Re: prion failed with ERROR: missing chunk number 0 for toast value 14334 in pg_toast_2619 - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: prion failed with ERROR: missing chunk number 0 for toast value 14334 in pg_toast_2619
Date
Msg-id 20210517032147.GH24531@momjian.us
Whole thread Raw
In response to Re: prion failed with ERROR: missing chunk number 0 for toast value 14334 in pg_toast_2619  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Sun, May 16, 2021 at 04:23:02PM -0400, Tom Lane wrote:
> And the reason oldestXID contains that is that pg_upgrade applied
> pg_resetwal, which does this:
>          
>         /*
>          * For the moment, just set oldestXid to a value that will force
>          * immediate autovacuum-for-wraparound.  It's not clear whether adding
>          * user control of this is useful, so let's just do something that's
>          * reasonably safe.  The magic constant here corresponds to the
>          * maximum allowed value of autovacuum_freeze_max_age.
>          */
>         ControlFile.checkPointCopy.oldestXid = set_xid - 2000000000;
>         if (ControlFile.checkPointCopy.oldestXid < FirstNormalTransactionId)
>             ControlFile.checkPointCopy.oldestXid += FirstNormalTransactionId;
> 
> So it seems like we should do some combination of these things:
> 
> 1. Fix FullXidRelativeTo to be a little less trusting.  It'd
> probably be sane to make it return FirstNormalTransactionId
> when it'd otherwise produce a wrapped-around FullXid, but is
> there any situation where we'd want it to throw an error instead?
> 
> 2. Change pg_resetwal to not do the above.  It's not entirely
> apparent to me what business it has trying to force
> autovacuum-for-wraparound anyway, but if it does need to do that,
> can we devise a less klugy method?

Sorry, I wish I could help with this pg_upgrade problem, but I have no
idea why pg_resetwal is doing that.  Pg_upgrade is supposed to be
turning off autovacuum, though I think we have had some cases where it
could not be fully turned off and consumption of many xids caused
autovacuum to run and break pg_upgrade.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  If only the physical world exists, free will is an illusion.




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