8.4 Performance improvements: was Re: Proposal of tunable fix for scalability of 8.4

Greg Smith wrote:
> On Thu, 12 Mar 2009, Jignesh K. Shah wrote:
>
>> As soon as I get more "cycles" I will try variations of it but it
>> would help if others can try it out in their own environments to see
>> if it helps their instances.
>
> What you should do next is see whether you can remove the bottleneck
> your test is running into via using a connection pooler. That's what
> I think most informed people would do were you to ask how to setup an
> optimal environment using PostgreSQL that aimed to serve thousands of
> clients. If that makes your bottleneck go away, that's what you should
> be recommending to customers who want to scale in this fashion too.
> If the bottleneck moves to somewhere else, that new hot spot might be
> one people care more about. Given that there are multiple good
> pooling solutions floating around already, it's hard to justify
> dumping coding and testing resources here if that makes the problem
> move somewhere else.
>
> It's great that you've identified an alternate scheduling approach
> that helps on your problematic test case, but you're a long ways from
> having a full model of how changes to the locking model impact other
> database workloads. As for the idea of doing something in this area
> for 8.4, there are a significant number of performance-related changes
> already committed for that version that deserve more focused testing
> during beta. You're way too late to throw another one into that
> already crowded area.
>

On the other hand I have taken up a task of showing 8.4 Performance
improvements over 8.3.
Can we do a vote on which specific performance features we want to test?
I can use dbt2, dbt3 tests to see how 8.4 performs and compare it with
8.3? Also if you have your own favorite test to test it out let me
know.. I have allocated some time for this task so it is feasible for me
to do this.

Many of the improvements may not be visible through this standard tests
so feedback on testing methology for those is also appreciated.
* Visibility map - Reduce Vacuum overhead - (I think I can time vacuum
with some usage on both databases)
* Prefetch IO with posix_fadvice () - Though I am not sure if it is
supported on UNIX or not (but can be tested by standard tests)
* Parallel pg_restore (Can be tested with a big database dump)

Any more features that I can stress during the testing phase?

Regards,
Jignesh

> --
> * Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD

--
Jignesh Shah http://blogs.sun.com/jkshah
The New Sun Microsystems,Inc http://sun.com/postgresql