Brad Nicholson <bnichols@xxxxxxxxxxxxxxx> writes: > Scenario - a large table was not being vacuumed correctly, there now ~ > 15 million dead tuples that account for approximately 20%-25% of the > table. Vacuum appears to be stalling - ran for approximately 10 hours > before I killed it. I hooked up to the process with gdb and this looks > a bit suspicious to me. Looks perfectly normal to me. Reads in btbulkdelete are exactly where I'd expect 7.4's vacuum to be spending the bulk of its wait time on a large table, because that's a logical-order traversal of the index, and cannot benefit from any sequential-access advantage. (As of 8.2 we are able to do this with a physical-order traversal, which can be a whole lot faster.) If you can afford to lock the table against writes for awhile, reindexing might help by bringing the index back into physical order. regards, tom lane
