On 9/16/07, Tom Lane <[EMAIL PROTECTED]> wrote: > > > Couldn't say. Those two were on my mind because the reporters had > allowed me to troll through their table and index files and verify > that there were indeed multiple index pointers to the same table row, > and yet the index itself did not show any indication of corruption. > I had noticed the "clumping" pattern of the doubly-linked rows in > both cases, but hadn't found an explanation. > > This was a nice catch indeed! I remember we fixed a similar issue with VACUUM FULL few months back. Such issues would become prominent with HOT because of early vacuuming and reuse of tuples. Also unlike current VACUUM which runs exclusively on a table (i.e. no two vacuums are allowed to run on a table simultaneously), HOT makes concurrent pruning and vacuuming of a table possible.
In fact, during HOT development and testing cycles, I faced similar race conditions a few times. This is just to keep ourselves aware of the changes introduced by HOT. Hopefully by now we have fixed most of the outstanding bugs in the HOT code (and Tom's eyes would catch the remaining, if any :-)). Fingers crossed. Thanks, Pavan -- Pavan Deolasee EnterpriseDB http://www.enterprisedb.com