Christopher Browne wrote:
Quoth dingxn@xxxxxxxxxxxxxxxxxx (Xiaoning Ding):
When I run multiple TPC-H queries (DBT3) on postgresql, I found the system
is not scalable. My machine has 8GB memory, and 4 Xeon Dual Core processor
( 8 cores in total). OS kernel is linux 2.6.9. Postgresql is 7.3.18. I
I think it might be caused by some contentions. But I do not know postgresql
much. May anybody give me some clue to find the reasons?
Two primary issues:
1. You're running a horrendously ancient version of PostgreSQL. The
7.3 series is Really Old. Newer versions have *enormous*
improvements that are likely to be *enormously* relevant.
Upgrade to 8.2.
8.2 is really much better.
2. There are known issues with the combination of Xeon processors and
PAE memory addressing; that sort of hardware tends to be *way* less
speedy than the specs would suggest.
I think PAE slows each query process. It would not affect scalability.
There have been "context switching" issues on this sort of hardware
that are enormously worsened if you're running on a version of
PostgreSQL that is 4 major releases out of date.
How does PG 8.2 address this issue? by setting processor affinity?
Thanks!
Xiaoning
