Re: Many queries stuck for waiting MultiXactOffsetControlLock on PostgreSQL 9.6.1 replica

On Saturday, July 31, 2021, Rui An <rueian(dot)huang(at)gmail(dot)com> wrote:

>
> I have tried use pg_terminate_backend to kill the stuck prcoesses, but no
> help. They still stuck on waiting for MultiXactOffsetControlLock even if
> the pg_terminate_backend(pid) returns true.
>

All the true is telling you is your process sent the requested signal. It,
and related functions, provide no insight as to if/how receivers of said
signal may have responded.

As for the question at hand - the axiom is “if it ain’t broke don’t fix
it”…but as your system is basically broke you need to fix it by running a
supported version of the software.

And you should also be prepared for the possibility that 9.6 is
discontinued before there is a fix in which case you’d have to upgrade to
v10 (at least) to get said fix.

David J.