database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-11 20:28:21 +03:00
Code Activity

Revert commit 66c0185a3 and follow-on patches.

Browse Source 
This reverts 66c0185a3 (Allow planner to use Merge Append to
efficiently implement UNION) as well as the follow-on commits
d5d2205c8, 3b1a7eb28, 7487044d6.  In addition to those, 07746a8ef
had to be removed then re-applied in a different place, because
66c0185a3 moved the relevant code.

The reason for this last-minute thrashing is that depesz found a
case in which the patched code creates a completely wrong plan
that silently gives incorrect query results.  It's unclear what
the cause is or how many cases are affected, but with beta1 wrap
staring us in the face, there's no time for closer investigation.
After we figure that out, we can decide whether to un-revert this
for beta2 or hold it for v18.

Discussion: https://postgr.es/m/Zktzf926vslR35Fv@depesz.com
(also some private discussion among pgsql-release)
This commit is contained in:
Tom Lane
2024-05-20 15:08:30 -04:00
parent d2a04470aa
commit 7204f35919
18 changed files with 287 additions and 761 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
contrib/postgres_fdw/sql/postgres_fdw.sql
View File

@ -3885,11 +3885,6 @@ DROP INDEX base_tbl2_idx;
DROP INDEX async_p3_idx;
-- UNION queries
SET enable_sort TO off;
SET enable_incremental_sort TO off;
-- Adjust fdw_startup_cost so that we get an unordered path in the Append.
ALTER SERVER loopback2 OPTIONS (ADD fdw_startup_cost '0.00');
EXPLAIN (VERBOSE, COSTS OFF)
INSERT INTO result_tbl
(SELECT a, b, 'AAA' || c FROM async_p1 ORDER BY a LIMIT 10)
@ -3916,10 +3911,6 @@ UNION ALL
SELECT * FROM result_tbl ORDER BY a;
DELETE FROM result_tbl;
RESET enable_incremental_sort;
RESET enable_sort;
ALTER SERVER loopback2 OPTIONS (DROP fdw_startup_cost);
-- Disable async execution if we use gating Result nodes for pseudoconstant
-- quals
EXPLAIN (VERBOSE, COSTS OFF)