Anssi Kääriäinen<anssi.kaariai...@thl.fi> wrote: > A speed test showing a significant drop in performance when using SSI: > > hot2=> create table test_t2 as (select generate_series(0, 1000000)); > hot2=> \timing > begin transaction isolation level repeatable read; > Time: 0.185 ms > hot2=> select count(*) from test_t2; > Time: 134.521 ms > hot2=> select count(*) from test_t2; > Time: 142.132 ms > hot2=> select count(*) from test_t2; > Time: 147.469 ms > hot2=> commit; > hot2=> begin transaction isolation level serializable; > Time: 0.165 ms > hot2=> select count(*) from test_t2; > Time: 349.219 ms > hot2=> select count(*) from test_t2; > Time: 354.010 ms > hot2=> select count(*) from test_t2; > Time: 355.960 ms > hot2=> commit; > > So, count(*) queries are more than twice as slow compared to the old
> serializable transaction isolation level. Thanks for the report. I'll profile tat and see what can be done about it. -Kevin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
