On 12/11/22 22:02, srinivas oguri wrote:
Hi,
We are facing similar problems but the lag is at replay on standby. How can I troubleshoot the replay lag.
Thanks
Srinivas
Well, replay uses CPU and disk I/O. You should monitor both using the OS tools. On Linux, Slowaris and AIX, that would be top, atop, iotop, sar, iostat, nmon, dstat and alike. Also perf tools "perf top" are useful. On Windows, that would be the performance monitor. You first have to figure out where exactly is the bottleneck. Then I would go about looking for newer version that has improved on WAL replay. For instance, PostgreSQL 15 can do parallel replay, which should speed things up, at least a bit. Then, you should test the new version. After that you should decide whether to beef up the hardware with or without upgrade. At any rate, you should treat that like a project. Create a project plan, define milestones, define how you test and what you test and give it a go. You didn't specify the Postgres version or the OS, so a generic answer like this is the best I can come up with. Second best would be the answer to the question of life, universe and everything. Good luck!
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Mladen Gogala
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