From: Noah Misch <noah@leadboat.com>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Consistently test for in-use shared memory.
Date: Thu, 04 Apr 2019 00:16:55 +0000
Message-ID: <E1hBq3r-0002EL-Cj@gemulon.postgresql.org> (raw)
Consistently test for in-use shared memory.
postmaster startup scrutinizes any shared memory segment recorded in
postmaster.pid, exiting if that segment matches the current data
directory and has an attached process. When the postmaster.pid file was
missing, a starting postmaster used weaker checks. Change to use the
same checks in both scenarios. This increases the chance of a startup
failure, in lieu of data corruption, if the DBA does "kill -9 `head -n1
postmaster.pid` && rm postmaster.pid && pg_ctl -w start". A postmaster
will no longer recycle segments pertaining to other data directories.
That's good for production, but it's bad for integration tests that
crash a postmaster and immediately delete its data directory. Such a
test now leaks a segment indefinitely. No "make check-world" test does
that. win32_shmem.c already avoided all these problems. In 9.6 and
later, enhance PostgresNode to facilitate testing. Back-patch to 9.4
(all supported versions).
Reviewed by Daniel Gustafsson and Kyotaro HORIGUCHI.
Discussion: https://postgr.es/m/20130911033341.GD225735@tornado.leadboat.com
Branch
------
REL9_4_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/3a70b66e625707bf3f8856be2a3d0ea74d6170d7
Modified Files
--------------
src/backend/port/sysv_shmem.c | 255 ++++++++++++++++++++----------------
src/backend/port/win32_shmem.c | 7 +-
src/backend/postmaster/postmaster.c | 12 +-
src/backend/storage/ipc/ipci.c | 14 +-
src/backend/utils/init/postinit.c | 6 +-
src/include/storage/ipc.h | 2 +-
src/include/storage/pg_shmem.h | 6 +-
7 files changed, 164 insertions(+), 138 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: noah@leadboat.com, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Consistently test for in-use shared memory.
In-Reply-To: <E1hBq3r-0002EL-Cj@gemulon.postgresql.org>
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