Re: BUG #7819: missing chunk number 0 for toast value 1235919 in pg_toast_35328

Pius Chan <pchan@contigo.com> writes:
> Hi Tom,
> Yes, we start seeing this ERROR after upgrade to 9.1.7. The ERROR is from the "cluster jms_messages" command.  Last
night,the ERROR happened three times: 

> (1) at 00:20:01
>  ERROR:  missing chunk number 0 for toast value 1239124 in pg_toast_35328

> (2) at 00:25:01
> ERROR:  missing chunk number 0 for toast value 1239124 in pg_toast_35328

> (3) at 00:35:01
>  ERROR:  missing chunk number 0 for toast value 1241022 in pg_toast_35328

> The "cluster jms_messages" runs every 5 minutes. However, so far, it seems that the ERROR happens at about mid-night
and35328 is the toast area of the "jms_message" table: 

So what else is this application doing around midnight?  In particular,
it seems like something must've happened between 00:15 and 00:20 to
create the problem with OID 1239124, and then something else happened
between 00:25 and 00:30 to get rid of it.  And then a similar sequence
happened between 00:30 and 00:40 involving OID 1241022.  Most likely the
trigger events are application actions against jms_messages, but we have
no info about what.  (It's also possible that autovacuums of
jms_messages are involved, so you might want to crank up your logging
enough so you can see those in the postmaster log.)

I had first thought that this might have something to do with the
toast-value-processing changes we made in CLUSTER a year or so ago,
but a look in the commit logs confirms that those patches were in 9.1.3.
So I have no idea what might've broken between 9.1.3 and 9.1.7.  We
need data, or even better an actual test case.

            regards, tom lane