Re: Errors on missing pg_subtrans/ files with 9.3

On 2013-11-12 11:25:03 -0500, Stephen Frost wrote:
> * J Smith (dark.panda+lists@gmail.com) wrote:
> > I've recently upgraded a number of servers from PostgreSQL 9.2.5 to
> > 9.3.1 and have started getting the following errors every couple of
> > hours along with some failed transactions.
> 
> How was this upgrade done?  If you used pg_upgrade, what version of the
> pg_upgrade code did you use?  As I recall, there was a bug in older
> versions which could exhibit in this way..

He referred to using pg_dumpall/pg_dump. But that bug was erroring out
on pg_clog, not pg_subtrans, right?

Getting such errors on pg_subtrans indicates corruption or a bug
somewhere, we don't do them if the to-be-looked up xid is older than
TransactionXmin and we zero pg_subtrans at restarts.

My gut feeling is thats it's related to foreign key locks doing
XactLockTableWait()s on too old transactions or something like that.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services