Re: MultiXactId error after upgrade to 9.3.4 - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: MultiXactId error after upgrade to 9.3.4
Date
Msg-id 20160617225517.GA157662@alvherre.pgsql
Whole thread Raw
In response to Re: MultiXactId error after upgrade to 9.3.4  (Alvaro Herrera <alvherre@2ndquadrant.com>)
List pgsql-hackers
Alvaro Herrera wrote:
> Andrew Gierth wrote:

> > Why is the correct rule not "check for and ignore pre-upgrade mxids
> > before even trying to fetch members"?
>
> I propose something like the attached patch, which implements that idea.

Here's a backpatch of that to 9.3 and 9.4.

I tested this by creating a 9.2 installation with an out-of-range
multixact, and verified that after upgrading this to 9.3 it fails with
the "apparent wraparound" message in VACUUM.  With this patch applied,
it silently removes the multixact.

I will clean this up and push to all branches after the tagging of
9.6beta2 on Monday.

--
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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