From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | pgsql-committers(at)lists(dot)postgresql(dot)org |
Subject: | pgsql: Ensure we have a snapshot while dropping ON COMMIT DROP temp tab |
Date: | 2023-10-16 18:06:46 |
Message-ID: | E1qsRzK-000sVo-Fb@gemulon.postgresql.org |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-committers |
Ensure we have a snapshot while dropping ON COMMIT DROP temp tables.
Dropping a temp table could entail TOAST table access to clean out
toasted catalog entries, such as large pg_constraint.conbin strings
for complex CHECK constraints. If we did that via ON COMMIT DROP,
we triggered the assertion in init_toast_snapshot(), because
there was no provision for setting up a snapshot for the drop
actions. Fix that.
(I assume here that the adjacent truncation actions for ON COMMIT
DELETE ROWS don't have a similar problem: it doesn't seem like
nontransactional truncations would need to touch any toasted fields.
If that proves wrong, we could refactor a bit to have the same
snapshot acquisition cover that too.)
The test case added here does not fail before v15, because that
assertion was added in 277692220 which was not back-patched.
However, the race condition the assertion warns of surely
exists further back, so back-patch to all supported branches.
Per report from Richard Guo.
Discussion: https://postgr.es/m/CAMbWs4-x26=_QxxgdJyNbiCDzvtr2WV5ZDso_v-CukKEe6cBZw@mail.gmail.com
Branch
------
REL_13_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/1e678175c575ea4af1d39cff0d8abceb3c1ae8a5
Modified Files
--------------
src/backend/commands/tablecmds.c | 8 ++++++++
src/test/regress/expected/temp.out | 20 ++++++++++++++++++++
src/test/regress/sql/temp.sql | 16 ++++++++++++++++
3 files changed, 44 insertions(+)
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2023-10-16 19:45:09 | pgsql: Add regression test coverage for timetz_izone(). |
Previous Message | Nathan Bossart | 2023-10-16 17:45:06 | pgsql: Move extra code out of the Pre/PostRestoreCommand() section. |