* src/backend/optimizer/path/allpaths.c
*
* static functions:
- * set_plain_rel_pathlist()
+ * set_plain_rel_pathlist()
+ * create_plain_partial_paths()
* set_append_rel_pathlist()
* generate_mergeappend_paths()
* get_cheapest_parameterized_child_path()
* restriction_is_constant_false()
*
*
- * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*-------------------------------------------------------------------------
}
/*
+ * 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"
*/
}
/*
- * 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;
-
- parallel_workers = compute_parallel_worker(rel, rel->pages);
-
- /* 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));
-}
-
-/*
- * Compute the number of parallel workers that should be used to scan a
- * relation. "pages" is the number of pages from the relation that we
- * expect to scan.
- */
-static int
-compute_parallel_worker(RelOptInfo *rel, BlockNumber pages)
-{
- 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 (pages < (BlockNumber) min_parallel_relation_size &&
- rel->reloptkind == RELOPT_BASEREL)
- return 0;
-
- /*
- * 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 (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);
-
- return parallel_workers;
-}
-
-
-/*
* join_search_one_level
* Consider ways to produce join relations containing exactly 'level'
* jointree items. (This is one step of the dynamic-programming method
}
/*
- * 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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