Re: BUG #1242: Major bug in pgSQL

Gaetano Mendola <mendola@bigfoot.com> writes:
> When you are experiencing this show us the result of this query:
> select cmax, cmin, xmax, xmin, * from <table> where <your condition>;

Also, please, the ctid and oid columns (but leave out oid if you made
the table WITHOUT OIDS).

Also, if the condition is one that will normally use an index, try
the same query with and without "set enable_indexscan = off".  It
could be that a corrupted index would cause the query to visit the
same rows multiple times (or miss rows!).

It might be a good idea to REINDEX the primary-key index on the table,
but I would counsel not doing so until we have more data on what's
happening.  If the problem is index corruption then REINDEX would
destroy all the evidence ...

            regards, tom lane