Re: [pgsql-performance] Large databases, performance

I wonder if the following changes make a difference:

- compile PostgreSQL with CFLAGS=' -O3 '
- redefine commit delays

also: keep in mind that you might gain a lot of performance by using the 
SPI if you are running many similar queries

try 7.3 - as far as I remeber there is a mechanism which caches recent 
execution plans.
also: some overhead was reduced (tuples, backend startup).

    Hans


>Ok. I am back from my cave after some more tests are done. Here are the 
>results. I am not repeating large part of it but answering your questions..
>
>Don't ask me how these numbers changed. I am not the person who conducts the 
>test neither I have access to the system. Rest(or most ) of the things remains 
>same..
>
>MySQL 3.23.52 with innodb transaction support: 
>
>4 concurrent queries 	:-  257.36 ms
>40 concurrent queries	:-  35.12 ms
>
>Postgresql 7.2.2 
>
>4 concurrent queries 		:- 257.43 ms
>40 concurrent 	queries		:- 41.16 ms
>
>Though I can not report oracle numbers, suffice to say that they fall in 
>between these two numbers.
>
>Oracle seems to be hell lot faster than mysql/postgresql to load raw data even 
>when it's installed on reiserfs. We plan to run XFS tests later in hope that 
>that would improve mysql/postgresql load times. 
>
>In this run postgresql has better load time than mysql/innodb ( 18270 sec v/s 
>17031 sec.) Index creation times are faster as well (100 sec v/s 130 sec). 
>Don't know what parameters are changed.
>
>Only worry is database size. Postgresql is 111GB v/s 87 GB for mysql. All 
>numbers include indexes. This is really going to be a problem when things are 
>deployed. Any idea how can it be taken down? 
>
>WAL is out, it's not counted.
>
>Schema optimisation is later issue. Right now all three databases are using 
>same schema..
>
>Will it help in this situation if I recompile posgresql with block size say 32K 
>rather than 8K default? Will it saev some overhead and offer better performance 
>in data load etc?
>
>Will keep you guys updated..
>
>Regards,
> Shridhar
>
>-----------------------------------------------------------
>Shridhar Daithankar
>LIMS CPE Team Member, PSPL.
>mailto:shridhar_daithankar@persistent.co.in
>Phone:- +91-20-5678900 Extn.270
>Fax  :- +91-20-5678901 
>-----------------------------------------------------------
>
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