On Sat, 24 Apr 2004 10:45:40 -0400, "Shea,Dan [CIS]" <[EMAIL PROTECTED]> wrote: >[...] 87 GB table with a 39 GB index?
>The vacuum keeps redoing the index, but there is no indication as to why it >is doing this. If VACUUM finds a dead tuple, if does not immediately remove index entries pointing to that tuple. It instead collects such tuple ids and later does a bulk delete, i.e. scans the whole index and removes all index items pointing to one of those tuples. The number of tuple ids that can be remembered is controlled by vacuum_mem: it is VacuumMem * 1024 / 6 Whenever this number of dead tuples has been found, VACUUM scans the index (which takes ca. 60000 seconds, more than 16 hours), empties the list and continues to scan the heap ... >From the number of dead tuples you can estimate how often your index will be scanned. If dead tuples are evenly distributed, expect there to be 15 index scans with your current vacuum_mem setting of 196608. So your VACUUM will run for 11 days :-( OTOH this would mean that there are 500 million dead tuples. Do you think this is possible? Servus Manfred ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html