pgsql: Fix lock assertions in dshash.c. - Mailing list pgsql-committers

From Thomas Munro
Subject pgsql: Fix lock assertions in dshash.c.
Date
Msg-id E1oAlJk-002Dj2-Lc@gemulon.postgresql.org
Whole thread Raw
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Fix lock assertions in dshash.c.

dshash.c previously maintained flags to be able to assert that you
didn't hold any partition lock.  These flags could get out of sync with
reality in error scenarios.

Get rid of all that, and make assertions about the locks themselves
instead.  Since LWLockHeldByMe() loops internally, we don't want to put
that inside another loop over all partition locks.  Introduce a new
debugging-only interface LWLockAnyHeldByMe() to avoid that.

This problem was noted by Tom and Andres while reviewing changes to
support the new shared memory stats system, and later showed up in
reality while working on commit 389869af.

Back-patch to 11, where dshash.c arrived.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Reported-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220311012712.botrpsikaufzteyt@alap3.anarazel.de
Discussion: https://postgr.es/m/CA%2BhUKGJ31Wce6HJ7xnVTKWjFUWQZPBngxfJVx4q0E98pDr3kAw%40mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/eed959a457ea0ffb042f4881e23358ba145d148c

Modified Files
--------------
src/backend/lib/dshash.c          | 44 +++++++++------------------------------
src/backend/storage/lmgr/lwlock.c | 26 +++++++++++++++++++++++
src/include/storage/lwlock.h      |  1 +
3 files changed, 37 insertions(+), 34 deletions(-)


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