RE: [Proposal] Add accumulated statistics for wait event

Hello,
You are right, sampling has to be "tuned" regarding the event(s) you want to
catch.

Sampling of 1 second interval is good with treatments that take hours, and
not enough for a minute or a second analysis.

May I invite you to try it, using PASH-viewer (github) with pgsentinel
(github).

Changing pgsentiel.c sampling from 1 second

rc = WaitLatch(MyLatch, WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
ash_sampling_period * 1000L,PG_WAIT_EXTENSION);

to 1/10 second
rc = WaitLatch(MyLatch, WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
ash_sampling_period * 100L,PG_WAIT_EXTENSION);

seems the good balance for me (for analysis periods from a few seconds to
minutes).

Regards
PAscal

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