OSDN Git Service

Fix a bug that index restriction by name doesn't work for UPDATEs on
[pghintplan/pg_hint_plan.git] / pg_hint_plan.c
index 6a94125..17753c2 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 "catalog/pg_class.h"
-#endif
 
+#include "executor/spi.h"
+#include "catalog/pg_type.h"
+
+/*
+ * We have our own header file "plpgsql-9.1", which is necessary to support
+ * hints for queries in PL/pgSQL blocks, in pg_hint_plan source package,
+ * because PostgreSQL 9.1 doesn't provide the header file as a part of
+ * installation.  This header file is a copy of src/pl/plpgsql/src/plpgsql.h in
+ * PostgreSQL 9.1.9 source tree,
+ *
+ * On the other hand, 9.2 installation provides that header file for external
+ * modules, so we include the header in ordinary place.
+ */
 #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   "+"
@@ -63,11 +77,9 @@ 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"
@@ -76,6 +88,7 @@ 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
 
@@ -94,9 +107,7 @@ enum
        ENABLE_INDEXSCAN = 0x02,
        ENABLE_BITMAPSCAN = 0x04,
        ENABLE_TIDSCAN = 0x08,
-#if PG_VERSION_NUM >= 90200
        ENABLE_INDEXONLYSCAN = 0x10
-#endif
 } SCAN_TYPE_BITS;
 
 enum
@@ -106,14 +117,9 @@ 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
@@ -131,11 +137,9 @@ 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,
@@ -144,6 +148,7 @@ typedef enum HintKeyword
        HINT_KEYWORD_NOHASHJOIN,
        HINT_KEYWORD_LEADING,
        HINT_KEYWORD_SET,
+       HINT_KEYWORD_ROWS,
        HINT_KEYWORD_UNRECOGNIZED
 } HintKeyword;
 
@@ -160,20 +165,22 @@ 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 */
@@ -260,6 +267,26 @@ 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.
  */
@@ -279,9 +306,8 @@ 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 */
@@ -295,6 +321,9 @@ 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 */
 };
 
 /*
@@ -315,10 +344,10 @@ 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,
@@ -356,6 +385,15 @@ static void SetHintDesc(SetHint *hint, StringInfo buf);
 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);
+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);
 
@@ -374,20 +412,16 @@ 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_func_setup(PLpgSQL_execstate *estate,
-                                                                                 PLpgSQL_stmt *stmt);
 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,
@@ -397,6 +431,8 @@ static void pg_hint_plan_plpgsql_stmt_end(PLpgSQL_execstate *estate,
 static bool    pg_hint_plan_enable_hint = true;
 static bool    pg_hint_plan_debug_print = false;
 static int     pg_hint_plan_parse_messages = INFO;
+/* Default is off, to keep backward compatibility. */
+static bool    pg_hint_plan_enable_hint_table = false;
 
 static const struct config_enum_entry parse_messages_level_options[] = {
        {"debug", DEBUG2, true},
@@ -450,12 +486,10 @@ 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},
@@ -464,17 +498,36 @@ 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}
 };
 
-const char *hint_query_string = NULL;
-PLpgSQL_plugin  plugin_funcs = { };
+/*
+ * PL/pgSQL plugin for retrieving string representation of each query during
+ * function execution.
+ */
+const char *plpgsql_query_string = NULL;
+PLpgSQL_plugin  plugin_funcs = {
+       NULL,
+       NULL,
+       NULL,
+       pg_hint_plan_plpgsql_stmt_beg,
+       pg_hint_plan_plpgsql_stmt_end,
+       NULL,
+       NULL,
+};
+
+/* Current nesting depth of SPI calls, used to prevent recursive calls */
+static int     nested_level = 0;
+
 /*
  * 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.",
@@ -510,6 +563,17 @@ _PG_init(void)
                                                         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;
@@ -520,10 +584,9 @@ _PG_init(void)
        prev_join_search = join_search_hook;
        join_search_hook = pg_hint_plan_join_search;
 
-       /* PL/pgSQL plugin hook */
-       PLpgSQL_plugin  **var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
+       /* setup PL/pgSQL plugin hook */
+       var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
        *var_ptr = &plugin_funcs;
-       (&plugin_funcs)->func_setup = (void *)pg_hint_plan_plpgsql_func_setup;
 }
 
 /*
@@ -533,11 +596,17 @@ _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;
 }
 
 /*
@@ -698,6 +767,54 @@ 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)
 {
@@ -712,7 +829,6 @@ 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;
@@ -721,6 +837,7 @@ HintStateCreate(void)
        hstate->leading_hint = NULL;
        hstate->context = superuser() ? PGC_SUSET : PGC_USERSET;
        hstate->set_hints = NULL;
+       hstate->rows_hints = NULL;
 
        return hstate;
 }
@@ -885,8 +1002,28 @@ SetHintDesc(SetHint *hint, StringInfo buf)
        appendStringInfo(buf, ")\n");
 }
 
+static void
+RowsHintDesc(RowsHint *hint, StringInfo buf)
+{
+       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, ")\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
@@ -982,6 +1119,24 @@ 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);
@@ -1247,9 +1402,7 @@ 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)
                {
@@ -1336,21 +1489,88 @@ parse_hints(HintState *hstate, Query *parse, const char *str)
        pfree(buf.data);
 }
 
+
+/* 
+ * 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)
+{
+       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;
+
+       PG_TRY();
+       {
+               ++nested_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();
+       
+               --nested_level;
+       }
+       PG_CATCH();
+       {
+               --nested_level;
+               PG_RE_THROW();
+       }
+       PG_END_TRY();
+
+       return hints;
+}
+
 /*
- * Do basic parsing of the query head comment.
+ * Get client-supplied query string.
  */
-static HintState *
-parse_head_comment(Query *parse)
+static const char *
+get_query_string(void)
 {
        const char *p;
-       const char *hint_head;
-       char       *head;
-       char       *tail;
-       int                     len;
-       int                     i;
-       HintState   *hstate;
 
-       /* get client-supplied query string. */
        if (stmt_name)
        {
                PreparedStatement  *entry;
@@ -1358,8 +1578,24 @@ parse_head_comment(Query *parse)
                entry = FetchPreparedStatement(stmt_name, true);
                p = entry->plansource->query_string;
        }
+       else if (plpgsql_query_string)
+               p = plpgsql_query_string;
        else
-               p = hint_query_string;
+               p = debug_query_string;
+
+       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;
@@ -1418,8 +1654,25 @@ 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);
@@ -1444,7 +1697,7 @@ 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++)
@@ -1482,6 +1735,8 @@ parse_head_comment(Query *parse)
                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;
 }
@@ -1512,10 +1767,8 @@ 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)
                {
@@ -1570,7 +1823,6 @@ 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;
@@ -1581,7 +1833,6 @@ 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;
@@ -1777,6 +2028,97 @@ 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
  */
@@ -1791,13 +2133,8 @@ 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
        }
        PG_CATCH();
        {
@@ -1859,9 +2196,7 @@ 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
@@ -1871,9 +2206,7 @@ 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
@@ -1898,20 +2231,26 @@ 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 || nested_level > 0)
        {
                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;
        }
 
@@ -1945,7 +2284,7 @@ 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.
@@ -1966,17 +2305,19 @@ pg_hint_plan_ProcessUtility(Node *parsetree, const char *queryString,
                        stmt_name = estmt->name;
                }
        }
-#endif
+
        if (stmt_name)
        {
                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();
                {
@@ -1991,11 +2332,13 @@ 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);
 }
 
 /*
@@ -2035,28 +2378,73 @@ pop_hint(void)
 static PlannedStmt *
 pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 {
+       const char         *hints = NULL;
+       const char         *query;
+       char               *norm_query;
+       pgssJumbleState jstate;
+       int                             query_len;
        int                             save_nestlevel;
        PlannedStmt        *result;
        HintState          *hstate;
 
        /*
-        * 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)
-       {
-               current_hint = NULL;
+       if (!pg_hint_plan_enable_hint || nested_level > 0)
+               goto standard_planner_proc;
 
-               if (prev_planner)
-                       return (*prev_planner) (parse, cursorOptions, boundParams);
-               else
-                       return standard_planner(parse, cursorOptions, boundParams);
-       }
+       /* Create hint struct from client-supplied query string. */
+       query = get_query_string();
 
-       /* Create hint struct from parse tree. */
-       if (!hint_query_string)
-               hint_query_string = debug_query_string;
-       hstate = parse_head_comment(parse);
+       /*
+        * 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.
+        */
+       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);
+               elog(DEBUG1,
+                        "pg_hint_plan: get_hints_from_table [%s][%s]=>[%s]",
+                        norm_query, application_name, hints ? hints : "(none)");
+       }
+       if (hints == NULL)
+               hints = get_hints_from_comment(query);
+       hstate = create_hintstate(parse, hints);
 
        /*
         * Use standard planner if the statement has not valid hint.  Other hook
@@ -2064,14 +2452,7 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
         * NULL.
         */
        if (!hstate)
-       {
-               current_hint = NULL;
-
-               if (prev_planner)
-                       return (*prev_planner) (parse, cursorOptions, boundParams);
-               else
-                       return standard_planner(parse, cursorOptions, boundParams);
-       }
+               goto standard_planner_proc;
 
        /*
         * Push new hint struct to the hint stack to disable previous hint context.
@@ -2091,10 +2472,8 @@ 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)
@@ -2137,13 +2516,20 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
        pop_hint();
 
        return result;
+
+standard_planner_proc:
+       current_hint = NULL;
+       if (prev_planner)
+               return (*prev_planner) (parse, cursorOptions, boundParams);
+       else
+               return standard_planner(parse, cursorOptions, boundParams);
 }
 
 /*
  * 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;
@@ -2153,10 +2539,10 @@ 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)
@@ -2380,7 +2766,7 @@ 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))
                                        {
@@ -2389,7 +2775,7 @@ 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,
@@ -2498,7 +2884,7 @@ 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))
@@ -2518,7 +2904,7 @@ 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))
@@ -2546,104 +2932,134 @@ 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 || nested_level > 0)
                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)
+               return;
+
+       /* Find the parent for this relation */
+       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;
+                       break;
+               }
+       }
+
+       if (!l)
        {
-               /* store does relids of parent table. */
-               current_hint->parent_relid = rel->relid;
-               current_hint->parent_rel_oid = relationObjectId;
+               /* 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;
+
+               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);
 
-               /* append_rel_list contains all append rels; ignore others */
-               foreach(l, root->append_rel_list)
+               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);
                        }
                }
-
-               /* This rel is not inherit table. */
-               current_hint->parent_relid = 0;
-               current_hint->parent_rel_oid = InvalidOid;
-               current_hint->parent_hint = NULL;
+                       
+               set_scan_config_options(scanmask, current_hint->context);
        }
 
-       /*
-        * 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 (current_hint->parent_hint != 0)
        {
-               set_scan_config_options(current_hint->init_scan_mask,
-                                                               current_hint->context);
+               delete_indexes(current_hint->parent_hint, rel,
+                                          relationObjectId);
+
+               /* Scan fixation status is the same to the parent. */
                return;
        }
-       set_scan_config_options(hint->enforce_mask, current_hint->context);
-       hint->base.state = HINT_STATE_USED;
 
-       if (inhparent)
+       /* This table doesn't have a parent hint. Apply its own hint if any. */
+       if ((hint = find_scan_hint(root, rel->relid, rel)) != NULL)
        {
-               Relation    relation;
-               List       *indexoidlist;
-               ListCell   *l;
-
-               current_hint->parent_hint = hint;
-
-               relation = heap_open(relationObjectId, NoLock);
-               indexoidlist = RelationGetIndexList(relation);
-
-               foreach(l, indexoidlist)
-               {
-                       Oid         indexoid = lfirst_oid(l);
-                       char       *indexname = get_rel_name(indexoid);
-                       bool        use_index = false;
-                       ListCell   *lc;
-                       ParentIndexInfo *parent_index_info;
-
-                       foreach(lc, hint->indexnames)
-                       {
-                               if (RelnameCmp(&indexname, &lfirst(lc)) == 0)
-                               {
-                                       use_index = true;
-                                       break;
-                               }
-                       }
-                       if (!use_index)
-                               continue;
+               set_scan_config_options(hint->enforce_mask, current_hint->context);
+               hint->base.state = HINT_STATE_USED;
 
-                       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);
+               delete_indexes(hint, rel, InvalidOid);
        }
        else
-               delete_indexes(hint, rel, InvalidOid);
+               set_scan_config_options(current_hint->init_scan_mask,
+                                                               current_hint->context);
+       return;
 }
 
 /*
@@ -2800,6 +3216,46 @@ 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.
  *
@@ -2827,43 +3283,33 @@ 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];
-
-                       relid = find_relid_aliasname(root, relname, initial_rels,
-                                                                                hint->base.hint_str);
+               hint->joinrelids = create_bms_of_relids(&(hint->base), root,
+                                                                        initial_rels, hint->nrels, hint->relnames);
 
-                       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. */
@@ -2871,7 +3317,7 @@ 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++)
        {
@@ -3069,11 +3515,7 @@ 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);
@@ -3112,7 +3554,7 @@ 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
@@ -3198,7 +3640,7 @@ 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;
@@ -3279,9 +3721,10 @@ 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 || nested_level > 0)
        {
                if (prev_join_search)
                        return (*prev_join_search) (root, levels_needed, initial_rels);
@@ -3340,15 +3783,11 @@ 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);
@@ -3370,28 +3809,68 @@ set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
        }
 }
 
-static void
-pg_hint_plan_plpgsql_func_setup(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
-{
-       (&plugin_funcs)->stmt_beg = pg_hint_plan_plpgsql_stmt_beg;
-       (&plugin_funcs)->stmt_end = pg_hint_plan_plpgsql_stmt_end;
-}
-
+/*
+ * 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)
 {
-       if ((enum PLpgSQL_stmt_types) stmt->cmd_type == PLPGSQL_STMT_EXECSQL)
+       PLpgSQL_expr *expr = NULL;
+
+       switch ((enum PLpgSQL_stmt_types) stmt->cmd_type)
        {
-               PLpgSQL_expr *expr = ((PLpgSQL_stmt_execsql *) stmt)->sqlstmt;
-               hint_query_string = expr->query;
+               case PLPGSQL_STMT_FORS:
+                       expr = ((PLpgSQL_stmt_fors *) stmt)->query;
+                       break;
+               case PLPGSQL_STMT_FORC:
+                               expr = ((PLpgSQL_var *) (estate->datums[((PLpgSQL_stmt_forc *)stmt)->curvar]))->cursor_explicit_expr;
+                       break;
+               case PLPGSQL_STMT_RETURN_QUERY:
+                       if (((PLpgSQL_stmt_return_query *) stmt)->query != NULL)
+                               expr = ((PLpgSQL_stmt_return_query *) stmt)->query;
+                       else
+                               expr = ((PLpgSQL_stmt_return_query *) stmt)->dynquery;
+                       break;
+               case PLPGSQL_STMT_EXECSQL:
+                       expr = ((PLpgSQL_stmt_execsql *) stmt)->sqlstmt;
+                       break;
+               case PLPGSQL_STMT_DYNEXECUTE:
+                       expr = ((PLpgSQL_stmt_dynexecute *) stmt)->query;
+                       break;
+               case PLPGSQL_STMT_DYNFORS:
+                       expr = ((PLpgSQL_stmt_dynfors *) stmt)->query;
+                       break;
+               case PLPGSQL_STMT_OPEN:
+                       if (((PLpgSQL_stmt_open *) stmt)->query != NULL)
+                               expr = ((PLpgSQL_stmt_open *) stmt)->query;
+                       else if (((PLpgSQL_stmt_open *) stmt)->dynquery != NULL)
+                               expr = ((PLpgSQL_stmt_open *) stmt)->dynquery;
+                       else
+                               expr = ((PLpgSQL_var *) (estate->datums[((PLpgSQL_stmt_open *)stmt)->curvar]))->cursor_explicit_expr;
+                       break;
+               default:
+                       break;
        }
+
+       if (expr)
+               plpgsql_query_string = expr->query;
 }
 
+/*
+ * 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)
 {
        if ((enum PLpgSQL_stmt_types) stmt->cmd_type == PLPGSQL_STMT_EXECSQL)
-               hint_query_string = NULL;
+               plpgsql_query_string = NULL;
 }
 
 #define standard_join_search pg_hint_plan_standard_join_search
@@ -3403,3 +3882,5 @@ pg_hint_plan_plpgsql_stmt_end(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
 #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"