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[pghintplan/pg_hint_plan.git] / pg_hint_plan.c
index e6f2127..db6254c 100644 (file)
@@ -4,7 +4,7 @@
  *               do instructions or hints to the planner using C-style block comments
  *               of the SQL.
  *
- * Copyright (c) 2012-2013, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
+ * Copyright (c) 2012-2014, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
  *
  *-------------------------------------------------------------------------
  */
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/syscache.h"
-#if PG_VERSION_NUM >= 90200
+#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   "+"
@@ -64,11 +68,9 @@ PG_MODULE_MAGIC;
 #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"
@@ -77,12 +79,14 @@ 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)), \
+       ereport(pg_hint_plan_message_level, \
+                       (errhidestmt(hidestmt), \
+                        errmsg("pg_hint_plan%s: hint syntax error at or near \"%s\"", qnostr, (str)), \
                         errdetail detail))
 
 #define skip_space(str) \
@@ -95,9 +99,7 @@ enum
        ENABLE_INDEXSCAN = 0x02,
        ENABLE_BITMAPSCAN = 0x04,
        ENABLE_TIDSCAN = 0x08,
-#if PG_VERSION_NUM >= 90200
        ENABLE_INDEXONLYSCAN = 0x10
-#endif
 } SCAN_TYPE_BITS;
 
 enum
@@ -107,14 +109,9 @@ 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
@@ -132,11 +129,9 @@ typedef enum HintKeyword
        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,
@@ -145,6 +140,7 @@ typedef enum HintKeyword
        HINT_KEYWORD_NOHASHJOIN,
        HINT_KEYWORD_LEADING,
        HINT_KEYWORD_SET,
+       HINT_KEYWORD_ROWS,
        HINT_KEYWORD_UNRECOGNIZED
 } HintKeyword;
 
@@ -155,26 +151,28 @@ typedef Hint *(*HintCreateFunction) (const char *hint_str,
                                                                         const char *keyword,
                                                                         HintKeyword hint_keyword);
 typedef void (*HintDeleteFunction) (Hint *hint);
-typedef void (*HintDescFunction) (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 */
@@ -190,6 +188,9 @@ 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 char qnostr[32];
+
 /* common data for all hints. */
 struct Hint
 {
@@ -261,6 +262,26 @@ 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.
  */
@@ -280,9 +301,8 @@ struct HintState
        ScanMethodHint **scan_hints;            /* parsed scan hints */
        int                             init_scan_mask;         /* initial value scan parameter */
        Index                   parent_relid;           /* inherit parent table relid */
-       Oid                             parent_rel_oid;     /* inherit parent table relid */
        ScanMethodHint *parent_hint;            /* inherit parent table scan hint */
-       List               *parent_index_infos; /* infomation of inherit parent table's
+       List               *parent_index_infos; /* information of inherit parent table's
                                                                                 * index */
 
        /* for join method hints */
@@ -296,6 +316,9 @@ struct HintState
        /* 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 */
 };
 
 /*
@@ -316,10 +339,10 @@ static void push_hint(HintState *hstate);
 static void pop_hint(void);
 
 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,
@@ -332,31 +355,40 @@ 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 ScanMethodHintDesc(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 JoinMethodHintDesc(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 LeadingHintDesc(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 SetHintDesc(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);
 
@@ -375,22 +407,38 @@ 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_message_level = INFO;
+/* Default is off, to keep backward compatibility. */
+static bool    pg_hint_plan_enable_hint_table = false;
+
+/* Internal static variables. */
+static bool    hidestmt = false;                               /* Allow or inhibit STATEMENT: output */
+
+static int plpgsql_recurse_level = 0;          /* PLpgSQL recursion level            */
+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},
@@ -411,6 +459,22 @@ 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 planner_hook_type prev_planner = NULL;
@@ -444,12 +508,10 @@ static const HintParser parsers[] = {
        {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},
@@ -458,32 +520,46 @@ 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,
@@ -493,7 +569,7 @@ _PG_init(void)
        DefineCustomEnumVariable("pg_hint_plan.parse_messages",
                                                         "Message level of parse errors.",
                                                         NULL,
-                                                        &pg_hint_plan_parse_messages,
+                                                        &pg_hint_plan_message_level,
                                                         INFO,
                                                         parse_messages_level_options,
                                                         PGC_USERSET,
@@ -502,6 +578,29 @@ _PG_init(void)
                                                         NULL,
                                                         NULL);
 
+       DefineCustomEnumVariable("pg_hint_plan.message_level",
+                                                        "Message level of debug messages.",
+                                                        NULL,
+                                                        &pg_hint_plan_message_level,
+                                                        INFO,
+                                                        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;
@@ -511,6 +610,12 @@ _PG_init(void)
        get_relation_info_hook = pg_hint_plan_get_relation_info;
        prev_join_search = join_search_hook;
        join_search_hook = pg_hint_plan_join_search;
+
+       /* setup PL/pgSQL plugin hook */
+       var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
+       *var_ptr = &plugin_funcs;
+
+       RegisterResourceReleaseCallback(plpgsql_query_erase_callback, NULL);
 }
 
 /*
@@ -520,11 +625,17 @@ _PG_init(void)
 void
 _PG_fini(void)
 {
+       PLpgSQL_plugin  **var_ptr;
+
        /* Uninstall hooks. */
        ProcessUtility_hook = prev_ProcessUtility;
        planner_hook = prev_planner;
        get_relation_info_hook = prev_get_relation_info;
        join_search_hook = prev_join_search;
+
+       /* uninstall PL/pgSQL plugin hook */
+       var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
+       *var_ptr = NULL;
 }
 
 /*
@@ -685,6 +796,54 @@ 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)
 {
@@ -699,7 +858,6 @@ HintStateCreate(void)
        hstate->scan_hints = NULL;
        hstate->init_scan_mask = 0;
        hstate->parent_relid = 0;
-       hstate->parent_rel_oid = InvalidOid;
        hstate->parent_hint = NULL;
        hstate->parent_index_infos = NIL;
        hstate->join_hints = NULL;
@@ -708,6 +866,7 @@ HintStateCreate(void)
        hstate->leading_hint = NULL;
        hstate->context = superuser() ? PGC_SUSET : PGC_USERSET;
        hstate->set_hints = NULL;
+       hstate->rows_hints = NULL;
 
        return hstate;
 }
@@ -763,7 +922,7 @@ quote_value(StringInfo buf, const char *value)
 }
 
 static void
-ScanMethodHintDesc(ScanMethodHint *hint, StringInfo buf)
+ScanMethodHintDesc(ScanMethodHint *hint, StringInfo buf, bool nolf)
 {
        ListCell   *l;
 
@@ -777,11 +936,13 @@ ScanMethodHintDesc(ScanMethodHint *hint, StringInfo buf)
                        quote_value(buf, (char *) lfirst(l));
                }
        }
-       appendStringInfoString(buf, ")\n");
+       appendStringInfoString(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
 }
 
 static void
-JoinMethodHintDesc(JoinMethodHint *hint, StringInfo buf)
+JoinMethodHintDesc(JoinMethodHint *hint, StringInfo buf, bool nolf)
 {
        int     i;
 
@@ -795,8 +956,9 @@ JoinMethodHintDesc(JoinMethodHint *hint, StringInfo buf)
                        quote_value(buf, hint->relnames[i]);
                }
        }
-       appendStringInfoString(buf, ")\n");
-
+       appendStringInfoString(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
 }
 
 static void
@@ -827,7 +989,7 @@ OuterInnerDesc(OuterInnerRels *outer_inner, StringInfo buf)
 }
 
 static void
-LeadingHintDesc(LeadingHint *hint, StringInfo buf)
+LeadingHintDesc(LeadingHint *hint, StringInfo buf, bool nolf)
 {
        appendStringInfo(buf, "%s(", HINT_LEADING);
        if (hint->outer_inner == NULL)
@@ -850,11 +1012,13 @@ LeadingHintDesc(LeadingHint *hint, StringInfo buf)
        else
                OuterInnerDesc(hint->outer_inner, buf);
 
-       appendStringInfoString(buf, ")\n");
+       appendStringInfoString(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
 }
 
 static void
-SetHintDesc(SetHint *hint, StringInfo buf)
+SetHintDesc(SetHint *hint, StringInfo buf, bool nolf)
 {
        bool            is_first = true;
        ListCell   *l;
@@ -869,27 +1033,58 @@ SetHintDesc(SetHint *hint, StringInfo buf)
 
                quote_value(buf, (char *) lfirst(l));
        }
-       appendStringInfo(buf, ")\n");
+       appendStringInfo(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
+}
+
+static void
+RowsHintDesc(RowsHint *hint, StringInfo buf, bool nolf)
+{
+       int     i;
+
+       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]);
+               }
+       }
+       appendStringInfo(buf, " %s", hint->rows_str);
+       appendStringInfoString(buf, ")");
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
 }
 
 /*
- * Append string which repserents all hints in a given state to buf, with
+ * 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)
+                                  HintStatus state, bool nolf)
 {
-       int     i;
+       int     i, nshown;
+
+       appendStringInfo(buf, "%s:", title);
+       if (!nolf)
+               appendStringInfoChar(buf, '\n');
 
-       appendStringInfo(buf, "%s:\n", title);
+       nshown = 0;
        for (i = 0; i < hstate->nall_hints; i++)
        {
                if (hstate->all_hints[i]->state != state)
                        continue;
 
-               hstate->all_hints[i]->desc_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)");
 }
 
 /*
@@ -909,16 +1104,43 @@ HintStateDump(HintState *hstate)
        initStringInfo(&buf);
 
        appendStringInfoString(&buf, "pg_hint_plan:\n");
-       desc_hint_in_state(hstate, &buf, "used hint", HINT_STATE_USED);
-       desc_hint_in_state(hstate, &buf, "not used hint", HINT_STATE_NOTUSED);
-       desc_hint_in_state(hstate, &buf, "duplication hint", HINT_STATE_DUPLICATION);
-       desc_hint_in_state(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);
 
        elog(LOG, "%s", buf.data);
 
        pfree(buf.data);
 }
 
+static void
+HintStateDump2(HintState *hstate)
+{
+       StringInfoData  buf;
+
+       if (!hstate)
+       {
+               elog(pg_hint_plan_message_level,
+                        "pg_hint_plan%s: HintStateDump: no hint", qnostr);
+               return;
+       }
+
+       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_message_level,
+                       (errhidestmt(true),
+                        errmsg("%s", buf.data)));
+
+       pfree(buf.data);
+}
+
 /*
  * compare functions
  */
@@ -969,6 +1191,24 @@ 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);
@@ -1234,9 +1474,7 @@ parse_parentheses(const char *str, List **name_list, HintKeyword keyword)
                skip_space(str);
 
                if (keyword == HINT_KEYWORD_INDEXSCANREGEXP ||
-#if PG_VERSION_NUM >= 90200
                        keyword == HINT_KEYWORD_INDEXONLYSCANREGEXP ||
-#endif
                        keyword == HINT_KEYWORD_BITMAPSCANREGEXP ||
                        keyword == HINT_KEYWORD_SET)
                {
@@ -1324,7 +1562,9 @@ parse_hints(HintState *hstate, Query *parse, const char *str)
 }
 
 
-/* search hint. */
+/* 
+ * Get hints from table by client-supplied query string and application name.
+ */
 static const char *
 get_hints_from_table(const char *client_query, const char *client_application)
 {
@@ -1336,7 +1576,6 @@ get_hints_from_table(const char *client_query, const char *client_application)
                "    OR application_name = '' ) "
                " ORDER BY application_name DESC";
        static SPIPlanPtr plan = NULL;
-       int             ret;
        char   *hints = NULL;
        Oid             argtypes[2] = { TEXTOID, TEXTOID };
        Datum   values[2];
@@ -1344,46 +1583,54 @@ get_hints_from_table(const char *client_query, const char *client_application)
        text   *qry;
        text   *app;
 
-       ret = SPI_connect();
-       if (ret != SPI_OK_CONNECT)
-               elog(ERROR, "pg_hint_plan: SPI_connect => %d", ret);
-
-       if (plan == NULL)
+       PG_TRY();
        {
-               SPIPlanPtr      p;
-               p = SPI_prepare(search_query, 2, argtypes);
-               if (p == NULL)
-                       elog(ERROR, "pg_hint_plan: SPI_prepare => %d", SPI_result);
-               plan = SPI_saveplan(p);
-               SPI_freeplan(p);
+               hint_inhibit_level++;
+       
+               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();
+       
+               hint_inhibit_level--;
        }
-
-       qry = cstring_to_text(client_query);
-       app = cstring_to_text(client_application);
-       values[0] = PointerGetDatum(qry);
-       values[1] = PointerGetDatum(app);
-
-       pg_hint_plan_enable_hint = false;
-       ret = SPI_execute_plan(plan, values, nulls, true, 1);
-       pg_hint_plan_enable_hint = true;
-       if (ret != SPI_OK_SELECT)
-               elog(ERROR, "pg_hint_plan: SPI_execute_plan => %d", ret);
-
-       if (SPI_processed > 0)
+       PG_CATCH();
        {
-               int              len;
-               char    *buf;
-
-               hints = pstrdup(SPI_getvalue(SPI_tuptable->vals[0],
-                                                                          SPI_tuptable->tupdesc, 1));
-               len = strlen(hints);
-               buf = SPI_palloc(len + 1);
-               memcpy(buf, hints, len);
-               buf[len] = '\0';
-               hints = buf;
+               hint_inhibit_level--;
+               PG_RE_THROW();
        }
-
-       SPI_finish();
+       PG_END_TRY();
 
        return hints;
 }
@@ -1396,7 +1643,15 @@ get_query_string(void)
 {
        const char *p;
 
-       if (stmt_name)
+       if (plpgsql_recurse_level > 0)
+       {
+               /*
+                * This is quite ugly but this is the only point I could find where
+                * we can get the query string.
+                */
+               p = (char*)error_context_stack->arg;
+       }
+       else if (stmt_name)
        {
                PreparedStatement  *entry;
 
@@ -1520,7 +1775,7 @@ create_hintstate(Query *parse, const char *hints)
 
        /*
         * 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++)
@@ -1558,6 +1813,8 @@ create_hintstate(Query *parse, const char *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;
 }
@@ -1588,10 +1845,8 @@ ScanMethodHintParse(ScanMethodHint *hint, HintState *hstate, Query *parse,
                if (length != 1 &&
                        hint_keyword != HINT_KEYWORD_INDEXSCAN &&
                        hint_keyword != HINT_KEYWORD_INDEXSCANREGEXP &&
-#if PG_VERSION_NUM >= 90200
                        hint_keyword != HINT_KEYWORD_INDEXONLYSCAN &&
                        hint_keyword != HINT_KEYWORD_INDEXONLYSCANREGEXP &&
-#endif
                        hint_keyword != HINT_KEYWORD_BITMAPSCAN &&
                        hint_keyword != HINT_KEYWORD_BITMAPSCANREGEXP)
                {
@@ -1646,7 +1901,6 @@ 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;
@@ -1657,7 +1911,6 @@ ScanMethodHintParse(ScanMethodHint *hint, HintState *hstate, Query *parse,
                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;
@@ -1853,6 +2106,97 @@ 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;
+
+       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 > 0)
+       {
+               ListCell   *l;
+               int                     i = 0;
+
+               /*
+                * 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
  */
@@ -1867,13 +2211,8 @@ 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();
        {
@@ -1884,10 +2223,12 @@ 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),
+                                errhidestmt(hidestmt),
+                                errmsg("%s", errdata->message),
+                                errdata->detail ? errdetail("%s", errdata->detail) : 0,
+                                errdata->hint ? errhint("%s", errdata->hint) : 0));
                FreeErrorData(errdata);
        }
        PG_END_TRY();
@@ -1913,7 +2254,7 @@ 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_message_level);
                if (result != 0)
                        hint->base.state = HINT_STATE_USED;
                else
@@ -1935,9 +2276,7 @@ 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
@@ -1947,9 +2286,7 @@ 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
@@ -1974,20 +2311,30 @@ set_join_config_options(unsigned char enforce_mask, GucContext context)
 
 static void
 pg_hint_plan_ProcessUtility(Node *parsetree, const char *queryString,
-                                                       ParamListInfo params, bool isTopLevel,
+                                                       ProcessUtilityContext context,
+                                                       ParamListInfo params,
                                                        DestReceiver *dest, char *completionTag)
 {
        Node                               *node;
 
-       if (!pg_hint_plan_enable_hint)
+       /* 
+        * Use standard planner if pg_hint_plan is disabled or current nesting 
+        * depth is nesting depth of SPI calls. 
+        */
+       if (!pg_hint_plan_enable_hint || hint_inhibit_level > 0)
        {
+               if (debug_level > 1)
+                       ereport(pg_hint_plan_message_level,
+                                       (errmsg ("pg_hint_plan: ProcessUtility:"
+                                                        " pg_hint_plan.enable_hint = off")));
                if (prev_ProcessUtility)
-                       (*prev_ProcessUtility) (parsetree, queryString, params,
-                                                                       isTopLevel, dest, completionTag);
+                       (*prev_ProcessUtility) (parsetree, queryString,
+                                                                       context, params,
+                                                                       dest, completionTag);
                else
-                       standard_ProcessUtility(parsetree, queryString, params,
-                                                                       isTopLevel, dest, completionTag);
-
+                       standard_ProcessUtility(parsetree, queryString,
+                                                                       context, params,
+                                                                       dest, completionTag);
                return;
        }
 
@@ -2021,7 +2368,7 @@ pg_hint_plan_ProcessUtility(Node *parsetree, const char *queryString,
                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.
@@ -2042,17 +2389,25 @@ pg_hint_plan_ProcessUtility(Node *parsetree, const char *queryString,
                        stmt_name = estmt->name;
                }
        }
-#endif
+
        if (stmt_name)
        {
+               if (debug_level > 1)
+                       ereport(pg_hint_plan_message_level,
+                                       (errmsg ("pg_hint_plan: ProcessUtility:"
+                                                        " stmt_name = \"%s\", statement=\"%s\"",
+                                                        stmt_name, queryString)));
+
                PG_TRY();
                {
                        if (prev_ProcessUtility)
-                               (*prev_ProcessUtility) (parsetree, queryString, params,
-                                                                               isTopLevel, dest, completionTag);
+                               (*prev_ProcessUtility) (parsetree, queryString,
+                                                                               context, params,
+                                                                               dest, completionTag);
                        else
-                               standard_ProcessUtility(parsetree, queryString, params,
-                                                                               isTopLevel, dest, completionTag);
+                               standard_ProcessUtility(parsetree, queryString,
+                                                                               context, params,
+                                                                               dest, completionTag);
                }
                PG_CATCH();
                {
@@ -2067,11 +2422,13 @@ pg_hint_plan_ProcessUtility(Node *parsetree, const char *queryString,
        }
 
        if (prev_ProcessUtility)
-               (*prev_ProcessUtility) (parsetree, queryString, params,
-                                                               isTopLevel, dest, completionTag);
-       else
-               standard_ProcessUtility(parsetree, queryString, params,
-                                                               isTopLevel, dest, completionTag);
+                       (*prev_ProcessUtility) (parsetree, queryString,
+                                                                       context, params,
+                                                                       dest, completionTag);
+               else
+                       standard_ProcessUtility(parsetree, queryString,
+                                                                       context, params,
+                                                                       dest, completionTag);
 }
 
 /*
@@ -2111,35 +2468,117 @@ pop_hint(void)
 static PlannedStmt *
 pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 {
-       const char         *hints;
+       const char         *hints = NULL;
        const char         *query;
+       char               *norm_query;
+       pgssJumbleState jstate;
+       int                             query_len;
        int                             save_nestlevel;
        PlannedStmt        *result;
        HintState          *hstate;
+       char                    msgstr[1024];
+
+       qnostr[0] = 0;
+       strcpy(msgstr, "");
+       if (debug_level > 1)
+               snprintf(qnostr, sizeof(qnostr), "[qno=0x%x]", qno++);
+       hidestmt = false;
 
        /*
-        * 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)
+       {
+               if (debug_level > 1)
+                       elog(pg_hint_plan_message_level,
+                                "pg_hint_plan%s: planner: enable_hint=%d,"
+                                " hint_inhibit_level=%d",
+                                qnostr, pg_hint_plan_enable_hint, hint_inhibit_level);
+               hidestmt = true;
+
                goto standard_planner_proc;
+       }
 
        /* Create hint struct from client-supplied query string. */
        query = get_query_string();
 
        /*
-        * get_hints_from_table
-        * TODO: replace "app1" with current application_name setting of the
-        * session.
-        * XXX: use something instead of debug_query_string?
+        * Create hintstate from hint specified for the query, if any.
+        *
+        * First we lookup hint in pg_hint.hints table by normalized query string,
+        * unless pg_hint_plan.enable_hint_table is OFF.
+        * This parameter provides option to avoid overhead of table lookup during
+        * planning.
+        *
+        * If no hint was found, then we try to get hint from special query comment.
         */
-       hints = get_hints_from_table(query, application_name);
-       elog(DEBUG1,
-                "pg_hint_plan: get_hints_from_table [%s][%s]=>[%s]",
-                query, application_name,
-                hints ? hints : "(none)");
+       if (pg_hint_plan_enable_hint_table)
+       {
+               /*
+                * Search hint information which is stored for the query and the
+                * application.  Query string is normalized before using in condition
+                * in order to allow fuzzy matching.
+                *
+                * XXX: normalizing code is copied from pg_stat_statements.c, so be
+                * careful when supporting PostgreSQL's version up.
+                */
+               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, parse);
+               /*
+                * generate_normalized_query() copies exact given query_len bytes, so we
+                * add 1 byte for null-termination here.  As comments on
+                * generate_normalized_query says, generate_normalized_query doesn't
+                * take care of null-terminate, but additional 1 byte ensures that '\0'
+                * byte in the source buffer to be copied into norm_query.
+                */
+               query_len = strlen(query) + 1;
+               norm_query = generate_normalized_query(&jstate,
+                                                                                          query,
+                                                                                          &query_len,
+                                                                                          GetDatabaseEncoding());
+               hints = get_hints_from_table(norm_query, application_name);
+               if (debug_level > 1)
+               {
+                       if (hints)
+                               snprintf(msgstr, 1024, "hints from table: \"%s\":"
+                                                " normalzed_query=\"%s\", application name =\"%s\"",
+                                                hints, norm_query, application_name);
+                       else
+                       {
+                               ereport(pg_hint_plan_message_level,
+                                               (errhidestmt(hidestmt),
+                                                errmsg("pg_hint_plan%s:"
+                                                               " no match found in table:"
+                                                               "  application name = \"%s\","
+                                                               " normalzed_query=\"%s\"",
+                                                               qnostr, application_name, norm_query)));
+                               hidestmt = true;
+                       }
+               }
+       }
        if (hints == NULL)
+       {
                hints = get_hints_from_comment(query);
+
+               if (debug_level > 1)
+               {
+                       snprintf(msgstr, 1024, "hints in comment=\"%s\"",
+                                        hints ? hints : "(none)");
+                       if (debug_level > 2 || 
+                               stmt_name || strcmp(query, debug_query_string))
+                               snprintf(msgstr + strlen(msgstr), 1024- strlen(msgstr), 
+                                        ", stmt=\"%s\", query=\"%s\", debug_query_string=\"%s\"",
+                                                stmt_name, query, debug_query_string);
+               }
+       }
+
        hstate = create_hintstate(parse, hints);
 
        /*
@@ -2168,10 +2607,8 @@ 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)
@@ -2179,6 +2616,15 @@ 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_message_level,
+                               (errhidestmt(hidestmt),
+                                errmsg("pg_hint_plan%s: planner: %s",
+                                               qnostr, msgstr))); 
+               hidestmt = true;
+       }
+
        /*
         * Use PG_TRY mechanism to recover GUC parameters and current_hint to the
         * state when this planner started when error occurred in planner.
@@ -2203,8 +2649,10 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
        PG_END_TRY();
 
        /* 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
@@ -2216,6 +2664,14 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
        return result;
 
 standard_planner_proc:
+       if (debug_level > 1)
+       {
+               ereport(pg_hint_plan_message_level,
+                               (errhidestmt(hidestmt),
+                                errmsg("pg_hint_plan%s: planner: no valid hint (%s)",
+                                               qnostr, msgstr)));
+               hidestmt = true;
+       }
        current_hint = NULL;
        if (prev_planner)
                return (*prev_planner) (parse, cursorOptions, boundParams);
@@ -2227,7 +2683,7 @@ standard_planner_proc:
  * 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;
@@ -2237,10 +2693,10 @@ 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)
@@ -2322,7 +2778,7 @@ 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)
@@ -2347,7 +2803,7 @@ delete_indexes(ScanMethodHint *hint, RelOptInfo *rel, Oid relationObjectId)
                        if (result)
                        {
                                use_index = true;
-                               if (pg_hint_plan_debug_print)
+                               if (debug_level > 0)
                                {
                                        appendStringInfoCharMacro(&buf, ' ');
                                        quote_value(&buf, indexname);
@@ -2464,7 +2920,7 @@ delete_indexes(ScanMethodHint *hint, RelOptInfo *rel, Oid relationObjectId)
                                                }
                                        }
 
-                                       /* Check to match the predicate's paraameter of index */
+                                       /* Check to match the predicate's parameter of index */
                                        if (p_info->indpred_str &&
                                                !heap_attisnull(ht_idx, Anum_pg_index_indpred))
                                        {
@@ -2473,7 +2929,7 @@ delete_indexes(ScanMethodHint *hint, RelOptInfo *rel, Oid relationObjectId)
                                                Datum       result;
 
                                                /*
-                                                * to change the predicate's parabeter of child's
+                                                * to change the predicate's parameter of child's
                                                 * index to strings
                                                 */
                                                predDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
@@ -2506,7 +2962,7 @@ delete_indexes(ScanMethodHint *hint, RelOptInfo *rel, Oid relationObjectId)
                                use_index = true;
 
                                /* to log the candidate of index */
-                               if (pg_hint_plan_debug_print)
+                               if (debug_level > 0)
                                {
                                        appendStringInfoCharMacro(&buf, ' ');
                                        quote_value(&buf, indexname);
@@ -2524,7 +2980,7 @@ 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;
@@ -2582,7 +3038,7 @@ get_parent_index_info(Oid indexoid, Oid relid)
        }
 
        /*
-        * to check to match the expression's paraameter of index with child indexes
+        * 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))
@@ -2602,7 +3058,7 @@ get_parent_index_info(Oid indexoid, Oid relid)
        }
 
        /*
-        * to check to match the predicate's paraameter of index with child indexes
+        * 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))
@@ -2630,104 +3086,191 @@ 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_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;
-               current_hint->parent_rel_oid = relationObjectId;
+               if (debug_level > 1)
+                       ereport(pg_hint_plan_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;
        }
-       else if (current_hint->parent_relid != 0)
+
+       /* Find the parent for this relation */
+       foreach (l, root->append_rel_list)
        {
-               /*
-                * 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.
-                */
-               ListCell   *l;
+               AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
 
-               /* append_rel_list contains all append rels; ignore others */
-               foreach(l, root->append_rel_list)
+               if (appinfo->child_relid == rel->relid)
                {
-                       AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
-
-                       /* This rel is child table. */
-                       if (appinfo->parent_relid == current_hint->parent_relid &&
-                               appinfo->child_relid == rel->relid)
-                       {
-                               if (current_hint->parent_hint)
-                                       delete_indexes(current_hint->parent_hint, rel,
-                                                                  relationObjectId);
-
-                               return;
-                       }
+                       if (current_hint->parent_relid != appinfo->parent_relid)
+                               new_parent_relid = appinfo->parent_relid;
+                       break;
                }
-
-               /* This rel is not inherit table. */
-               current_hint->parent_relid = 0;
-               current_hint->parent_rel_oid = InvalidOid;
-               current_hint->parent_hint = NULL;
        }
 
-       /*
-        * 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)
+       if (!l)
        {
-               set_scan_config_options(current_hint->init_scan_mask,
-                                                               current_hint->context);
-               return;
+               /* This relation doesn't have a parent. Cancel current_hint. */
+               current_hint->parent_relid = 0;
+               current_hint->parent_hint = NULL;
        }
-       set_scan_config_options(hint->enforce_mask, current_hint->context);
-       hint->base.state = HINT_STATE_USED;
 
-       if (inhparent)
+       if (new_parent_relid > 0)
        {
-               Relation    relation;
-               List       *indexoidlist;
-               ListCell   *l;
-
-               current_hint->parent_hint = hint;
+               /*
+                * 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.
+                */
+               int scanmask = current_hint->init_scan_mask;
+               ScanMethodHint *parent_hint;
 
-               relation = heap_open(relationObjectId, NoLock);
-               indexoidlist = RelationGetIndexList(relation);
+               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);
 
-               foreach(l, indexoidlist)
+               if (parent_hint)
                {
-                       Oid         indexoid = lfirst_oid(l);
-                       char       *indexname = get_rel_name(indexoid);
-                       bool        use_index = false;
-                       ListCell   *lc;
-                       ParentIndexInfo *parent_index_info;
+                       scanmask = current_hint->parent_hint->enforce_mask;
+                       parent_hint->base.state = HINT_STATE_USED;
 
-                       foreach(lc, hint->indexnames)
+                       /* Resolve index name mask (if any) using the parent. */
+                       if (parent_hint->indexnames)
                        {
-                               if (RelnameCmp(&indexname, &lfirst(lc)) == 0)
+                               Oid                     parentrel_oid;
+                               Relation        parent_rel;
+
+                               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))
                                {
-                                       use_index = true;
-                                       break;
+                                       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);
                        }
-                       if (!use_index)
-                               continue;
-
-                       parent_index_info = get_parent_index_info(indexoid,
-                                                                                                         relationObjectId);
-                       current_hint->parent_index_infos =
-                               lappend(current_hint->parent_index_infos, parent_index_info);
                }
-               heap_close(relation, NoLock);
+                       
+               set_scan_config_options(scanmask, current_hint->context);
+       }
+
+       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_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;
        }
-       else
+
+       /* 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_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_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;
 }
 
 /*
@@ -2884,6 +3427,46 @@ OuterInnerJoinCreate(OuterInnerRels *outer_inner, LeadingHint *leading_hint,
        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.
  *
@@ -2911,43 +3494,33 @@ 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;
-               relid = 0;
-               for (j = 0; j < hint->nrels; j++)
-               {
-                       relname = hint->relnames[j];
+               hint->joinrelids = create_bms_of_relids(&(hint->base), root,
+                                                                        initial_rels, hint->nrels, hint->relnames);
 
-                       relid = find_relid_aliasname(root, relname, initial_rels,
-                                                                                hint->base.hint_str);
-
-                       if (relid == -1)
-                               hint->base.state = HINT_STATE_ERROR;
-
-                       if (relid <= 0)
-                               break;
+               if (hint->joinrelids == NULL || hint->base.state == HINT_STATE_ERROR)
+                       continue;
 
-                       if (bms_is_member(relid, hint->joinrelids))
-                       {
-                               hint_ereport(hint->base.hint_str,
-                                                        ("Relation name \"%s\" is duplicated.", relname));
-                               hint->base.state = HINT_STATE_ERROR;
-                               break;
-                       }
+               hstate->join_hint_level[hint->nrels] =
+                       lappend(hstate->join_hint_level[hint->nrels], hint);
+       }
 
-                       hint->joinrelids = bms_add_member(hint->joinrelids, relid);
-               }
+       /*
+        * 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 (relid <= 0 || hint->base.state == HINT_STATE_ERROR)
+               if (!hint_state_enabled(hint) || hint->nrels > nbaserel)
                        continue;
 
-               hstate->join_hint_level[hint->nrels] =
-                       lappend(hstate->join_hint_level[hint->nrels], hint);
+               hint->joinrelids = create_bms_of_relids(&(hint->base), root,
+                                                                        initial_rels, hint->nrels, hint->relnames);
        }
 
        /* Do nothing if no Leading hint was supplied. */
@@ -2955,7 +3528,7 @@ transform_join_hints(HintState *hstate, PlannerInfo *root, int nbaserel,
                return false;
 
        /*
-        * Decide to use Leading hint。
+        * Decide whether to use Leading hint
         */
        for (i = 0; i < hstate->num_hints[HINT_TYPE_LEADING]; i++)
        {
@@ -3153,11 +3726,7 @@ 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);
@@ -3196,7 +3765,7 @@ 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
@@ -3216,6 +3785,8 @@ rebuild_scan_path(HintState *hstate, PlannerInfo *root, int level,
                {
                        set_plain_rel_pathlist(root, rel, rte);
                }
+
+               set_cheapest(rel);
        }
 
        /*
@@ -3282,7 +3853,7 @@ add_paths_to_joinrel_wrapper(PlannerInfo *root,
        JoinMethodHint *join_hint;
        int                             save_nestlevel;
 
-       if ((scan_hint = find_scan_hint(root, innerrel)) != NULL)
+       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;
@@ -3363,9 +3934,10 @@ pg_hint_plan_join_search(PlannerInfo *root, int levels_needed,
 
        /*
         * 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);
@@ -3424,15 +3996,11 @@ 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);
@@ -3454,6 +4022,42 @@ 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 (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
@@ -3463,3 +4067,5 @@ set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
 #define make_join_rel pg_hint_plan_make_join_rel
 #define add_paths_to_joinrel add_paths_to_joinrel_wrapper
 #include "make_join_rel.c"
+
+#include "pg_stat_statements.c"