Jan Wieck wrote: > Manfred Koizar wrote: > > On Thu, 21 Aug 2003 21:10:34 +0530, "Shridhar Daithankar" > > <[EMAIL PROTECTED]> wrote: > >>Point I am trying to make is to tune FSM and autovacuum frequency > >>such that you catch all the dead tuples in RAM > > > > You might be able to catch the pages with dead tuples in RAM, but > > currently there's no way to keep VACUUM from reading in all the clean > > pages, which can be far more ... > > Which leads us to a zero gravity vacuum, that does the lazy vacuum for > pages currently available in the buffer cache only. And another pg_stat > column telling the number of tuples vacuumed so that an autovac has a > chance to avoid IO consuming vacuum runs for relations where 99% of the > dead tuples have been caught in memory.
What would be really interesting is to look for dead tuples when you write/discard a buffer page and add them to the FSM --- that is probably the latest time you still have access to the page and has the highest probability of being recyclable. -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(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
