postgresql/src
Alexander Korotkov bedfdb85b0 Fix infinite wait when reading a partially written WAL record
If a crash occurs while writing a WAL record that spans multiple pages, the
recovery process marks the page with the XLP_FIRST_IS_OVERWRITE_CONTRECORD
flag.  However, logical decoding currently attempts to read the full WAL
record based on its expected size before checking this flag, which can lead
to an infinite wait if the remaining data is never written (e.g., no activity
after crash).

This patch updates the logic first to read the page header and check for
the XLP_FIRST_IS_OVERWRITE_CONTRECORD flag before attempting to reconstruct
the full WAL record.  If the flag is set, decoding correctly identifies
the record as incomplete and avoids waiting for WAL data that will never
arrive.

Discussion: https://postgr.es/m/CAAKRu_ZCOzQpEumLFgG_%2Biw3FTa%2BhJ4SRpxzaQBYxxM_ZAzWcA%40mail.gmail.com
Discussion: https://postgr.es/m/CALDaNm34m36PDHzsU_GdcNXU0gLTfFY5rzh9GSQv%3Dw6B%2BQVNRQ%40mail.gmail.com
Author: Vignesh C <vignesh21@gmail.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Backpatch-through: 13
2025-07-19 14:13:41 +03:00
..
backend Fix infinite wait when reading a partially written WAL record 2025-07-19 14:13:41 +03:00
bin Fix dumping of comments on invalid constraints on domains 2025-07-16 19:22:53 +02:00
common With GB18030, prevent SIGSEGV from reading past end of allocation. 2025-05-05 04:52:08 -07:00
fe_utils In fmtIdEnc(), handle failure of enlargePQExpBuffer(). 2025-02-16 12:46:35 -05:00
include Fix re-distributing previously distributed invalidation messages during logical decoding. 2025-06-16 17:35:50 -07:00
interfaces Fix PQport to never return NULL unless the connection is NULL. 2025-07-17 12:46:59 -04:00
makefiles Add NO_INSTALL option to pgxs 2021-05-27 13:58:29 +02:00
pl Restore the ability to run pl/pgsql expression queries in parallel. 2025-07-07 14:34:12 -04:00
port Make our usage of memset_s() conform strictly to the C11 standard. 2025-05-18 12:45:55 -04:00
template On NetBSD, force dynamic symbol resolution at postmaster start. 2022-08-30 17:29:03 -04:00
test Fix dumping of comments on invalid constraints on domains 2025-07-16 19:22:53 +02:00
timezone Update time zone data files to tzdata release 2025b. 2025-04-30 11:14:15 -04:00
tools Make our usage of memset_s() conform strictly to the C11 standard. 2025-05-18 12:45:55 -04:00
tutorial Doc: sync src/tutorial/basics.source with SGML documentation. 2022-11-19 13:09:14 -05:00
.gitignore
DEVELOPERS
Makefile Remove the option to build thread_test.c outside configure. 2020-10-21 12:08:48 -04:00
Makefile.global.in Suppress macOS warnings about duplicate libraries in link commands. 2023-09-29 14:07:30 -04:00
Makefile.shlib Stop using "-multiply_defined suppress" on macOS. 2023-09-26 21:06:21 -04:00
nls-global.mk Add errhint_plural() function and make use of it 2021-03-31 09:16:25 +02:00