Alvaro Herrera <alvherre@xxxxxxxxxxxxxxxxx> writes: > Tom Lane escribió: >> We could set a hard limit at RelationGetNumberOfBlocks * >> MaxHeapTuplesPerPage TIDs, but that is *extremely* conservative >> (it'd work out to allocating about a quarter of the table's actual size >> in bytes, if I did the math right). > Another idea is to consider applying this patch: > http://thread.gmane.org/gmane.comp.db.postgresql.devel.patches/19384/focus=19393 > which is said to reduce the amount of memory needed to store the TID > array. Yeah, but that's orthogonal to the question of how many TID slots we need. >> Given that the worst-case consequence is extra index vacuum passes, >> which don't hurt that much when a table is small, maybe some smaller >> estimate like 100 TIDs per page would be enough. Or, instead of >> using a hard-wired constant, look at pg_class.reltuples/relpages >> to estimate the average tuple density ... > This sounds like a reasonable compromise. Do you want to make it happen? regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org/
