Kevin Hunter <hunteke@xxxxxxxxxxx> writes: > At 1:17p -0400 on 01 Jun 2007, Tyler Durden wrote: >> I find strange that a simple SELECT COUNT(...) is so slow with only >> 700 000 records. > The much more knowledgable will correct me, but the abbr. version is > that it is for data integrity and correctness reasons and the > inherent way in which the MVCC model works. The bottom line is that a "correct" implementation (ie, one that fully respects MVCC behavior) would create enormous overhead, as well as bad contention bottlenecks for concurrent updates. It doesn't seem worth it. If you want a cheap approximate answer, there are a couple of ways to get one, but SELECT COUNT(*) is not that. regards, tom lane
