AW: [HACKERS] sort on huge table - Mailing list pgsql-hackers

From Zeugswetter Andreas SEV
Subject AW: [HACKERS] sort on huge table
Date
Msg-id 219F68D65015D011A8E000006F8590C60339E15D@sdexcsrv1.f000.d0188.sd.spardat.at
Whole thread Raw
Responses Re: AW: [HACKERS] sort on huge table  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
> I have compared current with 6.5 using 1000000 tuple-table (243MB) (I
> wanted to try 2GB+ table but 6.5 does not work in this case). The
> result was strange in that current is *faster* than 6.5!
> 
> RAID5
>     current    2:29
>     6.5.2    3:15
> 
> non-RAID
>     current    1:50
>     6.5.2    2:13
> 
> Seems my previous testing was done in wrong way or the behavior of
> sorting might be different if the table size is changed?

This new test case is not big enough to show cache memory contention,
and is thus faster with the new code.
The 2 Gb test case was good, because it shows what happens when 
cache memory becomes rare.

Andreas


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