database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-25 12:03:53 +03:00
Code Activity

Fix regression in parallel planning against inheritance tables.

Browse Source 
Commit 51ee6f3160 accidentally changed
the behavior around inheritance hierarchies; before, we always
considered parallel paths even for very small inheritance children,
because otherwise an inheritance hierarchy with even one small child
wouldn't be eligible for parallelism.  That exception was inadverently
removed; put it back.

In passing, also adjust the degree-of-parallelism comptuation for
index-only scans not to consider the number of heap pages fetched.
Otherwise, we'll avoid parallel index-only scans on tables that are
mostly all-visible, which isn't especially logical.

Robert Haas and Amit Kapila, per a report from Ashutosh Sharma.

Discussion: http://postgr.es/m/CAE9k0PmgSoOHRd60SHu09aRVTHRSs8s6pmyhJKWHxWw9C_x+XA@mail.gmail.com
This commit is contained in:
Robert Haas
2017-03-14 14:33:14 -04:00
parent c11453ce0a
commit 2609e91fcf
3 changed files with 36 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
src/include/optimizer/paths.h
View File

@@ -54,8 +54,8 @@ extern RelOptInfo *standard_join_search(PlannerInfo *root, int levels_needed,
List *initial_rels);
extern void generate_gather_paths(PlannerInfo *root, RelOptInfo *rel);
extern int compute_parallel_worker(RelOptInfo *rel, BlockNumber heap_pages,
BlockNumber index_pages);
extern int compute_parallel_worker(RelOptInfo *rel, double heap_pages,
double index_pages);
extern void create_partial_bitmap_paths(PlannerInfo *root, RelOptInfo *rel,
Path *bitmapqual);