Thread

1. Postgresql performance on Opteron 8 CPU

   Ericson Smith <eric@did-it.com> — 2005-06-15T14:27:58Z

   Hi,
   
   We've been using a 4 CPU Opteron (16GB) for the past several months, and 
   have now upgraded to an 8 CPU machine with 32GB. Basically, we've taken 
   the postgresql.conf from the 4 way, and used that in the 8 way without 
   making any changes. Shared memory for postgresql in both machines is 
   256MB which seemed to give us the best performance on the 4 way. RHEL 
   4.0 is the OS, and we use the latest SRPMS to install Postgresql.
   
   Running PGBench on the 8 way gives us about 60% of the performance of 
   the 4 way machine. We're running Postgresql 8.03 on both machines. We 
   later installed Postgresql 7.4.6 on the 8 way, and that gave us 
   performance that was comparable (but not in excess) of the 4 way machine.
   
   We're using a fast I/O subsystem (external storage array) for both 
   machines, so things are equivalent on that front. I remember seeing a 
   report on Postgresql issues with 8 CPU machines recently.
   
   Does anyone have suggestions that could improve performance?
   
   -- 
   Warmest regards, 
   
   Ericson Smith
   Programmer
   Did-it Search Marketing
   Raise Your Expectations...
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2. Re: Postgresql performance on Opteron 8 CPU

   Joshua D. Drake <jd@commandprompt.com> — 2005-07-08T22:30:34Z

   > Does anyone have suggestions that could improve performance?
   
   If you have doubled your ram you could definately increase your 
   effective_cache.
   
   As you also doubled your memory you could increase your work_mem but be 
   careful with this setting.
   
   Also just to be certain are you running 32bit or 64bit PostgreSQL?
   
   Sincerely,
   
   Joshua D. Drake
   
   
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