On Wed, Mar 25, 2020 at 12:27:28PM -0700, Andres Freund wrote: > On 2020-03-24 16:19:21 -0700, Cary Huang wrote: >> For the replication to make sense, the patch actually disables the WAL >> update at every 32 nextval() calls, so every call to nextval() will >> emit a WAL update for proper replication. This is done by setting >> SEQ_LOG_VALS to 0 in sequence.c > > Why is that needed? ISTM updating in increments of 32 is fine for > replication purposes? It's good imo, because sending out more granular > increments would increase the size of the WAL stream?
Once upon a time, I was looking at the effects of playing with the limit of a WAL record generated every 32 increments for a sequence, and the performance difference is huge and noticeable. -- Michael
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