Assorted preparatory refactoring for partition-wise join.

Instead of duplicating the logic to search for a matching
ParamPathInfo in multiple places, factor it out into a separate
function.

Pass only the relevant bits of the PartitionKey to
partition_bounds_equal instead of the whole thing, because
partition-wise join will want to call this without having a
PartitionKey available.

Adjust allow_star_schema_join and calc_nestloop_required_outer
to take relevant Relids rather than the entire Path, because
partition-wise join will want to call it with the top-parent
relids to determine whether a child join is allowable.

Ashutosh Bapat.  Review and testing of the larger patch set of which
this is a part by Amit Langote, Rajkumar Raghuwanshi, Rafia Sabih,
Thomas Munro, Dilip Kumar, and me.

Discussion: http://postgr.es/m/CA+TgmobQK80vtXjAsPZWWXd7c8u13G86gmuLupN+uUJjA+i4nA@mail.gmail.com

1 files changed, 26 insertions, 19 deletions

diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index c8e2b67da42..8ad0b4a6697 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -1048,12 +1048,8 @@ get_baserel_parampathinfo(PlannerInfo *root, RelOptInfo *baserel,
 	Assert(!bms_overlap(baserel->relids, required_outer));
 
 	/* If we already have a PPI for this parameterization, just return it */
-	foreach(lc, baserel->ppilist)
-	{
-		ppi = (ParamPathInfo *) lfirst(lc);
-		if (bms_equal(ppi->ppi_req_outer, required_outer))
-			return ppi;
-	}
+	if ((ppi = find_param_path_info(baserel, required_outer)))
+		return ppi;
 
 	/*
 	 * Identify all joinclauses that are movable to this base rel given this
@@ -1290,12 +1286,8 @@ get_joinrel_parampathinfo(PlannerInfo *root, RelOptInfo *joinrel,
 	*restrict_clauses = list_concat(pclauses, *restrict_clauses);
 
 	/* If we already have a PPI for this parameterization, just return it */
-	foreach(lc, joinrel->ppilist)
-	{
-		ppi = (ParamPathInfo *) lfirst(lc);
-		if (bms_equal(ppi->ppi_req_outer, required_outer))
-			return ppi;
-	}
+	if ((ppi = find_param_path_info(joinrel, required_outer)))
+		return ppi;
 
 	/* Estimate the number of rows returned by the parameterized join */
 	rows = get_parameterized_joinrel_size(root, joinrel,
@@ -1334,7 +1326,6 @@ ParamPathInfo *
 get_appendrel_parampathinfo(RelOptInfo *appendrel, Relids required_outer)
 {
 	ParamPathInfo *ppi;
-	ListCell   *lc;
 
 	/* Unparameterized paths have no ParamPathInfo */
 	if (bms_is_empty(required_outer))
@@ -1343,12 +1334,8 @@ get_appendrel_parampathinfo(RelOptInfo *appendrel, Relids required_outer)
 	Assert(!bms_overlap(appendrel->relids, required_outer));
 
 	/* If we already have a PPI for this parameterization, just return it */
-	foreach(lc, appendrel->ppilist)
-	{
-		ppi = (ParamPathInfo *) lfirst(lc);
-		if (bms_equal(ppi->ppi_req_outer, required_outer))
-			return ppi;
-	}
+	if ((ppi = find_param_path_info(appendrel, required_outer)))
+		return ppi;
 
 	/* Else build the ParamPathInfo */
 	ppi = makeNode(ParamPathInfo);
@@ -1359,3 +1346,23 @@ get_appendrel_parampathinfo(RelOptInfo *appendrel, Relids required_outer)
 
 	return ppi;
 }
+
+/*
+ * Returns a ParamPathInfo for the parameterization given by required_outer, if
+ * already available in the given rel. Returns NULL otherwise.
+ */
+ParamPathInfo *
+find_param_path_info(RelOptInfo *rel, Relids required_outer)
+{
+	ListCell   *lc;
+
+	foreach(lc, rel->ppilist)
+	{
+		ParamPathInfo *ppi = (ParamPathInfo *) lfirst(lc);
+
+		if (bms_equal(ppi->ppi_req_outer, required_outer))
+			return ppi;
+	}
+
+	return NULL;
+}