> ISTM that vacuum_xid_failsafe_check() should really be doing something
> similar. For example, it could prorate using
> vacuum_multixact_failsafe_age, calculating a member-space-wise
> threshold to trigger the failsafe at, independent of
> mxid_age(relminmxid) itself.
+1. For the case mentioned in this thread, running
vacuum without index-cleanup did help in their case. So triggering
failsafe based on a member-space-wise threshold sounds like a good idea to me.
I also think exposing the members count [0] will be a good idea
as well. One of the complaints in the postmortem is the lack of
visibility into multixact members.
[0]
https://www.postgresql.org/message-id/flat/CALdSSPi3Gh08NtcCn44uVeUAYGOT74sU6uei_06qUTa5rMK43g%40mail.gmail.com#bfd9ae766ef42f7599258183aa8ddb3b
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Sami Imseih
Amazon Web Services (AWS)
