| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | pgsql-committers(at)lists(dot)postgresql(dot)org |
| Subject: | pgsql: ANALYZE a_star and its children to avoid plan instability in tes |
| Date: | 2019-09-27 15:28:33 |
| Message-ID: | E1iDsAb-0004mT-WD@gemulon.postgresql.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-committers |
ANALYZE a_star and its children to avoid plan instability in tests.
We've noted certain EXPLAIN queries on these tables occasionally showing
unexpected plan choices. This seems to happen because VACUUM sometimes
fails to update relpages/reltuples for one of these single-page tables,
due to bgwriter or checkpointer holding a pin on the lone page at just
the wrong time. To ensure those values get set, insert explicit ANALYZE
operations on these tables after we finish populating them. This
doesn't seem to affect any other test cases, so it's a usable fix.
Back-patch to v12. In principle the issue exists further back, but
we have not seen it before v12, so I won't risk back-patching further.
Discussion: https://postgr.es/m/24480.1569518042@sss.pgh.pa.us
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/b9bffa004a9980ac235b6ff541ee2fe0e9800372
Modified Files
--------------
src/test/regress/expected/create_misc.out | 7 +++++++
src/test/regress/sql/create_misc.sql | 8 ++++++++
2 files changed, 15 insertions(+)
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2019-09-27 15:28:34 | pgsql: ANALYZE a_star and its children to avoid plan instability in tes |
| Previous Message | Tom Lane | 2019-09-27 15:02:06 | pgsql: Doc: clean up markup for jsonb_set and related functions. |