Re: Performance issues with large amounts of time-series data
| От | Tom Lane |
|---|---|
| Тема | Re: Performance issues with large amounts of time-series data |
| Дата | |
| Msg-id | 18555.1251312734@sss.pgh.pa.us обсуждение исходный текст |
| Ответ на | Re: Performance issues with large amounts of time-series data (Hrishikesh (हृषीकेश मेहेंदळे) <hashinclude@gmail.com>) |
| Ответы |
Re: Performance issues with large amounts of time-series data
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| Список | pgsql-performance |
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<hashinclude@gmail.com>writes:
> 2009/8/26 Tom Lane <tgl@sss.pgh.pa.us>
>> Do the data columns have to be bigint, or would int be enough to hold
>> the expected range?
> For the 300-sec tables I probably can drop it to an integer, but for
> 3600 and 86400 tables (1 hr, 1 day) will probably need to be BIGINTs.
> However, given that I'm on a 64-bit platform (sorry if I didn't
> mention it earlier), does it make that much of a difference?
Even more so.
> How does a float ("REAL") compare in terms of SUM()s ?
Casting to float or float8 is certainly a useful alternative if you
don't mind the potential for roundoff error. On any non-ancient
platform those will be considerably faster than numeric. BTW,
I think that 8.4 might be noticeably faster than 8.3 for summing
floats, because of the switch to pass-by-value for them.
regards, tom lane
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