* core.c
* Routines copied from PostgreSQL core distribution.
*
+
+ * The main purpose of this files is having access to static functions in core.
+ * Another purpose is tweaking functions behavior by replacing part of them by
+ * macro definitions. See at the end of pg_hint_plan.c for details. Anyway,
+ * this file *must* contain required functions without making any change.
+ *
+ * This file contains the following functions from corresponding files.
+ *
* src/backend/optimizer/path/allpaths.c
+ *
+ * static functions:
+ * set_plain_rel_pathlist()
+ * create_plain_partial_paths()
* set_append_rel_pathlist()
* generate_mergeappend_paths()
* get_cheapest_parameterized_child_path()
* accumulate_append_subpath()
- * standard_join_search()
+ *
+ * public functions:
+ * standard_join_search(): This funcion is not static. The reason for
+ * including this function is make_rels_by_clause_joins. In order to
+ * avoid generating apparently unwanted join combination, we decided to
+ * change the behavior of make_join_rel, which is called under this
+ * function.
*
* src/backend/optimizer/path/joinrels.c
- * join_search_one_level()
+ *
+ * public functions:
+ * join_search_one_level(): We have to modify this to call my definition of
+ * make_rels_by_clause_joins.
+ *
+ * static functions:
* make_rels_by_clause_joins()
* make_rels_by_clauseless_joins()
* join_is_legal()
* mark_dummy_rel()
* restriction_is_constant_false()
*
+ *
* Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*-------------------------------------------------------------------------
*/
+
+/*
+ * set_plain_rel_pathlist
+ * Build access paths for a plain relation (no subquery, no inheritance)
+ */
+static void
+set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+{
+ Relids required_outer;
+
+ /*
+ * We don't support pushing join clauses into the quals of a seqscan, but
+ * it could still have required parameterization due to LATERAL refs in
+ * its tlist.
+ */
+ required_outer = rel->lateral_relids;
+
+ /* Consider sequential scan */
+ add_path(rel, create_seqscan_path(root, rel, required_outer, 0));
+
+ /* If appropriate, consider parallel sequential scan */
+ if (rel->consider_parallel && required_outer == NULL)
+ create_plain_partial_paths(root, rel);
+
+ /* Consider index scans */
+ create_index_paths(root, rel);
+
+ /* Consider TID scans */
+ create_tidscan_paths(root, rel);
+}
+
+/*
+ * create_plain_partial_paths
+ * Build partial access paths for parallel scan of a plain relation
+ */
+static void
+create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel)
+{
+ int parallel_workers;
+
+ /*
+ * If the user has set the parallel_workers reloption, use that; otherwise
+ * select a default number of workers.
+ */
+ if (rel->rel_parallel_workers != -1)
+ parallel_workers = rel->rel_parallel_workers;
+ else
+ {
+ int parallel_threshold;
+
+ /*
+ * If this relation is too small to be worth a parallel scan, just
+ * return without doing anything ... unless it's an inheritance child.
+ * In that case, we want to generate a parallel path here anyway. It
+ * might not be worthwhile just for this relation, but when combined
+ * with all of its inheritance siblings it may well pay off.
+ */
+ if (rel->pages < (BlockNumber) min_parallel_relation_size &&
+ rel->reloptkind == RELOPT_BASEREL)
+ return;
+
+ /*
+ * Select the number of workers based on the log of the size of the
+ * relation. This probably needs to be a good deal more
+ * sophisticated, but we need something here for now. Note that the
+ * upper limit of the min_parallel_relation_size GUC is chosen to
+ * prevent overflow here.
+ */
+ parallel_workers = 1;
+ parallel_threshold = Max(min_parallel_relation_size, 1);
+ while (rel->pages >= (BlockNumber) (parallel_threshold * 3))
+ {
+ parallel_workers++;
+ parallel_threshold *= 3;
+ if (parallel_threshold > INT_MAX / 3)
+ break; /* avoid overflow */
+ }
+ }
+
+ /*
+ * In no case use more than max_parallel_workers_per_gather workers.
+ */
+ parallel_workers = Min(parallel_workers, max_parallel_workers_per_gather);
+
+ /* If any limit was set to zero, the user doesn't want a parallel scan. */
+ if (parallel_workers <= 0)
+ return;
+
+ /* Add an unordered partial path based on a parallel sequential scan. */
+ add_partial_path(rel, create_seqscan_path(root, rel, NULL, parallel_workers));
+}
+
/*
* set_append_rel_pathlist
* Build access paths for an "append relation"
}
/*
- * restriction_is_constant_false --- is a restrictlist just FALSE?
+ * restriction_is_constant_false --- is a restrictlist just false?
*
- * In cases where a qual is provably constant FALSE, eval_const_expressions
+ * In cases where a qual is provably constant false, eval_const_expressions
* will generally have thrown away anything that's ANDed with it. In outer
* join situations this will leave us computing cartesian products only to
* decide there's no match for an outer row, which is pretty stupid. So,
* we need to detect the case.
*
- * If only_pushed_down is TRUE, then consider only pushed-down quals.
+ * If only_pushed_down is true, then consider only quals that are pushed-down
+ * from the point of view of the joinrel.
*/
static bool
-restriction_is_constant_false(List *restrictlist, bool only_pushed_down)
+restriction_is_constant_false(List *restrictlist,
+ RelOptInfo *joinrel,
+ bool only_pushed_down)
{
ListCell *lc;
RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
Assert(IsA(rinfo, RestrictInfo));
- if (only_pushed_down && !rinfo->is_pushed_down)
+ if (only_pushed_down && !RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
continue;
if (rinfo->clause && IsA(rinfo->clause, Const))
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