Re: [PERFORM] Sun Fire T2000 and PostgreSQL 8.1.3

[Anthony Ransley]

Hi Juan Casero, I've found that serial query clients are best served by PostgreSQL running on fast single or dual core processors, ( such as the Athlon FX60 ) rather than expensive n-way systems. I was orginally using an 8-way Xeon computer for a similar serial throughput problem. and i wasn't supprised to find that at least 6 of the 8 processors were idle. The point is, for this type client, you are better off spending the money on the fastest single or dual core processors than a multiway box. Anthony. Juan Casero (FL FLC) wrote: Greetings -   I am testing a Sun Microsystems Sun Fire T2000 demo server at our company.   I want to know if anyone here has any experience with this hardware and postgresql 8.1.3.  I installed the copy of postgresql 8.1.3 from blastwave.org onto this demo box and loaded our production database into it.  This box has a single Ultrasparc T1 cpu with six execution piplelines that can each handle 4 threads.  With the Unix top utility the postgresql server appears to bounce around between the available threads on the system.  For example I run a single large query and I can see the postgresql server sometimes running on cpu/0, other times on cpu/1, cpu/3,....etc up to cpu/23.   However, never is the load for the postgres server reported to be higher than 4.16%.  I did the math and 4.16% x 24 threads = 98.84% cpu load.  So I wonder if the Solaris 10 kernel is somehow throttling the processes so that any single virtual processor can do no more than 4.16% load.  We got this server last week and I was able to install it in our rack just yesterday.   Now I need to see how I can optimize the postgresql server to work on this box.  Does anyone have any suggestions?   I know the postgresql server is not smp aware but I believe parts of it are.  In particular the buffer manager is supposed to scale the performance almost linearly with the number of cpu's (including virtual ones).  I don't know however, if I need to recompile the postgresql server myself to get those benefits.   I am using the version of postgresql 8.1.3 that is available on blastwave.org.  I am also working with the 64 bit version of the database server.   This machine has over 8GB of ram so I was thinking of using the 64 bit version of the postgresql server so I can access ram beyong the 4gb limit imposed by 32 bit addressing.  Any help or recommendations for performance tweaking of postgresql is very much appreciated.     Thanks, Juan