Re: We're leaking predicate locks in HEAD

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-05-08T03:53:06Z
Lists: pgsql-hackers
Thomas Munro <thomas.munro@gmail.com> writes:
> Reproduced here.  Once the system reaches a state where it's leaking
> (which happens only occasionally for me during installcheck-parallel),
> it keeps leaking for future SSI transactions.  The cause is
> SxactGlobalXmin getting stuck.  The attached fixes it for me.  I can't
> remember why on earth I made that change, but it is quite clearly
> wrong: you have to check every transaction, or you might never advance
> SxactGlobalXmin.

Hm.  So I don't have any opinion about whether this is a correct fix for
the leak, but I am quite distressed that the system failed to notice that
it was leaking predicate locks.  Shouldn't there be the same sort of
leak-detection infrastructure that we have for most types of resources?

			regards, tom lane



Commits

  1. Fix SxactGlobalXmin tracking.