Re: pgsql: Fix a couple of bugs in MultiXactId freezing

Alvaro Herrera wrote:

> One last thing (I hope).  It's not real easy to disable this check,
> because it actually lives in GetNewMultiXactId.  It would uglify the API
> a lot if we were to pass a flag down two layers of routines; and moving
> it to higher-level routines doesn't seem all that appropriate either.
> I'm thinking we can have a new flag in MyPgXact->vacuumFlags, so
> heap_prepare_freeze_tuple does this:
> 
>         PG_TRY();
>         {
>             /* set flag to let multixact.c know what we're doing */
>             MyPgXact->vacuumFlags |= PROC_FREEZING_MULTI;
>             newxmax = FreezeMultiXactId(xid, tuple->t_infomask,
>                                         cutoff_xid, cutoff_multi, &flags);
>         }

Uhm, actually we don't need a PG_TRY block at all for this to work: we
can rely on the flag being reset at transaction abort, if anything wrong
happens and we lose control.  So just set the flag, call
FreezeMultiXactId, reset flag.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
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