On Aug 27, 2007, at 4:08 PM, Tom Lane wrote:
Kamil Srot <kamil.srot@xxxxxxxxx> writes:
# select xmin, age(xmin) from pg_class;
xmin | age
-----------+------------
2 | 2147483647
2 | 2147483647
2 | 2147483647
2 | 2147483647
2 | 2147483647
2 | 2147483647
236838019 | 539453
2 | 2147483647
2 | 2147483647
231899309 | 5478163
etc.
I see no indication here that there's anything wrong at all.
The rows with xmin = 2 (ie, FrozenTransactionID) are evidently
pg_class
rows that have never been modified since the database was created.
There isn't anything wrong with them. age() is returning INT_MAX for
them to denote that they are "infinitely far in the past", but they
are
in no danger of being invalidated by wraparound.
The newer rows indicate that your current transaction counter is
around
237 million, which is barely a tenth of the way to wraparound. While
it's conceivable that it already wrapped around (ie, you've really
executed 237 million plus some multiple of 2^32 transactions), I think
it's more probable that no wraparound has happened and your problem is
entirely unrelated to that. I believe this in part because having
just
one table "disappear" is not the likely result of an XID wraparound
problem, and in part because 8.2 has got very strong defenses against
allowing wraparound failure to occur: it will shut down first, and it
will do a whole lot of bleating and autovacuuming before that.
You haven't yet showed us any details of what happens. What
exactly do
you mean by the table "disappearing"? Can you select from it? Do you
see a row for it in pg_class?
regards, tom lane
Also, in your original post you mentioned a "proprietal CMS system".
Is this proprietary to your company or one that you've purchased?
The fact that the same table going on multiple dbs all being run by
that CMS system certainly makes it worthy of suspicion.
Erik Jones
Software Developer | Emma®
erik@xxxxxxxxxx
800.595.4401 or 615.292.5888
615.292.0777 (fax)
Emma helps organizations everywhere communicate & market in style.
Visit us online at http://www.myemma.com
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