There was a regression introduced in 9.2 that effects the creation and loading of lots of small tables in a single transaction.
It affects the loading of a pg_dump file which has a large number of small tables (10,000 schemas, one table per schema, 10 rows per table). I did not test other schema configurations, so these specifics might not be needed to invoke the problem. It causes the loading of a dump with "psql -1 -f " to run at half the previous speed. Speed of loading without the -1 is not changed. The regression was introduced in 39a68e5c6ca7b41b, "Fix toast table creation". Perhaps the slowdown is an inevitable result of fixing the bug. The regression was removed from 9_1_STABLE at commit dff178f8017e4412, "More cleanup after failed reduced-lock-levels-for-DDL feature". It is still present in 9_2_STABLE. I don't really understand what is going on in these patches, but it seems that either 9_1_STABLE now has a bug that was fixed and then unfixed, or that 9_2_STABLE is slower than it needs to be. The dump file I used can be obtained like this: perl -le 'print "set client_min_messages=warning;"; print "create schema foo$_; create table foo$_.foo$_ (k integer, v integer); insert into foo$_.foo$_ select * from generate_series(1,10); " foreach $ARGV[0]..$ARGV[0]+$ARGV[1]-1' 0 10000 | psql > /dev/null ; pg_dump > 10000.dump Cheers, Jeff -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
