On 8/14/07, Gregory Stark <[EMAIL PROTECTED]> wrote: > > "Tom Lane" <[EMAIL PROTECTED]> writes: > > > > > Doesn't this design completely fail to take index bloat into account? > > Repairing heap fragmentation does not reduce the need for VACUUM to work > > on the indexes. > > Index bloat is a bit of an open issue already. Because page splits already > prune any LP_DELETEd pointers any busy index keys will be pruned already.
However any index keys which have not been the subject of an index lookup -- > and that includes keys which are only accessed by bitmap-index-scans -- > won't > be pruned. > > So we don't really know how much bloat is currently in an index. Perhaps > we > need a new statistic which gets updated whenever a page split prunes > LP_DELETEd pointers (or perhaps when LP_DELETE is set?). I agree here. As a first step, may be can address the heap space usage statistics and then take up index stats separately. Index bloat would carry a different weight in triggering autovacuum. I shall code up a patch which tracks the dead space in the heap and trigger autovac based on that. Thanks, Pavan -- Pavan Deolasee EnterpriseDB http://www.enterprisedb.com
