Re: High end server and storage for a PostgreSQL OLTP system

Tom Lane wrote:

> Cosimo writes:
>
>>1) What kind of performance gain can I expect switching from
>>    7.1 to 7.4 (or 8.0)? Obviously I'm doing my own testing,
>>    but I'm not very impressed by 8.0 speed, may be I'm doing
>>    testing on a low end server...
>
> Most people report a noticeable speedup in each new release
 > [...]
> I'm surprised that you're not seeing any gain at all.
> What was your test case exactly?  Have you perhaps tuned your app
> so specifically to 7.1 that you need to detune it?

We tend to use the lowest common SQL features that will allow
us to work with any db, so probably the problem is the opposite,
there is no pg-specific overtuning.

Also, the real pg load, that should be my ideal test case,
is somewhat difficult to reproduce (~ 50 users with handhelds
and browser clients).

Another good test is a particular procedure that opens
several (~1000) subsequent transactions, composed of many
repeated selection queries with massive write loads on 6/7
different tables, as big as 300/400k tuples.
Every transaction ends with either commit or rollback state

Indexing here should be ok, for I've analyzed every single query
also under database "stress".

Probably one big issue is that I need to vacuum/reindex too often
to keep db performances at a good(tm) level. I realize that this
has been addressed in several ways with newer PGs.

However, I need to do a lot of application and performance
tests and do them more seriously. Then I'll report the results here.

--
Cosimo