Fix wrong result in parallel ChunkAppend - #9388
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Some fields were not initialized properly in case when there's no startup exclusion but runtime parent exclusion, which led us to excluding the chunks that actually match. Refactor the way we work with the lists of the matched plans to prevent confusion. Now we use the same initial list of matched plans always, and keep a separate list of plan states (excluded/finished/etc) which is used for iteration.
The test for parallel ChunkAppend with InitPlan params filtered on column i (the partitioning column). This caused the planner to set runtime_exclusion_children, which made it pick a Single Copy Gather plan instead of a parallel-aware ChunkAppend. The shared-memory subplan coordination path was never exercised, so the test passed even with the buggy code. Switch the filter to column j (non-partitioning column) so the planner produces a truly parallel ChunkAppend with only runtime_exclusion_parent. This correctly exposes the bug where parallel workers received empty subplan lists from shared memory. Verified on PG17 and PG18: - Old code + new test: workers_ok = f (bug detected) - Fixed code + new test: workers_ok = t (bug fixed)
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The partial and non-partial plan tests only ran EXPLAIN without executing the query, so the worker code path that marks non-partial plans as finished was never covered. Add actual query execution to exercise that path.
Cover the do_runtime_exclusion code path where ts_chunk_append_get_scan_plan returns NULL for a MergeAppend child in an ordered ChunkAppend with space partitioning. This exercises the continue at exec.c:456 (scan == NULL skip). The test creates a space-partitioned hypertable where one time slice has data in both space partitions (producing a MergeAppend child) and another has data in only one partition (producing a direct scan child). A LATERAL join triggers runtime chunk exclusion, which must handle both child types.
Shared tests run in parallel in the same database and must not create new tables. Move to tsl/test/sql/ where each test gets its own database.
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LIMIT 3 with the previous data sizes produced half-integer per-loop
averages (e.g. 5 result rows over 2 LATERAL loops yielded 2.5). PG
versions disagree on how to format these: pre-PG18 rounds to integer
("2.00"), PG18 prints "2.50". Increase the data so all per-loop
averages are integers (LIMIT 4, 4 rows in slice 1, 4 rows in slice 2).
Also drop the spurious blank line in parallel-15.out and parallel-16.out
that was introduced during the merge with main.
akuzm
commented
May 20, 2026
| -- This file and its contents are licensed under the Timescale License. | ||
| -- Please see the included NOTICE for copyright information and | ||
| -- LICENSE-TIMESCALE for a copy of the license. | ||
| -- Test runtime chunk exclusion in an ordered ChunkAppend with space |
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This test is just for improving coverage, it doesn't trigger any bug, that's why it's passing on main too.
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Some fields were not initialized properly in case when there's no startup exclusion but runtime parent exclusion, which led us to excluding the chunks that actually match.
Refactor the way we work with the lists of the matched plans to prevent confusion. Now we use the same initial list of matched plans always, and keep a separate list of plan states (excluded/finished/etc) which is used for iteration.
Parts: