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pgsql: Allow WAL summarization to back up when timeline changes. 2+ messages / 1 participants [nested] [flat]
* pgsql: Allow WAL summarization to back up when timeline changes. @ 2024-07-26 14:09 Robert Haas <rhaas@postgresql.org> 0 siblings, 0 replies; 2+ messages in thread From: Robert Haas @ 2024-07-26 14:09 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Allow WAL summarization to back up when timeline changes. The old code believed that it was not possible to switch timelines without first replaying all of the WAL from the old timeline, but that turns out to be false, as demonstrated by an example from Fujii Masao. As a result, it assumed that summarization would always continue from the LSN where summarization previously ended. But in fact, when a timeline switch occurs without replaying all the WAL from the previous timeline, we can need to back up to an earlier LSN. Adjust accordingly. Discussion: https://postgr.es/m/CA+TgmoZGEsZodXC4f=XZNkAeyuDmWTSkpkjCEOcF19Am0mt_OA@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/cf8a4898360bbb70a0f9eec7bac8bcb4fcb7aa42 Modified Files -------------- src/backend/postmaster/walsummarizer.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) ^ permalink raw reply [nested|flat] 2+ messages in thread
* pgsql: Allow WAL summarization to back up when timeline changes. @ 2024-07-26 14:09 Robert Haas <rhaas@postgresql.org> 0 siblings, 0 replies; 2+ messages in thread From: Robert Haas @ 2024-07-26 14:09 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Allow WAL summarization to back up when timeline changes. The old code believed that it was not possible to switch timelines without first replaying all of the WAL from the old timeline, but that turns out to be false, as demonstrated by an example from Fujii Masao. As a result, it assumed that summarization would always continue from the LSN where summarization previously ended. But in fact, when a timeline switch occurs without replaying all the WAL from the previous timeline, we can need to back up to an earlier LSN. Adjust accordingly. Discussion: https://postgr.es/m/CA+TgmoZGEsZodXC4f=XZNkAeyuDmWTSkpkjCEOcF19Am0mt_OA@mail.gmail.com Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/c7cfbc5157fec24704ea102f113d97193ffe5f7f Modified Files -------------- src/backend/postmaster/walsummarizer.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2024-07-26 14:09 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2024-07-26 14:09 pgsql: Allow WAL summarization to back up when timeline changes. Robert Haas <rhaas@postgresql.org> 2024-07-26 14:09 pgsql: Allow WAL summarization to back up when timeline changes. Robert Haas <rhaas@postgresql.org>
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