Has anyone actually measured the performance overhead of storing visibility info in indexes? I know the space overhead sounds daunting, but even if it doubled the size of the index in many cases that'd still be a huge win over having to scan the heap as well as the index (esp. for things like count(*)). There would also be overhead from having to update the old index tuple, but for the case of updates you're likely to need that page for the new index tuple anyway.

I know this wouldn't work for all cases, but ISTM there are many cases where it would be a win.
Jim Nasby                                            [EMAIL PROTECTED]
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)

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