public inbox for [email protected]help / color / mirror / Atom feed
measuring WAL creation 3+ messages / 2 participants [nested] [flat]
* measuring WAL creation @ 2024-08-02 19:16 Scott Ribe <[email protected]> 0 siblings, 1 reply; 3+ messages in thread From: Scott Ribe @ 2024-08-02 19:16 UTC (permalink / raw) To: Pgsql-admin <[email protected]> I'd like to measure both the amount of WAL created by a long series of data modifications and the compressed size of the generated WAL files. I suppose I need to set wal_keep_size high, and pay attention to segment numbers to make sure it was high enough. Then I can look at segments created while the commands were running. But question: can I simply delete all WAL after a clean shutdown? -- Scott Ribe [email protected] https://www.linkedin.com/in/scottribe/ ^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: measuring WAL creation @ 2024-08-02 20:29 Tom Lane <[email protected]> parent: Scott Ribe <[email protected]> 0 siblings, 1 reply; 3+ messages in thread From: Tom Lane @ 2024-08-02 20:29 UTC (permalink / raw) To: Scott Ribe <[email protected]>; +Cc: Pgsql-admin <[email protected]> Scott Ribe <[email protected]> writes: > I'd like to measure both the amount of WAL created by a long series of data modifications and the compressed size of the generated WAL files. > I suppose I need to set wal_keep_size high, and pay attention to segment numbers to make sure it was high enough. Then I can look at segments created while the commands were running. > But question: can I simply delete all WAL after a clean shutdown? As a general rule, never do that manually --- the risk/reward ratio is unattractive. A checkpoint will release all safely-releasable WAL. You can checkpoint via a shutdown if you insist, but a plain CHECKPOINT command should be enough. regards, tom lane ^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: measuring WAL creation @ 2024-08-02 21:13 Scott Ribe <[email protected]> parent: Tom Lane <[email protected]> 0 siblings, 0 replies; 3+ messages in thread From: Scott Ribe @ 2024-08-02 21:13 UTC (permalink / raw) To: Tom Lane <[email protected]>; +Cc: Pgsql-admin <[email protected]> > On Aug 2, 2024, at 2:29 PM, Tom Lane <[email protected]> wrote: > > Scott Ribe <[email protected]> writes: >> I'd like to measure both the amount of WAL created by a long series of data modifications and the compressed size of the generated WAL files. >> I suppose I need to set wal_keep_size high, and pay attention to segment numbers to make sure it was high enough. Then I can look at segments created while the commands were running. > >> But question: can I simply delete all WAL after a clean shutdown? > > As a general rule, never do that manually --- the risk/reward ratio is > unattractive. A checkpoint will release all safely-releasable WAL. > You can checkpoint via a shutdown if you insist, but a plain > CHECKPOINT command should be enough. Oh, I thought at a checkpoint it would keep around some minimum, wal_keep_size, or wal_min_size. But I suppose I could set those to 0 if needed. Anyway, this would be a database solely for the purpose of running these tests, starting empty, so risk is not a factor unless I keep corrupting it between test stages ;-) ^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2024-08-02 21:13 UTC | newest] Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2024-08-02 19:16 measuring WAL creation Scott Ribe <[email protected]> 2024-08-02 20:29 ` Tom Lane <[email protected]> 2024-08-02 21:13 ` Scott Ribe <[email protected]>
This inbox is served by agora; see mirroring instructions for how to clone and mirror all data and code used for this inbox