Thread: pgsql: Allow special SKIP LOCKED condition in Assert()

pgsql: Allow special SKIP LOCKED condition in Assert()

From
Alvaro Herrera
Date:
Allow special SKIP LOCKED condition in Assert()

Under concurrency, it is possible for two sessions to be merrily locking
and releasing a tuple and marking it again as HEAP_XMAX_INVALID all the
while a third session attempts to lock it, miserably fails at it, and
then contemplates life, the universe and everything only to eventually
fail an assertion that said bit is not set.  Before SKIP LOCKED that was
indeed a reasonable expectation, but alas! commit df630b0dd5ea falsified
it.

This bug is as old as time itself, and even older, if you think time
begins with the oldest supported branch.  Therefore, backpatch to all
supported branches.

Author: Simon Riggs <simon.riggs@enterprisedb.com>
Discussion: https://postgr.es/m/CANbhV-FeEwMnN8yuMyss7if1ZKjOKfjcgqB26n8pqu1e=q0ebg@mail.gmail.com

Branch
------
REL_11_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/28cd57416eb7cb6642eb23bd8acbf2f41ce76844

Modified Files
--------------
src/backend/access/heap/heapam.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)