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

From Tom Lane
Subject Re: [HACKERS] sort on huge table
Date
Msg-id 4619.941496543@sss.pgh.pa.us
Whole thread Raw
In response to Re: [HACKERS] sort on huge table  (Tatsuo Ishii <t-ishii@sra.co.jp>)
List pgsql-hackers
Tatsuo Ishii <t-ishii@sra.co.jp> writes:
> RedHat Linux 6.0 (kernel 2.2.5-smp)
> Pentium III 500MHz x 2
> RAM: 512MB
> Disk: Ultra Wide SCSI 9GB x 4 + Hardware RAID (RAID 5).

OK, no problem with inadequate hardware anyway ;-).  Bruce's concern
about simplistic read-ahead algorithm in Linux may apply though.

> Also, I could provide testing scripts to reproduce my tests.

Please.  That would be very handy so that we can make sure we are all
comparing the same thing.  I assume the scripts can be tweaked to vary
the amount of disk space used?  I can't scare up more than a couple
hundred meg at the moment.  (The natural state of a disk drive is
"full" ...)

> I think it depends on the disk space available. Ideally it should be
> able to choice the sort algorithm.

I was hoping to avoid that, because of the extra difficulty of testing
and maintenance.  But it may be the only answer.
        regards, tom lane


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