On Thu, Jan 5, 2017 at 6:15 PM, Amit Kapila <amit.kapil...@gmail.com> wrote: > > Your test and results look good, what kind of m/c you have used to > test this. Let me see if I or one of my colleague can do this and > similar test on some high-end m/c.
As discussed with Amit, I have tried to run the same tests with below modification, 1. Increased the total rows to 10milion. 2. Set fsync off; 3. Changed tests as below. Updated all rows at a time. VACUUM FULL; BEGIN; UPDATE testtab SET col2 = md5(random()::text); ROLLBACK; I have run these tests on IBM power2 which have sufficient ram. I have set shared_buffer=32GB. My results show after this patch there is a slight increase in response time (psql \timing was used) for the above update statement. Which is around 5 to 10% delay. Runs Response time in ms for update base. Response Time in ms for update new patch. %INC 1 158863.501 167443.767 5.4010304104 2 151061.793 168908.536 11.8142004312 3 153750.577 164071.994 6.7130915548 4 153639.165 168364.225 9.5841838245 5 149607.139 166498.44 11.2904378179 Under the same condition running original tests, that is, updating rows which satisfy a condition col1 = :value1. I did not see any regression. -- Thanks and Regards Mithun C Y EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers