=\"%s\", "
+                                                                       "application name =\"%s\"",
+                                                                       qno, current_hint_str,
+                                                                       normalized_query, application_name),
+                                                        errhidestmt(msgqno != qno),
+                                                        errhidecontext(msgqno != qno)));
+                               else
+                                       ereport(pg_hint_plan_debug_message_level,
+                                                       (errmsg("pg_hint_plan[qno=0x%x]: "
+                                                                       "no match found in table:  "
+                                                                       "application name = \"%s\", "
+                                                                       "normalized_query=\"%s\"",
+                                                                       qno, application_name,
+                                                                       normalized_query),
+                                                        errhidestmt(msgqno != qno),
+                                                        errhidecontext(msgqno != qno)));
+
+                               msgqno = qno;
+                       }
+               }
+
+               /* retrun if we have hint here */
+               if (current_hint_str)
+                       return;
+       }
+       else
+               query_str = get_query_string(pstate, query, NULL);
+
+       if (query_str)
+       {
+               /*
+                * get hints from the comment. However we may have the same query
+                * string with the previous call, but the extra comparison seems no
+                * use..
+                */
+               if (current_hint_str)
+                       pfree((void *)current_hint_str);
+
+               oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+               current_hint_str = get_hints_from_comment(query_str);
+               MemoryContextSwitchTo(oldcontext);
+       }
+       else
+       {
+               /*
+                * Failed to get query. We would be in fetching invalidated
+                * plancache. Try the next chance.
+                */
+               current_hint_retrieved = false;
+       }
+
+       if (debug_level > 1)
+       {
+               if (debug_level == 1 && query_str && debug_query_string &&
+                       strcmp(query_str, debug_query_string))
+                       ereport(pg_hint_plan_debug_message_level,
+                                       (errmsg("hints in comment=\"%s\"",
+                                                       current_hint_str ? current_hint_str : "(none)"),
+                                        errhidestmt(msgqno != qno),
+                                        errhidecontext(msgqno != qno)));
+               else
+                       ereport(pg_hint_plan_debug_message_level,
+                                       (errmsg("hints in comment=\"%s\", query=\"%s\", debug_query_string=\"%s\"",
+                                                       current_hint_str ? current_hint_str : "(none)",
+                                                       query_str ? query_str : "(none)",
+                                                       debug_query_string ? debug_query_string : "(none)"),
+                                        errhidestmt(msgqno != qno),
+                                        errhidecontext(msgqno != qno)));
+               msgqno = qno;
+       }
+}
+
+/*
+ * Retrieve hint string from the current query.
+ */
+static void
+pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query)
+{
+       if (prev_post_parse_analyze_hook)
+               prev_post_parse_analyze_hook(pstate, query);
+
+       /* always retrieve hint from the top-level query string */
+       if (plpgsql_recurse_level == 0)
+               current_hint_retrieved = false;
+
+       get_current_hint_string(pstate, query);
+}
+
+/*
+ * We need to reset current_hint_retrieved flag always when a command execution
+ * is finished. This is true even for a pure utility command that doesn't
+ * involve planning phase.
+ */
+static void
+pg_hint_plan_ProcessUtility(Node *parsetree, const char *queryString,
+                                       ProcessUtilityContext context, ParamListInfo params,
+                                       DestReceiver *dest, char *completionTag)
+{
+       if (prev_ProcessUtility_hook)
+               prev_ProcessUtility_hook(parsetree, queryString, context, params,
+                                                                dest, completionTag);
+       else
+               standard_ProcessUtility(parsetree, queryString, context, params,
+                                                                dest, completionTag);
+
+       if (plpgsql_recurse_level == 0)
+               current_hint_retrieved = false;
+}
+
+/*
+ * Read and set up hint information
+ */
+static PlannedStmt *
+pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 {
        int                             save_nestlevel;
        PlannedStmt        *result;
        HintState          *hstate;
+       const char         *prev_hint_str = NULL;
 
        /*
-        * Use standard planner if pg_hint_plan is disabled.  Other hook functions
-        * try to change plan with current_hint if any, so set it to NULL.
+        * Use standard planner if pg_hint_plan is disabled or current nesting 
+        * depth is nesting depth of SPI calls. Other hook functions try to change
+        * plan with current_hint if any, so set it to NULL.
         */
-       if (!pg_hint_plan_enable_hint)
+       if (!pg_hint_plan_enable_hint || hint_inhibit_level > 0)
        {
-               current_hint = NULL;
-
-               if (prev_planner)
-                       return (*prev_planner) (parse, cursorOptions, boundParams);
-               else
-                       return standard_planner(parse, cursorOptions, boundParams);
+               if (debug_level > 1)
+                       ereport(pg_hint_plan_debug_message_level,
+                                       (errmsg ("pg_hint_plan%s: planner: enable_hint=%d,"
+                                                        " hint_inhibit_level=%d",
+                                                        qnostr, pg_hint_plan_enable_hint,
+                                                        hint_inhibit_level),
+                                        errhidestmt(msgqno != qno)));
+               msgqno = qno;
+
+               goto standard_planner_proc;
        }
 
-       /* Create hint struct from parse tree. */
-       hstate = parse_head_comment(parse);
-
        /*
-        * Use standard planner if the statement has not valid hint.  Other hook
-        * functions try to change plan with current_hint if any, so set it to
-        * NULL.
+        * Support for nested plpgsql functions. This is quite ugly but this is the
+        * only point I could find where I can get the query string.
         */
-       if (!hstate)
+       if (plpgsql_recurse_level > 0 &&
+               error_context_stack && error_context_stack->arg)
        {
-               current_hint = NULL;
+               MemoryContext oldcontext;
 
-               if (prev_planner)
-                       return (*prev_planner) (parse, cursorOptions, boundParams);
-               else
-                       return standard_planner(parse, cursorOptions, boundParams);
+               if (current_hint_str)
+                       pfree((void *)current_hint_str);
+
+               oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+               current_hint_str =
+                       get_hints_from_comment((char *)error_context_stack->arg);
+               MemoryContextSwitchTo(oldcontext);
        }
 
        /*
+        * Query execution in extended protocol can be started without the analyze
+        * phase. In the case retrieve hint string here.
+        */
+       if (!current_hint_str)
+               get_current_hint_string(NULL, parse);
+
+       /* No hint, go the normal way */
+       if (!current_hint_str)
+               goto standard_planner_proc;
+
+       /* parse the hint into hint state struct */
+       hstate = create_hintstate(parse, pstrdup(current_hint_str));
+
+       /* run standard planner if the statement has not valid hint */
+       if (!hstate)
+               goto standard_planner_proc;
+       
+       /*
         * Push new hint struct to the hint stack to disable previous hint context.
         */
        push_hint(hstate);
@@ -1770,10 +2772,8 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
                current_hint->init_scan_mask |= ENABLE_BITMAPSCAN;
        if (enable_tidscan)
                current_hint->init_scan_mask |= ENABLE_TIDSCAN;
-#if PG_VERSION_NUM >= 90200
        if (enable_indexonlyscan)
                current_hint->init_scan_mask |= ENABLE_INDEXONLYSCAN;
-#endif
        if (enable_nestloop)
                current_hint->init_join_mask |= ENABLE_NESTLOOP;
        if (enable_mergejoin)
@@ -1781,9 +2781,26 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
        if (enable_hashjoin)
                current_hint->init_join_mask |= ENABLE_HASHJOIN;
 
+       if (debug_level > 1)
+       {
+               ereport(pg_hint_plan_debug_message_level,
+                               (errhidestmt(msgqno != qno),
+                                errmsg("pg_hint_plan%s: planner", qnostr))); 
+               msgqno = qno;
+       }
+
+       /*
+        * The planner call below may replace current_hint_str. Store and restore
+        * it so that the subsequent planning in the upper level doesn't get
+        * confused.
+        */
+       recurse_level++;
+       prev_hint_str = current_hint_str;
+       current_hint_str = NULL;
+       
        /*
-        * Use PG_TRY mechanism to recover GUC parameters and current_hint to the
-        * state when this planner started when error occurred in planner.
+        * Use PG_TRY mechanism to recover GUC parameters and current_hint_state to
+        * the state when this planner started when error occurred in planner.
         */
        PG_TRY();
        {
@@ -1791,6 +2808,9 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
                        result = (*prev_planner) (parse, cursorOptions, boundParams);
                else
                        result = standard_planner(parse, cursorOptions, boundParams);
+
+               current_hint_str = prev_hint_str;
+               recurse_level--;
        }
        PG_CATCH();
        {
@@ -1798,15 +2818,30 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
                 * Rollback changes of GUC parameters, and pop current hint context
                 * from hint stack to rewind the state.
                 */
+               current_hint_str = prev_hint_str;
+               recurse_level--;
                AtEOXact_GUC(true, save_nestlevel);
                pop_hint();
                PG_RE_THROW();
        }
        PG_END_TRY();
 
+
+       /*
+        * current_hint_str is useless after planning of the top-level query.
+        */
+       if (plpgsql_recurse_level < 1 && current_hint_str)
+       {
+               pfree((void *)current_hint_str);
+               current_hint_str = NULL;
+               current_hint_retrieved = false;
+       }
+
        /* Print hint in debug mode. */
-       if (pg_hint_plan_debug_print)
+       if (debug_level == 1)
                HintStateDump(current_hint);
+       else if (debug_level > 1)
+               HintStateDump2(current_hint);
 
        /*
         * Rollback changes of GUC parameters, and pop current hint context from
@@ -1816,13 +2851,34 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
        pop_hint();
 
        return result;
+
+standard_planner_proc:
+       if (debug_level > 1)
+       {
+               ereport(pg_hint_plan_debug_message_level,
+                               (errhidestmt(msgqno != qno),
+                                errmsg("pg_hint_plan%s: planner: no valid hint",
+                                               qnostr)));
+               msgqno = qno;
+       }
+       current_hint = NULL;
+       if (prev_planner)
+               result = (*prev_planner) (parse, cursorOptions, boundParams);
+       else
+               result = standard_planner(parse, cursorOptions, boundParams);
+
+       /* The upper-level planner still needs the current hint state */
+       if (HintStateStack != NIL)
+               current_hint = (HintState *) lfirst(list_head(HintStateStack));
+
+       return result;
 }
 
 /*
  * Return scan method hint which matches given aliasname.
  */
 static ScanMethodHint *
-find_scan_hint(PlannerInfo *root, RelOptInfo *rel)
+find_scan_hint(PlannerInfo *root, Index relid, RelOptInfo *rel)
 {
        RangeTblEntry  *rte;
        int                             i;
@@ -1832,10 +2888,10 @@ find_scan_hint(PlannerInfo *root, RelOptInfo *rel)
         *   - not a base relation
         *   - not an ordinary relation (such as join and subquery)
         */
-       if (rel->reloptkind != RELOPT_BASEREL || rel->rtekind != RTE_RELATION)
+       if (rel && (rel->reloptkind != RELOPT_BASEREL || rel->rtekind != RTE_RELATION))
                return NULL;
 
-       rte = root->simple_rte_array[rel->relid];
+       rte = root->simple_rte_array[relid];
 
        /* We can't force scan method of foreign tables */
        if (rte->relkind == RELKIND_FOREIGN_TABLE)
@@ -1857,6 +2913,33 @@ find_scan_hint(PlannerInfo *root, RelOptInfo *rel)
        return NULL;
 }
 
+/*
+ * regexeq
+ *
+ * Returns TRUE on match, FALSE on no match.
+ *
+ *   s1 --- the data to match against
+ *   s2 --- the pattern
+ *
+ * Because we copy s1 to NameData, make the size of s1 less than NAMEDATALEN.
+ */
+static bool
+regexpeq(const char *s1, const char *s2)
+{
+       NameData        name;
+       text       *regexp;
+       Datum           result;
+
+       strcpy(name.data, s1);
+       regexp = cstring_to_text(s2);
+
+       result = DirectFunctionCall2Coll(nameregexeq,
+                                                                        DEFAULT_COLLATION_OID,
+                                                                        NameGetDatum(&name),
+                                                                        PointerGetDatum(regexp));
+       return DatumGetBool(result);
+}
+
 static void
 delete_indexes(ScanMethodHint *hint, RelOptInfo *rel, Oid relationObjectId)
 {
@@ -1890,7 +2973,7 @@ delete_indexes(ScanMethodHint *hint, RelOptInfo *rel, Oid relationObjectId)
         * other than it.
         */
        prev = NULL;
-       if (pg_hint_plan_debug_print)
+       if (debug_level > 0)
                initStringInfo(&buf);
 
        for (cell = list_head(rel->indexlist); cell; cell = next)
@@ -1904,13 +2987,180 @@ delete_indexes(ScanMethodHint *hint, RelOptInfo *rel, Oid relationObjectId)
 
                foreach(l, hint->indexnames)
                {
-                       if (RelnameCmp(&indexname, &lfirst(l)) == 0)
+                       char   *hintname = (char *) lfirst(l);
+                       bool    result;
+
+                       if (hint->regexp)
+                               result = regexpeq(indexname, hintname);
+                       else
+                               result = RelnameCmp(&indexname, &hintname) == 0;
+
+                       if (result)
                        {
                                use_index = true;
-                               if (pg_hint_plan_debug_print)
+                               if (debug_level > 0)
+                               {
+                                       appendStringInfoCharMacro(&buf, ' ');
+                                       quote_value(&buf, indexname);
+                               }
+
+                               break;
+                       }
+               }
+
+               /*
+                * to make the index a candidate when definition of this index is
+                * matched with the index's definition of current_hint.
+                */
+               if (OidIsValid(relationObjectId) && !use_index)
+               {
+                       foreach(l, current_hint->parent_index_infos)
+                       {
+                               int                                     i;
+                               HeapTuple                       ht_idx;
+                               ParentIndexInfo    *p_info = (ParentIndexInfo *)lfirst(l);
+
+                               /* check to match the parameter of unique */
+                               if (p_info->indisunique != info->unique)
+                                       continue;
+
+                               /* check to match the parameter of index's method */
+                               if (p_info->method != info->relam)
+                                       continue;
+
+                               /* to check to match the indexkey's configuration */
+                               if ((list_length(p_info->column_names)) !=
+                                        info->ncolumns)
+                                       continue;
+
+                               /* check to match the indexkey's configuration */
+                               for (i = 0; i < info->ncolumns; i++)
+                               {
+                                       char       *c_attname = NULL;
+                                       char       *p_attname = NULL;
+
+                                       p_attname =
+                                               list_nth(p_info->column_names, i);
+
+                                       /* both are expressions */
+                                       if (info->indexkeys[i] == 0 && !p_attname)
+                                               continue;
+
+                                       /* one's column is expression, the other is not */
+                                       if (info->indexkeys[i] == 0 || !p_attname)
+                                               break;
+
+                                       c_attname = get_attname(relationObjectId,
+                                                                                               info->indexkeys[i]);
+
+                                       if (strcmp(p_attname, c_attname) != 0)
+                                               break;
+
+                                       if (p_info->indcollation[i] != info->indexcollations[i])
+                                               break;
+
+                                       if (p_info->opclass[i] != info->opcintype[i])
+                                               break;
+
+                                       if (((p_info->indoption[i] & INDOPTION_DESC) != 0) !=
+                                               info->reverse_sort[i])
+                                               break;
+
+                                       if (((p_info->indoption[i] & INDOPTION_NULLS_FIRST) != 0) !=
+                                               info->nulls_first[i])
+                                               break;
+
+                               }
+
+                               if (i != info->ncolumns)
+                                       continue;
+
+                               if ((p_info->expression_str && (info->indexprs != NIL)) ||
+                                       (p_info->indpred_str && (info->indpred != NIL)))
+                               {
+                                       /*
+                                        * Fetch the pg_index tuple by the Oid of the index
+                                        */
+                                       ht_idx = SearchSysCache1(INDEXRELID,
+                                                                                        ObjectIdGetDatum(info->indexoid));
+
+                                       /* check to match the expression's parameter of index */
+                                       if (p_info->expression_str &&
+                                               !heap_attisnull(ht_idx, Anum_pg_index_indexprs))
+                                       {
+                                               Datum       exprsDatum;
+                                               bool        isnull;
+                                               Datum       result;
+
+                                               /*
+                                                * to change the expression's parameter of child's
+                                                * index to strings
+                                                */
+                                               exprsDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
+                                                                                                        Anum_pg_index_indexprs,
+                                                                                                        &isnull);
+
+                                               result = DirectFunctionCall2(pg_get_expr,
+                                                                                                        exprsDatum,
+                                                                                                        ObjectIdGetDatum(
+                                                                                                                relationObjectId));
+
+                                               if (strcmp(p_info->expression_str,
+                                                                  text_to_cstring(DatumGetTextP(result))) != 0)
+                                               {
+                                                       /* Clean up */
+                                                       ReleaseSysCache(ht_idx);
+
+                                                       continue;
+                                               }
+                                       }
+
+                                       /* Check to match the predicate's parameter of index */
+                                       if (p_info->indpred_str &&
+                                               !heap_attisnull(ht_idx, Anum_pg_index_indpred))
+                                       {
+                                               Datum       predDatum;
+                                               bool        isnull;
+                                               Datum       result;
+
+                                               /*
+                                                * to change the predicate's parameter of child's
+                                                * index to strings
+                                                */
+                                               predDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
+                                                                                                        Anum_pg_index_indpred,
+                                                                                                        &isnull);
+
+                                               result = DirectFunctionCall2(pg_get_expr,
+                                                                                                        predDatum,
+                                                                                                        ObjectIdGetDatum(
+                                                                                                                relationObjectId));
+
+                                               if (strcmp(p_info->indpred_str,
+                                                                  text_to_cstring(DatumGetTextP(result))) != 0)
+                                               {
+                                                       /* Clean up */
+                                                       ReleaseSysCache(ht_idx);
+
+                                                       continue;
+                                               }
+                                       }
+
+                                       /* Clean up */
+                                       ReleaseSysCache(ht_idx);
+                               }
+                               else if (p_info->expression_str || (info->indexprs != NIL))
+                                       continue;
+                               else if (p_info->indpred_str || (info->indpred != NIL))
+                                       continue;
+
+                               use_index = true;
+
+                               /* to log the candidate of index */
+                               if (debug_level > 0)
                                {
                                        appendStringInfoCharMacro(&buf, ' ');
-                                       dump_quote_value(&buf, indexname);
+                                       quote_value(&buf, indexname);
                                }
 
                                break;
@@ -1925,86 +3175,304 @@ delete_indexes(ScanMethodHint *hint, RelOptInfo *rel, Oid relationObjectId)
                pfree(indexname);
        }
 
-       if (pg_hint_plan_debug_print)
+       if (debug_level == 1)
        {
                char   *relname;
+               StringInfoData  rel_buf;
 
                if (OidIsValid(relationObjectId))
                        relname = get_rel_name(relationObjectId);
                else
                        relname = hint->relname;
-               ereport(LOG,
-                               (errmsg("available indexes for %s(\"%s\"):%s",
-                                hint->base.keyword,
-                                relname, buf.data)));
+
+               initStringInfo(&rel_buf);
+               quote_value(&rel_buf, relname);
+
+               ereport(pg_hint_plan_debug_message_level,
+                               (errmsg("available indexes for %s(%s):%s",
+                                        hint->base.keyword,
+                                        rel_buf.data,
+                                        buf.data)));
                pfree(buf.data);
+               pfree(rel_buf.data);
+       }
+}
+
+/* 
+ * Return information of index definition.
+ */
+static ParentIndexInfo *
+get_parent_index_info(Oid indexoid, Oid relid)
+{
+       ParentIndexInfo *p_info = palloc(sizeof(ParentIndexInfo));
+       Relation            indexRelation;
+       Form_pg_index   index;
+       char               *attname;
+       int                             i;
+
+       indexRelation = index_open(indexoid, RowExclusiveLock);
+
+       index = indexRelation->rd_index;
+
+       p_info->indisunique = index->indisunique;
+       p_info->method = indexRelation->rd_rel->relam;
+
+       p_info->column_names = NIL;
+       p_info->indcollation = (Oid *) palloc(sizeof(Oid) * index->indnatts);
+       p_info->opclass = (Oid *) palloc(sizeof(Oid) * index->indnatts);
+       p_info->indoption = (int16 *) palloc(sizeof(Oid) * index->indnatts);
+
+       for (i = 0; i < index->indnatts; i++)
+       {
+               attname = get_attname(relid, index->indkey.values[i]);
+               p_info->column_names = lappend(p_info->column_names, attname);
+
+               p_info->indcollation[i] = indexRelation->rd_indcollation[i];
+               p_info->opclass[i] = indexRelation->rd_opcintype[i];
+               p_info->indoption[i] = indexRelation->rd_indoption[i];
+       }
+
+       /*
+        * to check to match the expression's parameter of index with child indexes
+        */
+       p_info->expression_str = NULL;
+       if(!heap_attisnull(indexRelation->rd_indextuple, Anum_pg_index_indexprs))
+       {
+               Datum       exprsDatum;
+               bool            isnull;
+               Datum           result;
+
+               exprsDatum = SysCacheGetAttr(INDEXRELID, indexRelation->rd_indextuple,
+                                                                        Anum_pg_index_indexprs, &isnull);
+
+               result = DirectFunctionCall2(pg_get_expr,
+                                                                        exprsDatum,
+                                                                        ObjectIdGetDatum(relid));
+
+               p_info->expression_str = text_to_cstring(DatumGetTextP(result));
+       }
+
+       /*
+        * to check to match the predicate's parameter of index with child indexes
+        */
+       p_info->indpred_str = NULL;
+       if(!heap_attisnull(indexRelation->rd_indextuple, Anum_pg_index_indpred))
+       {
+               Datum       predDatum;
+               bool            isnull;
+               Datum           result;
+
+               predDatum = SysCacheGetAttr(INDEXRELID, indexRelation->rd_indextuple,
+                                                                        Anum_pg_index_indpred, &isnull);
+
+               result = DirectFunctionCall2(pg_get_expr,
+                                                                        predDatum,
+                                                                        ObjectIdGetDatum(relid));
+
+               p_info->indpred_str = text_to_cstring(DatumGetTextP(result));
        }
+
+       index_close(indexRelation, NoLock);
+
+       return p_info;
 }
 
 static void
 pg_hint_plan_get_relation_info(PlannerInfo *root, Oid relationObjectId,
                                                           bool inhparent, RelOptInfo *rel)
 {
-       ScanMethodHint *hint;
+       ScanMethodHint *hint = NULL;
+       ListCell *l;
+       Index new_parent_relid = 0;
 
        if (prev_get_relation_info)
                (*prev_get_relation_info) (root, relationObjectId, inhparent, rel);
 
-       /* Do nothing if we don't have valid hint in this context. */
-       if (!current_hint)
+       /* 
+        * Do nothing if we don't have a valid hint in this context or current
+        * nesting depth is at SPI calls.
+        */
+       if (!current_hint || hint_inhibit_level > 0)
+       {
+               if (debug_level > 1)
+                       ereport(pg_hint_plan_debug_message_level,
+                                       (errhidestmt(true),
+                                        errmsg ("pg_hint_plan%s: get_relation_info"
+                                                        " no hint to apply: relation=%u(%s), inhparent=%d,"
+                                                        " current_hint=%p, hint_inhibit_level=%d",
+                                                        qnostr, relationObjectId,
+                                                        get_rel_name(relationObjectId),
+                                                        inhparent, current_hint, hint_inhibit_level)));
                return;
+       }
 
+       /*
+        * We could register the parent relation of the following children here
+        * when inhparent == true but inheritnce planner doesn't request
+        * information for inheritance parents. We also cannot distinguish the
+        * caller so we should always find the parents without this function being
+        * called for them.
+        */
        if (inhparent)
        {
-               /* store does relids of parent table. */
-               current_hint->parent_relid = rel->relid;
+               if (debug_level > 1)
+                       ereport(pg_hint_plan_debug_message_level,
+                                       (errhidestmt(true),
+                                        errmsg ("pg_hint_plan%s: get_relation_info"
+                                                        " skipping inh parent: relation=%u(%s), inhparent=%d,"
+                                                        " current_hint=%p, hint_inhibit_level=%d",
+                                                        qnostr, relationObjectId,
+                                                        get_rel_name(relationObjectId),
+                                                        inhparent, current_hint, hint_inhibit_level)));
+               return;
+       }
+
+       /* Forget about the parent of another subquery */
+       if (root != current_hint->current_root)
+               current_hint->parent_relid = 0;
+
+       /* Find the parent for this relation other than the registered parent */
+       foreach (l, root->append_rel_list)
+       {
+               AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
+
+               if (appinfo->child_relid == rel->relid)
+               {
+                       if (current_hint->parent_relid != appinfo->parent_relid)
+                       {
+                               new_parent_relid = appinfo->parent_relid;
+                               current_hint->current_root = root;
+                       }
+                       break;
+               }
+       }
+
+       if (!l)
+       {
+               /* This relation doesn't have a parent. Cancel current_hint. */
+               current_hint->parent_relid = 0;
+               current_hint->parent_hint = NULL;
        }
-       else if (current_hint->parent_relid != 0)
+
+       if (new_parent_relid > 0)
        {
                /*
-                * We use the same GUC parameter if this table is the child table of a
-                * table called pg_hint_plan_get_relation_info just before that.
+                * Here we found a parent relation different from the remembered one.
+                * Remember it, apply the scan mask of it and then resolve the index
+                * restriction in order to be used by its children.
                 */
-               ListCell   *l;
+               int scanmask = current_hint->init_scan_mask;
+               ScanMethodHint *parent_hint;
 
-               /* append_rel_list contains all append rels; ignore others */
-               foreach(l, root->append_rel_list)
+               current_hint->parent_relid = new_parent_relid;
+                               
+               /*
+                * Get and apply the hint for the new parent relation. It should be an
+                * ordinary relation so calling find_scan_hint with rel == NULL is
+                * safe.
+                */
+               current_hint->parent_hint = parent_hint = 
+                       find_scan_hint(root, current_hint->parent_relid, NULL);
+
+               if (parent_hint)
                {
-                       AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
+                       scanmask = current_hint->parent_hint->enforce_mask;
+                       parent_hint->base.state = HINT_STATE_USED;
 
-                       /* This rel is child table. */
-                       if (appinfo->parent_relid == current_hint->parent_relid &&
-                               appinfo->child_relid == rel->relid)
+                       /* Resolve index name mask (if any) using the parent. */
+                       if (parent_hint->indexnames)
                        {
-                               if (current_hint->parent_hint)
-                                       delete_indexes(current_hint->parent_hint, rel,
-                                                                  relationObjectId);
+                               Oid                     parentrel_oid;
+                               Relation        parent_rel;
 
-                               return;
+                               parentrel_oid =
+                                       root->simple_rte_array[current_hint->parent_relid]->relid;
+                               parent_rel = heap_open(parentrel_oid, NoLock);
+
+                               /* Search the parent relation for indexes match the hint spec */
+                               foreach(l, RelationGetIndexList(parent_rel))
+                               {
+                                       Oid         indexoid = lfirst_oid(l);
+                                       char       *indexname = get_rel_name(indexoid);
+                                       ListCell   *lc;
+                                       ParentIndexInfo *parent_index_info;
+
+                                       foreach(lc, parent_hint->indexnames)
+                                       {
+                                               if (RelnameCmp(&indexname, &lfirst(lc)) == 0)
+                                                       break;
+                                       }
+                                       if (!lc)
+                                               continue;
+
+                                       parent_index_info =
+                                               get_parent_index_info(indexoid, parentrel_oid);
+                                       current_hint->parent_index_infos =
+                                               lappend(current_hint->parent_index_infos, parent_index_info);
+                               }
+                               heap_close(parent_rel, NoLock);
                        }
                }
+                       
+               set_scan_config_options(scanmask, current_hint->context);
+       }
 
-               /* This rel is not inherit table. */
-               current_hint->parent_relid = 0;
-               current_hint->parent_hint = NULL;
+       if (current_hint->parent_hint != 0)
+       {
+               delete_indexes(current_hint->parent_hint, rel,
+                                          relationObjectId);
+
+               /* Scan fixation status is the same to the parent. */
+               if (debug_level > 1)
+                       ereport(pg_hint_plan_debug_message_level,
+                                       (errhidestmt(true),
+                                        errmsg("pg_hint_plan%s: get_relation_info:"
+                                                       " index deletion by parent hint: "
+                                                       "relation=%u(%s), inhparent=%d, current_hint=%p,"
+                                                       " hint_inhibit_level=%d",
+                                                       qnostr, relationObjectId,
+                                                       get_rel_name(relationObjectId),
+                                                       inhparent, current_hint, hint_inhibit_level)));
+               return;
        }
 
-       /*
-        * If scan method hint was given, reset GUC parameters which control
-        * planner behavior about choosing scan methods.
-        */
-       if ((hint = find_scan_hint(root, rel)) == NULL)
+       /* This table doesn't have a parent hint. Apply its own hint if any. */
+       if ((hint = find_scan_hint(root, rel->relid, rel)) != NULL)
        {
+               set_scan_config_options(hint->enforce_mask, current_hint->context);
+               hint->base.state = HINT_STATE_USED;
+
+               delete_indexes(hint, rel, InvalidOid);
+
+               if (debug_level > 1)
+                       ereport(pg_hint_plan_debug_message_level,
+                                       (errhidestmt(true),
+                                        errmsg ("pg_hint_plan%s: get_relation_info"
+                                                        " index deletion:"
+                                                        " relation=%u(%s), inhparent=%d, current_hint=%p,"
+                                                        " hint_inhibit_level=%d, scanmask=0x%x",
+                                                        qnostr, relationObjectId,
+                                                        get_rel_name(relationObjectId),
+                                                        inhparent, current_hint, hint_inhibit_level,
+                                                        hint->enforce_mask)));
+       }
+       else
+       {
+               if (debug_level > 1)
+                       ereport(pg_hint_plan_debug_message_level,
+                                       (errhidestmt (true),
+                                        errmsg ("pg_hint_plan%s: get_relation_info"
+                                                        " no hint applied:"
+                                                        " relation=%u(%s), inhparent=%d, current_hint=%p,"
+                                                        " hint_inhibit_level=%d, scanmask=0x%x",
+                                                        qnostr, relationObjectId,
+                                                        get_rel_name(relationObjectId),
+                                                        inhparent, current_hint, hint_inhibit_level,
+                                                        current_hint->init_scan_mask)));
                set_scan_config_options(current_hint->init_scan_mask,
                                                                current_hint->context);
-               return;
        }
-       set_scan_config_options(hint->enforce_mask, current_hint->context);
-       hint->base.state = HINT_STATE_USED;
-       if (inhparent)
-               current_hint->parent_hint = hint;
-
-       delete_indexes(hint, rel, InvalidOid);
+       return;
 }
 
 /*
@@ -2087,6 +3555,120 @@ find_join_hint(Relids joinrelids)
        return NULL;
 }
 
+static Relids
+OuterInnerJoinCreate(OuterInnerRels *outer_inner, LeadingHint *leading_hint,
+       PlannerInfo *root, List *initial_rels, HintState *hstate, int nbaserel)
+{
+       OuterInnerRels *outer_rels;
+       OuterInnerRels *inner_rels;
+       Relids                  outer_relids;
+       Relids                  inner_relids;
+       Relids                  join_relids;
+       JoinMethodHint *hint;
+
+       if (outer_inner->relation != NULL)
+       {
+               return bms_make_singleton(
+                                       find_relid_aliasname(root, outer_inner->relation,
+                                                                                initial_rels,
+                                                                                leading_hint->base.hint_str));
+       }
+
+       outer_rels = lfirst(outer_inner->outer_inner_pair->head);
+       inner_rels = lfirst(outer_inner->outer_inner_pair->tail);
+
+       outer_relids = OuterInnerJoinCreate(outer_rels,
+                                                                               leading_hint,
+                                                                               root,
+                                                                               initial_rels,
+                                                                               hstate,
+                                                                               nbaserel);
+       inner_relids = OuterInnerJoinCreate(inner_rels,
+                                                                               leading_hint,
+                                                                               root,
+                                                                               initial_rels,
+                                                                               hstate,
+                                                                               nbaserel);
+
+       join_relids = bms_add_members(outer_relids, inner_relids);
+
+       if (bms_num_members(join_relids) > nbaserel)
+               return join_relids;
+
+       /*
+        * If we don't have join method hint, create new one for the
+        * join combination with all join methods are enabled.
+        */
+       hint = find_join_hint(join_relids);
+       if (hint == NULL)
+       {
+               /*
+                * Here relnames is not set, since Relids bitmap is sufficient to
+                * control paths of this query afterward.
+                */
+               hint = (JoinMethodHint *) JoinMethodHintCreate(
+                                       leading_hint->base.hint_str,
+                                       HINT_LEADING,
+                                       HINT_KEYWORD_LEADING);
+               hint->base.state = HINT_STATE_USED;
+               hint->nrels = bms_num_members(join_relids);
+               hint->enforce_mask = ENABLE_ALL_JOIN;
+               hint->joinrelids = bms_copy(join_relids);
+               hint->inner_nrels = bms_num_members(inner_relids);
+               hint->inner_joinrelids = bms_copy(inner_relids);
+
+               hstate->join_hint_level[hint->nrels] =
+                       lappend(hstate->join_hint_level[hint->nrels], hint);
+       }
+       else
+       {
+               hint->inner_nrels = bms_num_members(inner_relids);
+               hint->inner_joinrelids = bms_copy(inner_relids);
+       }
+
+       return join_relids;
+}
+
+static Relids
+create_bms_of_relids(Hint *base, PlannerInfo *root, List *initial_rels,
+               int nrels, char **relnames)
+{
+       int             relid;
+       Relids  relids = NULL;
+       int             j;
+       char   *relname;
+
+       for (j = 0; j < nrels; j++)
+       {
+               relname = relnames[j];
+
+               relid = find_relid_aliasname(root, relname, initial_rels,
+                                                                        base->hint_str);
+
+               if (relid == -1)
+                       base->state = HINT_STATE_ERROR;
+
+               /*
+                * the aliasname is not found(relid == 0) or same aliasname was used
+                * multiple times in a query(relid == -1)
+                */
+               if (relid <= 0)
+               {
+                       relids = NULL;
+                       break;
+               }
+               if (bms_is_member(relid, relids))
+               {
+                       hint_ereport(base->hint_str,
+                                                ("Relation name \"%s\" is duplicated.", relname));
+                       base->state = HINT_STATE_ERROR;
+                       break;
+               }
+
+               relids = bms_add_member(relids, relid);
+       }
+       return relids;
+}
 /*
  * Transform join method hint into handy form.
  *
@@ -2095,16 +3677,17 @@ find_join_hint(Relids joinrelids)
  *   - add join method hints which are necessary to enforce join order
  *     specified by Leading hint
  */
-static void
+static bool
 transform_join_hints(HintState *hstate, PlannerInfo *root, int nbaserel,
                List *initial_rels, JoinMethodHint **join_method_hints)
 {
        int                             i;
        int                             relid;
-       LeadingHint        *lhint;
        Relids                  joinrelids;
        int                             njoinrels;
        ListCell           *l;
+       char               *relname;
+       LeadingHint        *lhint = NULL;
 
        /*
         * Create bitmap of relids from alias names for each join method hint.
@@ -2113,53 +3696,92 @@ transform_join_hints(HintState *hstate, PlannerInfo *root, int nbaserel,
        for (i = 0; i < hstate->num_hints[HINT_TYPE_JOIN_METHOD]; i++)
        {
                JoinMethodHint *hint = hstate->join_hints[i];
-               int     j;
 
                if (!hint_state_enabled(hint) || hint->nrels > nbaserel)
                        continue;
 
-               bms_free(hint->joinrelids);
-               hint->joinrelids = NULL;
+               hint->joinrelids = create_bms_of_relids(&(hint->base), root,
+                                                                        initial_rels, hint->nrels, hint->relnames);
+
+               if (hint->joinrelids == NULL || hint->base.state == HINT_STATE_ERROR)
+                       continue;
+
+               hstate->join_hint_level[hint->nrels] =
+                       lappend(hstate->join_hint_level[hint->nrels], hint);
+       }
+
+       /*
+        * Create bitmap of relids from alias names for each rows hint.
+        * Bitmaps are more handy than strings in join searching.
+        */
+       for (i = 0; i < hstate->num_hints[HINT_TYPE_ROWS]; i++)
+       {
+               RowsHint *hint = hstate->rows_hints[i];
+
+               if (!hint_state_enabled(hint) || hint->nrels > nbaserel)
+                       continue;
+
+               hint->joinrelids = create_bms_of_relids(&(hint->base), root,
+                                                                        initial_rels, hint->nrels, hint->relnames);
+       }
+
+       /* Do nothing if no Leading hint was supplied. */
+       if (hstate->num_hints[HINT_TYPE_LEADING] == 0)
+               return false;
+
+       /*
+        * Decide whether to use Leading hint
+        */
+       for (i = 0; i < hstate->num_hints[HINT_TYPE_LEADING]; i++)
+       {
+               LeadingHint        *leading_hint = (LeadingHint *)hstate->leading_hint[i];
+               Relids                  relids;
+
+               if (leading_hint->base.state == HINT_STATE_ERROR)
+                       continue;
+
                relid = 0;
-               for (j = 0; j < hint->nrels; j++)
+               relids = NULL;
+
+               foreach(l, leading_hint->relations)
                {
-                       char   *relname = hint->relnames[j];
+                       relname = (char *)lfirst(l);;
 
                        relid = find_relid_aliasname(root, relname, initial_rels,
-                                                                                hint->base.hint_str);
-
+                                                                                leading_hint->base.hint_str);
                        if (relid == -1)
-                               hint->base.state = HINT_STATE_ERROR;
+                               leading_hint->base.state = HINT_STATE_ERROR;
 
                        if (relid <= 0)
                                break;
 
-                       if (bms_is_member(relid, hint->joinrelids))
+                       if (bms_is_member(relid, relids))
                        {
-                               hint_ereport(hint->base.hint_str,
+                               hint_ereport(leading_hint->base.hint_str,
                                                         ("Relation name \"%s\" is duplicated.", relname));
-                               hint->base.state = HINT_STATE_ERROR;
+                               leading_hint->base.state = HINT_STATE_ERROR;
                                break;
                        }
 
-                       hint->joinrelids = bms_add_member(hint->joinrelids, relid);
+                       relids = bms_add_member(relids, relid);
                }
 
-               if (relid <= 0 || hint->base.state == HINT_STATE_ERROR)
+               if (relid <= 0 || leading_hint->base.state == HINT_STATE_ERROR)
                        continue;
 
-               hstate->join_hint_level[hint->nrels] =
-                       lappend(hstate->join_hint_level[hint->nrels], hint);
+               if (lhint != NULL)
+               {
+                       hint_ereport(lhint->base.hint_str,
+                                ("Conflict %s hint.", HintTypeName[lhint->base.type]));
+                       lhint->base.state = HINT_STATE_DUPLICATION;
+               }
+               leading_hint->base.state = HINT_STATE_USED;
+               lhint = leading_hint;
        }
 
-       /* Do nothing if no Leading hint was supplied. */
-       if (hstate->num_hints[HINT_TYPE_LEADING] == 0)
-               return;
-
-       /* Do nothing if Leading hint is invalid. */
-       lhint = hstate->leading_hint;
-       if (!hint_state_enabled(lhint))
-               return;
+       /* check to exist Leading hint marked with 'used'. */
+       if (lhint == NULL)
+               return false;
 
        /*
         * We need join method hints which fit specified join order in every join
@@ -2174,91 +3796,125 @@ transform_join_hints(HintState *hstate, PlannerInfo *root, int nbaserel,
         */
        joinrelids = NULL;
        njoinrels = 0;
-       foreach(l, lhint->relations)
+       if (lhint->outer_inner == NULL)
        {
-               char   *relname = (char *)lfirst(l);
-               JoinMethodHint *hint;
-
-               /*
-                * Find relid of the relation which has given name.  If we have the
-                * name given in Leading hint multiple times in the join, nothing to
-                * do.
-                */
-               relid = find_relid_aliasname(root, relname, initial_rels,
-                                                                        hstate->hint_str);
-               if (relid == -1)
+               foreach(l, lhint->relations)
                {
-                       bms_free(joinrelids);
-                       return;
-               }
-               if (relid == 0)
-                       continue;
+                       JoinMethodHint *hint;
 
-               /* Found relid must not be in joinrelids. */
-               if (bms_is_member(relid, joinrelids))
-               {
-                       hint_ereport(lhint->base.hint_str,
-                                                ("Relation name \"%s\" is duplicated.", relname));
-                       lhint->base.state = HINT_STATE_ERROR;
-                       bms_free(joinrelids);
-                       return;
-               }
+                       relname = (char *)lfirst(l);
 
-               /* Create bitmap of relids for current join level. */
-               joinrelids = bms_add_member(joinrelids, relid);
-               njoinrels++;
+                       /*
+                        * Find relid of the relation which has given name.  If we have the
+                        * name given in Leading hint multiple times in the join, nothing to
+                        * do.
+                        */
+                       relid = find_relid_aliasname(root, relname, initial_rels,
+                                                                                hstate->hint_str);
 
-               /* We never have join method hint for single relation. */
-               if (njoinrels < 2)
-                       continue;
+                       /* Create bitmap of relids for current join level. */
+                       joinrelids = bms_add_member(joinrelids, relid);
+                       njoinrels++;
+
+                       /* We never have join method hint for single relation. */
+                       if (njoinrels < 2)
+                               continue;
 
-               /*
-                * If we don't have join method hint, create new one for the
-                * join combination with all join methods are enabled.
-                */
-               hint = find_join_hint(joinrelids);
-               if (hint == NULL)
-               {
                        /*
-                        * Here relnames is not set, since Relids bitmap is sufficient to
-                        * control paths of this query afterward.
+                        * If we don't have join method hint, create new one for the
+                        * join combination with all join methods are enabled.
                         */
-                       hint = (JoinMethodHint *) JoinMethodHintCreate(lhint->base.hint_str,
-                                                                                                                  HINT_LEADING,
-                                                                                                                 HINT_KEYWORD_LEADING);
-                       hint->base.state = HINT_STATE_USED;
-                       hint->nrels = njoinrels;
-                       hint->enforce_mask = ENABLE_ALL_JOIN;
-                       hint->joinrelids = bms_copy(joinrelids);
+                       hint = find_join_hint(joinrelids);
+                       if (hint == NULL)
+                       {
+                               /*
+                                * Here relnames is not set, since Relids bitmap is sufficient
+                                * to control paths of this query afterward.
+                                */
+                               hint = (JoinMethodHint *) JoinMethodHintCreate(
+                                                                                       lhint->base.hint_str,
+                                                                                       HINT_LEADING,
+                                                                                       HINT_KEYWORD_LEADING);
+                               hint->base.state = HINT_STATE_USED;
+                               hint->nrels = njoinrels;
+                               hint->enforce_mask = ENABLE_ALL_JOIN;
+                               hint->joinrelids = bms_copy(joinrelids);
+                       }
+
+                       join_method_hints[njoinrels] = hint;
+
+                       if (njoinrels >= nbaserel)
+                               break;
                }
+               bms_free(joinrelids);
 
-               join_method_hints[njoinrels] = hint;
+               if (njoinrels < 2)
+                       return false;
 
-               if (njoinrels >= nbaserel)
-                       break;
+               /*
+                * Delete all join hints which have different combination from Leading
+                * hint.
+                */
+               for (i = 2; i <= njoinrels; i++)
+               {
+                       list_free(hstate->join_hint_level[i]);
+
+                       hstate->join_hint_level[i] = lappend(NIL, join_method_hints[i]);
+               }
        }
+       else
+       {
+               joinrelids = OuterInnerJoinCreate(lhint->outer_inner,
+                                                                                 lhint,
+                                          root,
+                                          initial_rels,
+                                                                                 hstate,
+                                                                                 nbaserel);
 
-       bms_free(joinrelids);
+               njoinrels = bms_num_members(joinrelids);
+               Assert(njoinrels >= 2);
 
-       if (njoinrels < 2)
-               return;
+               /*
+                * Delete all join hints which have different combination from Leading
+                * hint.
+                */
+               for (i = 2;i <= njoinrels; i++)
+               {
+                       if (hstate->join_hint_level[i] != NIL)
+                       {
+                               ListCell *prev = NULL;
+                               ListCell *next = NULL;
+                               for(l = list_head(hstate->join_hint_level[i]); l; l = next)
+                               {
 
-       /*
-        * Delete all join hints which have different combination from Leading
-        * hint.
-        */
-       for (i = 2; i <= njoinrels; i++)
-       {
-               list_free(hstate->join_hint_level[i]);
+                                       JoinMethodHint *hint = (JoinMethodHint *)lfirst(l);
+
+                                       next = lnext(l);
+
+                                       if (hint->inner_nrels == 0 &&
+                                               !(bms_intersect(hint->joinrelids, joinrelids) == NULL ||
+                                                 bms_equal(bms_union(hint->joinrelids, joinrelids),
+                                                 hint->joinrelids)))
+                                       {
+                                               hstate->join_hint_level[i] =
+                                                       list_delete_cell(hstate->join_hint_level[i], l,
+                                                                                        prev);
+                                       }
+                                       else
+                                               prev = l;
+                               }
+                       }
+               }
 
-               hstate->join_hint_level[i] = lappend(NIL, join_method_hints[i]);
+               bms_free(joinrelids);
        }
 
        if (hint_state_enabled(lhint))
+       {
                set_join_config_options(DISABLE_ALL_JOIN, current_hint->context);
-
-       lhint->base.state = HINT_STATE_USED;
-
+               return true;
+       }
+       return false;
 }
 
 /*
@@ -2272,11 +3928,7 @@ static void
 set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
 {
        /* Consider sequential scan */
-#if PG_VERSION_NUM >= 90200
        add_path(rel, create_seqscan_path(root, rel, NULL));
-#else
-       add_path(rel, create_seqscan_path(root, rel));
-#endif
 
        /* Consider index scans */
        create_index_paths(root, rel);
@@ -2315,7 +3967,7 @@ rebuild_scan_path(HintState *hstate, PlannerInfo *root, int level,
                 * planner if scan method hint is not specified, otherwise use
                 * specified hints and mark the hint as used.
                 */
-               if ((hint = find_scan_hint(root, rel)) == NULL)
+               if ((hint = find_scan_hint(root, rel->relid, rel)) == NULL)
                        set_scan_config_options(hstate->init_scan_mask,
                                                                        hstate->context);
                else
@@ -2335,6 +3987,8 @@ rebuild_scan_path(HintState *hstate, PlannerInfo *root, int level,
                {
                        set_plain_rel_pathlist(root, rel, rte);
                }
+
+               set_cheapest(rel);
        }
 
        /*
@@ -2364,21 +4018,88 @@ make_join_rel_wrapper(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
        if (!hint)
                return pg_hint_plan_make_join_rel(root, rel1, rel2);
 
-       save_nestlevel = NewGUCNestLevel();
+       if (hint->inner_nrels == 0)
+       {
+               save_nestlevel = NewGUCNestLevel();
 
-       set_join_config_options(hint->enforce_mask, current_hint->context);
+               set_join_config_options(hint->enforce_mask, current_hint->context);
 
-       rel = pg_hint_plan_make_join_rel(root, rel1, rel2);
-       hint->base.state = HINT_STATE_USED;
+               rel = pg_hint_plan_make_join_rel(root, rel1, rel2);
+               hint->base.state = HINT_STATE_USED;
 
-       /*
-        * Restore the GUC variables we set above.
-        */
-       AtEOXact_GUC(true, save_nestlevel);
+               /*
+                * Restore the GUC variables we set above.
+                */
+               AtEOXact_GUC(true, save_nestlevel);
+       }
+       else
+               rel = pg_hint_plan_make_join_rel(root, rel1, rel2);
 
        return rel;
 }
 
+/*
+ * TODO : comment
+ */
+static void
+add_paths_to_joinrel_wrapper(PlannerInfo *root,
+                                                        RelOptInfo *joinrel,
+                                                        RelOptInfo *outerrel,
+                                                        RelOptInfo *innerrel,
+                                                        JoinType jointype,
+                                                        SpecialJoinInfo *sjinfo,
+                                                        List *restrictlist)
+{
+       ScanMethodHint *scan_hint = NULL;
+       Relids                  joinrelids;
+       JoinMethodHint *join_hint;
+       int                             save_nestlevel;
+
+       if ((scan_hint = find_scan_hint(root, innerrel->relid, innerrel)) != NULL)
+       {
+               set_scan_config_options(scan_hint->enforce_mask, current_hint->context);
+               scan_hint->base.state = HINT_STATE_USED;
+       }
+
+       joinrelids = bms_union(outerrel->relids, innerrel->relids);
+       join_hint = find_join_hint(joinrelids);
+       bms_free(joinrelids);
+
+       if (join_hint && join_hint->inner_nrels != 0)
+       {
+               save_nestlevel = NewGUCNestLevel();
+
+               if (bms_equal(join_hint->inner_joinrelids, innerrel->relids))
+               {
+
+                       set_join_config_options(join_hint->enforce_mask,
+                                                                       current_hint->context);
+
+                       add_paths_to_joinrel(root, joinrel, outerrel, innerrel, jointype,
+                                                                sjinfo, restrictlist);
+                       join_hint->base.state = HINT_STATE_USED;
+               }
+               else
+               {
+                       set_join_config_options(DISABLE_ALL_JOIN, current_hint->context);
+                       add_paths_to_joinrel(root, joinrel, outerrel, innerrel, jointype,
+                                                                sjinfo, restrictlist);
+               }
+
+               /*
+                * Restore the GUC variables we set above.
+                */
+               AtEOXact_GUC(true, save_nestlevel);
+       }
+       else
+               add_paths_to_joinrel(root, joinrel, outerrel, innerrel, jointype,
+                                                        sjinfo, restrictlist);
+
+       if (scan_hint != NULL)
+               set_scan_config_options(current_hint->init_scan_mask,
+                                                               current_hint->context);
+}
+
 static int
 get_num_baserels(List *initial_rels)
 {
@@ -2407,16 +4128,18 @@ static RelOptInfo *
 pg_hint_plan_join_search(PlannerInfo *root, int levels_needed,
                                                 List *initial_rels)
 {
-       JoinMethodHint **join_method_hints;
-       int                     nbaserel;
-       RelOptInfo *rel;
-       int                     i;
+       JoinMethodHint    **join_method_hints;
+       int                                     nbaserel;
+       RelOptInfo                 *rel;
+       int                                     i;
+       bool                            leading_hint_enable;
 
        /*
         * Use standard planner (or geqo planner) if pg_hint_plan is disabled or no
-        * valid hint is supplied.
+        * valid hint is supplied or current nesting depth is nesting depth of SPI
+        * calls.
         */
-       if (!current_hint)
+       if (!current_hint || hint_inhibit_level > 0)
        {
                if (prev_join_search)
                        return (*prev_join_search) (root, levels_needed, initial_rels);
@@ -2440,8 +4163,8 @@ pg_hint_plan_join_search(PlannerInfo *root, int levels_needed,
        current_hint->join_hint_level = palloc0(sizeof(List *) * (nbaserel + 1));
        join_method_hints = palloc0(sizeof(JoinMethodHint *) * (nbaserel + 1));
 
-       transform_join_hints(current_hint, root, nbaserel, initial_rels,
-                                                join_method_hints);
+       leading_hint_enable = transform_join_hints(current_hint, root, nbaserel,
+                                                                                          initial_rels, join_method_hints);
 
        rel = pg_hint_plan_standard_join_search(root, levels_needed, initial_rels);
 
@@ -2457,8 +4180,7 @@ pg_hint_plan_join_search(PlannerInfo *root, int levels_needed,
        pfree(current_hint->join_hint_level);
        pfree(join_method_hints);
 
-       if (current_hint->num_hints[HINT_TYPE_LEADING] > 0 &&
-               hint_state_enabled(current_hint->leading_hint))
+       if (leading_hint_enable)
                set_join_config_options(current_hint->init_join_mask,
                                                                current_hint->context);
 
@@ -2476,15 +4198,11 @@ static void
 set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
                                 Index rti, RangeTblEntry *rte)
 {
-#if PG_VERSION_NUM >= 90200
        if (IS_DUMMY_REL(rel))
        {
                /* We already proved the relation empty, so nothing more to do */
        }
        else if (rte->inh)
-#else
-       if (rte->inh)
-#endif
        {
                /* It's an "append relation", process accordingly */
                set_append_rel_pathlist(root, rel, rti, rte);
@@ -2506,6 +4224,42 @@ set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
        }
 }
 
+/*
+ * stmt_beg callback is called when each query in PL/pgSQL function is about
+ * to be executed.  At that timing, we save query string in the global variable
+ * plpgsql_query_string to use it in planner hook.  It's safe to use one global
+ * variable for the purpose, because its content is only necessary until
+ * planner hook is called for the query, so recursive PL/pgSQL function calls
+ * don't harm this mechanism.
+ */
+static void
+pg_hint_plan_plpgsql_stmt_beg(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
+{
+       plpgsql_recurse_level++;
+}
+
+/*
+ * stmt_end callback is called then each query in PL/pgSQL function has
+ * finished.  At that timing, we clear plpgsql_query_string to tell planner
+ * hook that next call is not for a query written in PL/pgSQL block.
+ */
+static void
+pg_hint_plan_plpgsql_stmt_end(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
+{
+       plpgsql_recurse_level--;
+}
+
+void plpgsql_query_erase_callback(ResourceReleasePhase phase,
+                                                                 bool isCommit,
+                                                                 bool isTopLevel,
+                                                                 void *arg)
+{
+       if (!isTopLevel || phase != RESOURCE_RELEASE_AFTER_LOCKS)
+               return;
+       /* Cancel plpgsql nest level*/
+       plpgsql_recurse_level = 0;
+}
+
 #define standard_join_search pg_hint_plan_standard_join_search
 #define join_search_one_level pg_hint_plan_join_search_one_level
 #define make_join_rel make_join_rel_wrapper
@@ -2513,16 +4267,7 @@ set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
 
 #undef make_join_rel
 #define make_join_rel pg_hint_plan_make_join_rel
-#define add_paths_to_joinrel(root, joinrel, outerrel, innerrel, jointype, sjinfo, restrictlist) \
-do { \
-       ScanMethodHint *hint = NULL; \
-       if ((hint = find_scan_hint((root), (innerrel))) != NULL) \
-       { \
-               set_scan_config_options(hint->enforce_mask, current_hint->context); \
-               hint->base.state = HINT_STATE_USED; \
-       } \
-       add_paths_to_joinrel((root), (joinrel), (outerrel), (innerrel), (jointype), (sjinfo), (restrictlist)); \
-       if (hint != NULL) \
-               set_scan_config_options(current_hint->init_scan_mask, current_hint->context); \
-} while(0)
+#define add_paths_to_joinrel add_paths_to_joinrel_wrapper
 #include "make_join_rel.c"
+
+#include "pg_stat_statements.c"