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[pghintplan/pg_hint_plan.git] / make_join_rel.c
index c058246..638e500 100644 (file)
@@ -1,18 +1,56 @@
 /*-------------------------------------------------------------------------
  *
  * make_join_rel.c
- *       Routines copied from PostgreSQL core distribution.
+ *       Routines copied from PostgreSQL core distribution with some
+ *       modifications.
  *
  * src/backend/optimizer/path/joinrels.c
+ *
+ * This file contains the following functions from corresponding files.
+ *
+ *     static functions:
  *     make_join_rel()
+ *     populate_joinrel_with_paths()
  *
- * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
+ * Portions Copyright (c) 2013-2020, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *-------------------------------------------------------------------------
  */
 
 /*
+ * adjust_rows: tweak estimated row numbers according to the hint.
+ */
+static double
+adjust_rows(double rows, RowsHint *hint)
+{
+       double          result = 0.0;   /* keep compiler quiet */
+
+       if (hint->value_type == RVT_ABSOLUTE)
+               result = hint->rows;
+       else if (hint->value_type == RVT_ADD)
+               result = rows + hint->rows;
+       else if (hint->value_type == RVT_SUB)
+               result =  rows - hint->rows;
+       else if (hint->value_type == RVT_MULTI)
+               result = rows * hint->rows;
+       else
+               Assert(false);  /* unrecognized rows value type */
+
+       hint->base.state = HINT_STATE_USED;
+       if (result < 1.0)
+               ereport(WARNING,
+                               (errmsg("Force estimate to be at least one row, to avoid possible divide-by-zero when interpolating costs : %s",
+                                       hint->base.hint_str)));
+       result = clamp_row_est(result);
+       elog(DEBUG1, "adjusted rows %d to %d", (int) rows, (int) result);
+
+       return result;
+}
+
+
+/*
  * make_join_rel
  *        Find or create a join RelOptInfo that represents the join of
  *        the two given rels, and add to it path information for paths
@@ -60,7 +98,7 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
 
        /*
         * If it's a plain inner join, then we won't have found anything in
-        * join_info_list.      Make up a SpecialJoinInfo so that selectivity
+        * join_info_list.  Make up a SpecialJoinInfo so that selectivity
         * estimation functions will know what's being joined.
         */
        if (sjinfo == NULL)
@@ -75,7 +113,10 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
                /* we don't bother trying to make the remaining fields valid */
                sjinfo->lhs_strict = false;
                sjinfo->delay_upper_joins = false;
-               sjinfo->join_quals = NIL;
+               sjinfo->semi_can_btree = false;
+               sjinfo->semi_can_hash = false;
+               sjinfo->semi_operators = NIL;
+               sjinfo->semi_rhs_exprs = NIL;
        }
 
        /*
@@ -85,6 +126,84 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
        joinrel = build_join_rel(root, joinrelids, rel1, rel2, sjinfo,
                                                         &restrictlist);
 
+       /* !!! START: HERE IS THE PART WHICH IS ADDED FOR PG_HINT_PLAN !!! */
+       {
+               RowsHint   *rows_hint = NULL;
+               int                     i;
+               RowsHint   *justforme = NULL;
+               RowsHint   *domultiply = NULL;
+
+               /* Search for applicable rows hint for this join node */
+               for (i = 0; i < current_hint_state->num_hints[HINT_TYPE_ROWS]; i++)
+               {
+                       rows_hint = current_hint_state->rows_hints[i];
+
+                       /*
+                        * Skip this rows_hint if it is invalid from the first or it
+                        * doesn't target any join rels.
+                        */
+                       if (!rows_hint->joinrelids ||
+                               rows_hint->base.state == HINT_STATE_ERROR)
+                               continue;
+
+                       if (bms_equal(joinrelids, rows_hint->joinrelids))
+                       {
+                               /*
+                                * This joinrel is just the target of this rows_hint, so tweak
+                                * rows estimation according to the hint.
+                                */
+                               justforme = rows_hint;
+                       }
+                       else if (!(bms_is_subset(rows_hint->joinrelids, rel1->relids) ||
+                                          bms_is_subset(rows_hint->joinrelids, rel2->relids)) &&
+                                        bms_is_subset(rows_hint->joinrelids, joinrelids) &&
+                                        rows_hint->value_type == RVT_MULTI)
+                       {
+                               /*
+                                * If the rows_hint's target relids is not a subset of both of
+                                * component rels and is a subset of this joinrel, ths hint's
+                                * targets spread over both component rels. This menas that
+                                * this hint has been never applied so far and this joinrel is
+                                * the first (and only) chance to fire in current join tree.
+                                * Only the multiplication hint has the cumulative nature so we
+                                * apply only RVT_MULTI in this way.
+                                */
+                               domultiply = rows_hint;
+                       }
+               }
+
+               if (justforme)
+               {
+                       /*
+                        * If a hint just for me is found, no other adjust method is
+                        * useles, but this cannot be more than twice becuase this joinrel
+                        * is already adjusted by this hint.
+                        */
+                       if (justforme->base.state == HINT_STATE_NOTUSED)
+                               joinrel->rows = adjust_rows(joinrel->rows, justforme);
+               }
+               else
+               {
+                       if (domultiply)
+                       {
+                               /*
+                                * If we have multiple routes up to this joinrel which are not
+                                * applicable this hint, this multiply hint will applied more
+                                * than twice. But there's no means to know of that,
+                                * re-estimate the row number of this joinrel always just
+                                * before applying the hint. This is a bit different from
+                                * normal planner behavior but it doesn't harm so much.
+                                */
+                               set_joinrel_size_estimates(root, joinrel, rel1, rel2, sjinfo,
+                                                                                  restrictlist);
+                               
+                               joinrel->rows = adjust_rows(joinrel->rows, domultiply);
+                       }
+                       
+               }
+       }
+       /* !!! END: HERE IS THE PART WHICH IS ADDED FOR PG_HINT_PLAN !!! */
+
        /*
         * If we've already proven this join is empty, we needn't consider any
         * more paths for it.
@@ -95,6 +214,28 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
                return joinrel;
        }
 
+       /* Add paths to the join relation. */
+       populate_joinrel_with_paths(root, rel1, rel2, joinrel, sjinfo,
+                                                               restrictlist);
+
+       bms_free(joinrelids);
+
+       return joinrel;
+}
+
+
+/*
+ * populate_joinrel_with_paths
+ *       Add paths to the given joinrel for given pair of joining relations. The
+ *       SpecialJoinInfo provides details about the join and the restrictlist
+ *       contains the join clauses and the other clauses applicable for given pair
+ *       of the joining relations.
+ */
+static void
+populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
+                                                       RelOptInfo *rel2, RelOptInfo *joinrel,
+                                                       SpecialJoinInfo *sjinfo, List *restrictlist)
+{
        /*
         * Consider paths using each rel as both outer and inner.  Depending on
         * the join type, a provably empty outer or inner rel might mean the join
@@ -117,7 +258,7 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
        {
                case JOIN_INNER:
                        if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
-                               restriction_is_constant_false(restrictlist, false))
+                               restriction_is_constant_false(restrictlist, joinrel, false))
                        {
                                mark_dummy_rel(joinrel);
                                break;
@@ -131,12 +272,12 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
                        break;
                case JOIN_LEFT:
                        if (is_dummy_rel(rel1) ||
-                               restriction_is_constant_false(restrictlist, true))
+                               restriction_is_constant_false(restrictlist, joinrel, true))
                        {
                                mark_dummy_rel(joinrel);
                                break;
                        }
-                       if (restriction_is_constant_false(restrictlist, false) &&
+                       if (restriction_is_constant_false(restrictlist, joinrel, false) &&
                                bms_is_subset(rel2->relids, sjinfo->syn_righthand))
                                mark_dummy_rel(rel2);
                        add_paths_to_joinrel(root, joinrel, rel1, rel2,
@@ -148,7 +289,7 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
                        break;
                case JOIN_FULL:
                        if ((is_dummy_rel(rel1) && is_dummy_rel(rel2)) ||
-                               restriction_is_constant_false(restrictlist, true))
+                               restriction_is_constant_false(restrictlist, joinrel, true))
                        {
                                mark_dummy_rel(joinrel);
                                break;
@@ -184,7 +325,7 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
                                bms_is_subset(sjinfo->min_righthand, rel2->relids))
                        {
                                if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
-                                       restriction_is_constant_false(restrictlist, false))
+                                       restriction_is_constant_false(restrictlist, joinrel, false))
                                {
                                        mark_dummy_rel(joinrel);
                                        break;
@@ -207,7 +348,7 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
                                                                   sjinfo) != NULL)
                        {
                                if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
-                                       restriction_is_constant_false(restrictlist, false))
+                                       restriction_is_constant_false(restrictlist, joinrel, false))
                                {
                                        mark_dummy_rel(joinrel);
                                        break;
@@ -222,12 +363,12 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
                        break;
                case JOIN_ANTI:
                        if (is_dummy_rel(rel1) ||
-                               restriction_is_constant_false(restrictlist, true))
+                               restriction_is_constant_false(restrictlist, joinrel, true))
                        {
                                mark_dummy_rel(joinrel);
                                break;
                        }
-                       if (restriction_is_constant_false(restrictlist, false) &&
+                       if (restriction_is_constant_false(restrictlist, joinrel, false) &&
                                bms_is_subset(rel2->relids, sjinfo->syn_righthand))
                                mark_dummy_rel(rel2);
                        add_paths_to_joinrel(root, joinrel, rel1, rel2,
@@ -240,7 +381,6 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
                        break;
        }
 
-       bms_free(joinrelids);
-
-       return joinrel;
+       /* Apply partitionwise join technique, if possible. */
+       try_partitionwise_join(root, rel1, rel2, joinrel, sjinfo, restrictlist);
 }