Re: FYI: Load times for a largish DB in 8.2 vs. 8.3 vs. 8.4
От | Tom Lane |
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Тема | Re: FYI: Load times for a largish DB in 8.2 vs. 8.3 vs. 8.4 |
Дата | |
Msg-id | 20305.1245689568@sss.pgh.pa.us обсуждение исходный текст |
Ответ на | Re: FYI: Load times for a largish DB in 8.2 vs. 8.3 vs. 8.4 ("Todd A. Cook" <tcook@blackducksoftware.com>) |
Список | pgsql-general |
"Todd A. Cook" <tcook@blackducksoftware.com> writes: > Todd A. Cook wrote: >> Tom Lane wrote: >>> If you have time to repeat the experiments, it would be interesting to >>> see what happens with consistent default_statistics_target across 8.3 >>> and 8.4. >> >> That would seem to be it: >> 8.4b2 183 min 84,028,897,040 on (defaults, default_statistics_target=10) >> >> I'll run the test on 8.3.7 with default_statistics_target=100 over the weekend. > The results for this are also consistent with Tom's theory: > 8.3.7 205 min 84,048,866,924 on (defaults, default_statistics_target=100) OK, thanks for following up. So this is a different effect from the COPY ring buffer size issue being argued about over on pgsql-hackers. I think we can just say that this one is a price being paid intentionally for better statistics, and if you don't need better statistics you can back off the target setting ... regards, tom lane
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