Re: That EXPLAIN ANALYZE patch still needs work
От | Simon Riggs |
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Тема | Re: That EXPLAIN ANALYZE patch still needs work |
Дата | |
Msg-id | 1149847912.2691.240.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: That EXPLAIN ANALYZE patch still needs work (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: That EXPLAIN ANALYZE patch still needs work
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Список | pgsql-hackers |
On Thu, 2006-06-08 at 17:21 -0400, Tom Lane wrote: > Alvaro Herrera <alvherre@commandprompt.com> writes: > > Tried on two machines. The first (Turion64 laptop) gives 44-45 ms for > > the SELECT, and 50-51 ms for the EXPLAIN ANALYZE. > > > The second machine, desktop Celeron 533, gives 197-200 ms for the SELECT > > and 788-790 for the EXPLAIN ANALYZE. I guess this is the reproduction > > you were looking for. > > Do you have oprofile installed on these? Comparing oprofile results > might give some more insight where the time is going. On my office PC the overhead from EA is about 20%. stracing a backend, I also notice that on a 1.5 million row table we make only 39158 calls to gettimeofday, on a table of 24591 blocks. I'm thinking that the instrumentation overhead has been reduced as a result of the page-at-a-time heap scans we now have? -- Simon Riggs EnterpriseDB http://www.enterprisedb.com
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