On 2016/09/27 18:09, Ashutosh Bapat wrote:
>>> I tried to debug the problem somewhat. In set_append_rel_pathlist(),
>>> it finds that at least one child has a parameterized path as the
>>> cheapest path, so it doesn't create an unparameterized path for append
>>> rel. At the same time there is a parameterization common to all the
>>> children, so it doesn't create any path. There seem to be two problems
>>> here
>>> 1. The children from second level onwards may not be getting
>>> parameterized for lateral references. That seems unlikely but
>>> possible.
>
> Did you check this? We may be missing on creating index scan paths
> with parameterization. If we fix this, we don't need to
> re-parameterize Append.
You're right. How about the attached patch that fixes the problem along
these lines? The problem seems to be that multi-level inheritance sets
(partitioned tables) are not handled in create_lateral_join_info(), which
means that lateral_relids and lateral_referencers of the root relation are
not being propagated to the partitions below level 1.
I'm getting concerned about one thing though - for a given *regular*
inheritance set, the root->append_rel_list would be scanned only once; But
for a *partitioned table* inheritance set, it would be scanned for every
partitioned table in the set (ie, the root table and internal partitions).
Thanks,
Amit
commit d69aeabcfcb58f349602a1b7392c611045c37465
Author: amit <amitlangot...@gmail.com>
Date: Tue Sep 27 20:01:44 2016 +0900
Consider multi-level partitioned tables in create_lateral_join_info().
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 84ce6b3..74734f2 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -14,6 +14,7 @@
*/
#include "postgres.h"
+#include "catalog/pg_class.h"
#include "catalog/pg_type.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
@@ -623,8 +624,19 @@ create_lateral_join_info(PlannerInfo *root)
for (rti = 1; rti < root->simple_rel_array_size; rti++)
{
RelOptInfo *brel = root->simple_rel_array[rti];
+ RangeTblEntry *rte = root->simple_rte_array[rti];
- if (brel == NULL || brel->reloptkind != RELOPT_BASEREL)
+ if (brel == NULL)
+ continue;
+
+ /*
+ * If an "other rel" RTE is a "partitioned table", we must propagate
+ * the lateral info inherited from the parent to its children. That's
+ * because they are not linked directly with the parent via
+ * AppendRelInfo's (see expand_inherited_rte_internal()).
+ */
+ if (brel->reloptkind != RELOPT_BASEREL &&
+ rte->relkind != RELKIND_PARTITIONED_TABLE)
continue;
if (root->simple_rte_array[rti]->inh)
--
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