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
(см: обсуждение, исходный текст)
Ответ на: Re: Performance issues with large amounts of time-series data  (Hrishikesh (हृषीकेश मेहेंदळे))
Ответы: Re: Performance issues with large amounts of time-series data  (Greg Stark)
Список: pgsql-performance

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Performance issues with large amounts of time-series data  (Hrishikesh (हृषीकेश मेहेंदळे), )
 Re: Performance issues with large amounts of time-series data  (Tom Lane, )
  Re: Performance issues with large amounts of time-series data  (Hrishikesh (हृषीकेश मेहेंदळे), )
   Re: Performance issues with large amounts of time-series data  (Tom Lane, )
    Re: Performance issues with large amounts of time-series data  (Greg Stark, )
 Re: Performance issues with large amounts of time-series data  (Greg Smith, )
  Re: Performance issues with large amounts of time-series data  (Hrishikesh (हृषीकेश मेहेंदळे), )

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<>writes: 
> 2009/8/26 Tom Lane <>
>> 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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