Bharath Rupireddy <bharath.rupireddyforpostg...@gmail.com> writes: > On Wed, Jan 10, 2024 at 10:00 AM Tom Lane <t...@sss.pgh.pa.us> wrote: >> Maybe. I bet just bumping up the constant by 2X or 4X or so would get >> most of the win for far less work; it's not like adding a few more >> LWLocks is expensive. But we need some evidence about what to set it to.
> I previously made an attempt to improve WAL insertion performance with > varying NUM_XLOGINSERT_LOCKS. IIRC, we will lose what we get by > increasing insertion locks (reduction in WAL insertion lock > acquisition time) to the CPU overhead of flushing the WAL in > WaitXLogInsertionsToFinish as referred to by the following comment. Very interesting --- this is at variance with what the OP said, so we definitely need details about the test conditions in both cases. > Unfortunately, I've lost the test results, I'll run them up again and > come back. Please. regards, tom lane