On Fri, Oct 27, 2023 at 10:23:34AM +0530, Bharath Rupireddy wrote: > A possible way is to move existing pgstat_count_slru_flush in > SimpleLruWriteAll closer to pg_fsync and WAIT_EVENT_SLRU_SYNC in > SlruPhysicalWritePage, remove WAIT_EVENT_SLRU_FLUSH_SYNC completely, > use WAIT_EVENT_SLRU_SYNC in SlruSyncFileTag and count the flushes in > SlruSyncFileTag. This aggregated way is much simpler IMV. > > Another possible way is to have separate stat variables for each of > the SLRU flushes WAIT_EVENT_SLRU_SYNC and WAIT_EVENT_SLRU_FLUSH_SYNC > and expose them separately in pg_stat_slru. I don't like this > approach.
This touches an area covered by a different patch, registered in this commit fest as well: https://www.postgresql.org/message-id/camm1awb18ept0whjrjg+-nyhnouxet6zuw0pnyyae+nezpv...@mail.gmail.com So perhaps we'd better move the discussion there. The patch posted there is going to need a rebase anyway once the split with pg_stat_checkpointer is introduced. >> The error message generated for an incorrect target needs to be >> updated in pg_stat_reset_shared(): >> =# select pg_stat_reset_shared('checkpointe'); >> ERROR: 22023: unrecognized reset target: "checkpointe" >> HINT: Target must be "archiver", "bgwriter", "io", "recovery_prefetch", or >> "wal". > > +1. Changed in the attached v10-001. FWIW, having a test case in > stats.sql emitting this error message and hint would have helped here. > If okay, I can add one. > > PS: I'll park the SLRU flush related patch aside until the approach is > finalized. I'm posting the pg_stat_checkpointer patch as v10-0001. Thanks. That seems OK. I don't have the wits to risk my weekend on buildfarm failures if any, so that will have to wait a bit. -- Michael
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