Re: Non-linear Performance

From: "Peter A(dot) Daly" <petedaly(at)ix(dot)netcom(dot)com>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: Non-linear Performance
Date: 2002-05-30 14:37:56
Message-ID: 3CF63944.1060000@ix.netcom.com
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Peter A. Daly wrote:

>
> Tom Lane wrote:
>
>>
>> Btree index build is primarily a sort, so cannot have better than
>> O(n*log(n)) performance for random data. Not sure why you'd expect
>> linearity.
>>
>> Increasing SORT_MEM would help the constant factor, however...
>>
> What is the most amount of SORT_MEM it makes sense to allocate?
> Pretend the ONLY thing I care about is BTREE index creation time. (2
> gigs of RAM on my DB machine.) Disk IO is not a bottleneck.

Another though. If postgres has one of my CPU's at near 100%, does that
mean I can't get any more performance out of it? Still, how big can I
make sort_mem?

-Pete

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