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pgsql: Rework pgstat_write_statsfile() in combination with to_serialize 2+ messages / 1 participants [nested] [flat]
* pgsql: Rework pgstat_write_statsfile() in combination with to_serialize @ 2026-07-15 01:53 Michael Paquier <michael@paquier.xyz> 0 siblings, 0 replies; 2+ messages in thread From: Michael Paquier @ 2026-07-15 01:53 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Rework pgstat_write_statsfile() in combination with to_serialized_data Contrary to the from_serialized_data callback used by the pgstats reads at startup, the to_serialized_data callback used for the pgstats writes matched with pgstat_write_statsfile(), by not returning a boolean status, expecting a ferror() failure to deal with the discard of the stats file should an error happen while writing the stats. This was slightly confusing designed this way. Things are changed in this commit with: - to_serialized_data now returns a boolean status on a write failure. pgstat_write_statsfile() detects that and switches to failure mode instead of continuing to process the entries to write, speeding up the shutdown. - pgstat_write_statsfile() now uses STATS_DISCARD if a failure happens, to let the registered callbacks directly know that something is wrong, and that things need to be cleaned up. This gives a better error path detection for custom stats kinds. For example, they do not have to rely solely on the expectation of an ferror() for an auxiliary file. This new set of behaviors matches with what is already done in pgstat_read_statsfile() for the finish() callback (DISCARD on failure, READ on success) and the from_serialized_data with a status returned. Author: Sami Imseih <samimseih@gmail.com> Discussion: https://postgr.es/m/CAA5RZ0sMgOvuhpb2P=KSJOjgjC6AfUu+GYcu9mHar-y_Xtd=Pg@mail.gmail.com Backpatch-through: 19 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/572c3b2ddf8c90303d57bf33add4dcbf1b30b866 Modified Files -------------- src/backend/utils/activity/pgstat.c | 34 ++++++++++++++++++---- src/include/utils/pgstat_internal.h | 5 ++-- .../test_custom_stats/test_custom_var_stats.c | 29 +++++++++++------- 3 files changed, 49 insertions(+), 19 deletions(-) ^ permalink raw reply [nested|flat] 2+ messages in thread
* pgsql: Rework pgstat_write_statsfile() in combination with to_serialize @ 2026-07-15 01:53 Michael Paquier <michael@paquier.xyz> 0 siblings, 0 replies; 2+ messages in thread From: Michael Paquier @ 2026-07-15 01:53 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Rework pgstat_write_statsfile() in combination with to_serialized_data Contrary to the from_serialized_data callback used by the pgstats reads at startup, the to_serialized_data callback used for the pgstats writes matched with pgstat_write_statsfile(), by not returning a boolean status, expecting a ferror() failure to deal with the discard of the stats file should an error happen while writing the stats. This was slightly confusing designed this way. Things are changed in this commit with: - to_serialized_data now returns a boolean status on a write failure. pgstat_write_statsfile() detects that and switches to failure mode instead of continuing to process the entries to write, speeding up the shutdown. - pgstat_write_statsfile() now uses STATS_DISCARD if a failure happens, to let the registered callbacks directly know that something is wrong, and that things need to be cleaned up. This gives a better error path detection for custom stats kinds. For example, they do not have to rely solely on the expectation of an ferror() for an auxiliary file. This new set of behaviors matches with what is already done in pgstat_read_statsfile() for the finish() callback (DISCARD on failure, READ on success) and the from_serialized_data with a status returned. Author: Sami Imseih <samimseih@gmail.com> Discussion: https://postgr.es/m/CAA5RZ0sMgOvuhpb2P=KSJOjgjC6AfUu+GYcu9mHar-y_Xtd=Pg@mail.gmail.com Backpatch-through: 19 Branch ------ REL_19_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/0892319c65e7d7458ee8fb902618491aaa0e4734 Modified Files -------------- src/backend/utils/activity/pgstat.c | 34 ++++++++++++++++++---- src/include/utils/pgstat_internal.h | 5 ++-- .../test_custom_stats/test_custom_var_stats.c | 29 +++++++++++------- 3 files changed, 49 insertions(+), 19 deletions(-) ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2026-07-15 01:53 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2026-07-15 01:53 pgsql: Rework pgstat_write_statsfile() in combination with to_serialize Michael Paquier <michael@paquier.xyz> 2026-07-15 01:53 pgsql: Rework pgstat_write_statsfile() in combination with to_serialize Michael Paquier <michael@paquier.xyz>
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