Re: New to PostgreSQL, performance considerations

On Dec 15, 2006, at 17:53 , Ron wrote:

> At 09:50 AM 12/15/2006, Greg Smith wrote:
>> On Fri, 15 Dec 2006, Merlin Moncure wrote:
>>
>>> The slower is probably due to the unroll loops switch which can
>>> actually hurt code due to the larger footprint (less cache
>>> coherency).
>>
>> The cache issues are so important with current processors that I'd
>> suggest throwing -Os (optimize for size) into the mix people
>> test. That one may stack usefully with -O2, but probably not with
>> -O3 (3 includes optimizations that increase code size).
>
> -Os
> Optimize for size. -Os enables all -O2 optimizations that do not
> typically increase code size. It also performs further
> optimizations designed to reduce code size.

So far I have been compiling PostgreSQL and running my pgbench script
manually, but this makes me want to modify my script to run pgbench
automatically using all possible permutations of a set of compiler
flags.

Last I tried GCC to produce 32-bit code on this Opteron system,
though, it complained about the lack of a compiler; can I persuade it
to generate 32-bit code (or 32-bit pointers for that matter) without
going the cross-compilation route?

Alexander.