Bruce Momjian <pgman@candle.pha.pa.us> writes: > Tom Lane wrote: >> Even if you could track the tuple's committed-good status reliably, >> that isn't enough under MVCC.
> I mentioned that: >> (Oh, and you could only update the bit when all active transactions >> are newer than the creation transaction so we know they should all see >> it as visible.) Ah, right, I missed the connection. Hmm ... that's sort of the inverse of the "killed tuple" optimization we put in a release or two back, where an index tuple is marked as definitely dead once it's committed dead and the deletion is older than all active transactions. Maybe that would work. You'd still have to visit the heap when a tuple is in the "uncertain" states, but with luck that'd be only a small fraction of the time. I'm still concerned about the update costs of maintaining these bits, but this would at least escape the index-bloat objection. I think we still have one free bit in index tuple headers... regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly