Bruce Momjian <br...@momjian.us> writes: > On Fri, Nov 9, 2012 at 12:50:34AM -0500, Tom Lane wrote: >> The hash_seq_search time is probably mostly associated with >> AtEOXact_RelationCache, which is run during transaction commit and scans >> the relcache hashtable looking for tables created in the current >> transaction. So that's about 50% of the runtime going into that one >> activity.
> Thanks for finding this. What is odd is that I am not seeing non-linear > restores at 16k in git head, so I am confused how something that > consumes ~50% of backend time could still perform linearly. Would this > consume 50% at lower table counts? No, the cost from that is O(N^2), though with a pretty small multiplier. 16K tables is evidently where the cost reaches the point of being significant --- if you went up from there, you'd probably start to notice an overall O(N^2) behavior. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers