SELECT constant; takes 15x longer on 9.0?
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From: Takahiro Itagaki on 6 Apr 2010 05:32 Josh Berkus <josh(a)agliodbs.com> wrote: > SELECT 'DBD::Pg ping test'; > > In our test, which does 5801 of these pings during the test, they take > an average of 15x longer to execute on 9.0 as 8.4 ( 0.77ms vs. 0.05ms ). > > Any clue why this would be? Did you use the same configure options between them? For example, --enable-debug or --enable-cassert. Regards, --- Takahiro Itagaki NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Merlin Moncure on 6 Apr 2010 09:07 On Tue, Apr 6, 2010 at 1:47 AM, Josh Berkus <josh(a)agliodbs.com> wrote: > Hackers, > > Continuing the performance test: > > DBD, like a number of monitoring systems, does "pings" on the database > which look like this: > > SELECT 'DBD::Pg ping test'; > > In our test, which does 5801 of these pings during the test, they take > an average of 15x longer to execute on 9.0 as 8.4 ( 0.77ms vs. 0.05ms ). did your pings change? on my machine the query ';' completes in about 0.05ms but any select takes 0.19 - 0.25ms. 0.77 is awfully high -- there has to be an explanation. merlin -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Tom Lane on 6 Apr 2010 10:28 Josh Berkus <josh(a)agliodbs.com> writes: > Continuing the performance test: > DBD, like a number of monitoring systems, does "pings" on the database > which look like this: > SELECT 'DBD::Pg ping test'; > In our test, which does 5801 of these pings during the test, they take > an average of 15x longer to execute on 9.0 as 8.4 ( 0.77ms vs. 0.05ms ). There's something wrong with your test setup. Or, if you'd like me to think that there isn't, provide a self-contained test case. I ran a small program that does for (i = 0; i < 10000; i++) { res = PQexec(conn, "SELECT 'DBD::Pg ping test'"); PQclear(res); } and I only see a few percent difference between HEAD and 8.4.3, on two different machines. (It does appear that HEAD is a bit slower for this, which might or might not be something to worry about.) regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: "David E. Wheeler" on 6 Apr 2010 12:08 On Apr 6, 2010, at 2:32 AM, Takahiro Itagaki wrote: >> In our test, which does 5801 of these pings during the test, they take >> an average of 15x longer to execute on 9.0 as 8.4 ( 0.77ms vs. 0.05ms ). >> >> Any clue why this would be? > > Did you use the same configure options between them? Yes. > For example, --enable-debug or --enable-cassert. No. David -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: "David E. Wheeler" on 6 Apr 2010 12:09
On Apr 6, 2010, at 6:07 AM, Merlin Moncure wrote: >> In our test, which does 5801 of these pings during the test, they take >> an average of 15x longer to execute on 9.0 as 8.4 ( 0.77ms vs. 0.05ms ). > > did your pings change? No. David -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers |