Re: Multiple Indexing, performance impact - Mailing list pgsql-general

From Bruce Momjian
Subject Re: Multiple Indexing, performance impact
Date
Msg-id 200106222115.f5MLFtC23833@candle.pha.pa.us
Whole thread Raw
In response to Re: Multiple Indexing, performance impact  (Daniel Åkerud <zilch@home.se>)
Responses Re: Multiple Indexing, performance impact  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
> Holy ultra-violet-active macaronies :)
>
> First I changed it to 256, then I changed it to 1024.
>
> -B 128 is A
> -B 256 is B
> -B 1024 is C
>
> New multiple-index performance data):
>
> 1.    A: 36    B: 32    C: 35
> 2.    A: 69    B: 53    C: 38
> 3.    A: 97    B: 79    C: 40
> 4.    A: 131    B: 98    C: 48
> 5.    A: 163    B: 124    C: 52
> 6.    A: 210    B: 146    C: 66
> 7.    A: 319    B: 233    C: 149
> 8.    A: 572    B: 438    C: 268
> 9.    A: 831    B: 655    C:
> 10.    A: 1219    B: 896    C:
>
> The last test hasn't finished yet, but THANKS! I know the reson now, at
> least... i'll try
> 2048 also.

Strange that even at 1024 performance still drops off at 7.  Seems it
may be more than buffer thrashing.


> -B equals --brutal-performance ? ;)

See my performance article on techdocs.postgresql.org.

--
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