Thread

1. Slow Performance with 7.4.1

   Alex <alex@meerkatsoft.com> — 2004-01-05T08:24:41Z

   Hi,
   I just installed pg 7.4.1 on a new system P4, 3.2Gh HT, 1GB Mem, RH9 and 
   discovered that some of the processes have become extremely slow. Mainly 
   I am talking about a SELECT COUNT(*) or VACUUM.
   
   Before running the same database on a P4. 2Ghz 412MB mem, I got the job 
   done in some cases half the time.
   
   The weird thing however is, that normal inserts seem to be much faster 
   on the new system and I am wondering if it is Postgres or HW related.
   
   Does anyone has an advise ?
   
   Thanks
   Alex
   
   
   
   

2. Re: Slow Performance with 7.4.1

   Douglas McNaught <doug@mcnaught.org> — 2004-01-05T11:53:48Z

   Alex <alex@meerkatsoft.com> writes:
   
   > Hi,
   > I just installed pg 7.4.1 on a new system P4, 3.2Gh HT, 1GB Mem, RH9
   > and discovered that some of the processes have become extremely
   > slow. Mainly I am talking about a SELECT COUNT(*) or VACUUM.
   >
   > Before running the same database on a P4. 2Ghz 412MB mem, I got the
   > job done in some cases half the time.
   >
   > The weird thing however is, that normal inserts seem to be much faster
   > on the new system and I am wondering if it is Postgres or HW related.
   >
   > Does anyone has an advise ?
   
   What kind of disk hardware is on the two systems?  
   
   -Doug
   
   

3. Re: Slow Performance with 7.4.1

   Alex <alex@meerkatsoft.com> — 2004-01-05T12:12:52Z

   The old system has a 80GB, 5200rpm ATA , the new system a 120GB, 7200rpm 
   ATA. The new system should at least not be slower. Also, on the new 
   system I have a separate partition for the database.
   
   If I run a Vacuum or a SELECT COUNT(*) on a larger table (2-6 million 
   records) the systems responds very slow, the screen almost freezes.
   
   Thanks
   Alex
   
   Doug McNaught wrote:
   
   >Alex <alex@meerkatsoft.com> writes:
   >
   >  
   >
   >>Hi,
   >>I just installed pg 7.4.1 on a new system P4, 3.2Gh HT, 1GB Mem, RH9
   >>and discovered that some of the processes have become extremely
   >>slow. Mainly I am talking about a SELECT COUNT(*) or VACUUM.
   >>
   >>Before running the same database on a P4. 2Ghz 412MB mem, I got the
   >>job done in some cases half the time.
   >>
   >>The weird thing however is, that normal inserts seem to be much faster
   >>on the new system and I am wondering if it is Postgres or HW related.
   >>
   >>Does anyone has an advise ?
   >>    
   >>
   >
   >What kind of disk hardware is on the two systems?  
   >
   >-Doug
   >
   >---------------------------(end of broadcast)---------------------------
   >TIP 7: don't forget to increase your free space map settings
   >
   >
   >  
   >
   
   
   
   

4. Re: Slow Performance with 7.4.1

   Douglas McNaught <doug@mcnaught.org> — 2004-01-05T13:44:17Z

   Alex <alex@meerkatsoft.com> writes:
   
   > The old system has a 80GB, 5200rpm ATA , the new system a 120GB,
   > 7200rpm ATA. The new system should at least not be slower. Also, on
   > the new system I have a separate partition for the database.
   >
   > If I run a Vacuum or a SELECT COUNT(*) on a larger table (2-6 million
   > records) the systems responds very slow, the screen almost freezes.
   
   Sounds like you may not have DMA enabled on the newer machine, or
   there is some other kernel problem that slows the disk down.  You
   might try running Bonnie or a similar disk benchmark to make sure you
   are getting the right disk performance.
   
   -Doug
   
   

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   Jiri D. Hoogeveen <jiri@pro.nl> — 2004-01-05T14:17:46Z

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6. Re: Slow Performance with 7.4.1

   Alex <alex@meerkatsoft.com> — 2004-01-05T15:50:05Z

   Yup, DMA is not enabled, probably that is the problem. Tried to enable 
   it but get  an error HDIO_SET_DMA failed: Operation not permitted.
   
   Thanks for the hint.
   Alex
   
   Doug McNaught wrote:
   
   >Alex <alex@meerkatsoft.com> writes:
   >
   >  
   >
   >>The old system has a 80GB, 5200rpm ATA , the new system a 120GB,
   >>7200rpm ATA. The new system should at least not be slower. Also, on
   >>the new system I have a separate partition for the database.
   >>
   >>If I run a Vacuum or a SELECT COUNT(*) on a larger table (2-6 million
   >>records) the systems responds very slow, the screen almost freezes.
   >>    
   >>
   >
   >Sounds like you may not have DMA enabled on the newer machine, or
   >there is some other kernel problem that slows the disk down.  You
   >might try running Bonnie or a similar disk benchmark to make sure you
   >are getting the right disk performance.
   >
   >-Doug
   >
   >
   >  
   >
   
   
   
   

7. Re: Slow Performance with 7.4.1

   Thomas Beutin <tyrone@laokoon.in-berlin.de> — 2004-01-05T16:17:08Z

   On Tue, Jan 06, 2004 at 12:50:05AM +0900, Alex wrote:
   > Yup, DMA is not enabled, probably that is the problem. Tried to enable 
   > it but get  an error HDIO_SET_DMA failed: Operation not permitted.
   probably You have no support for Your boards chipset enabled. You
   can do this ether by loading the proper module or compiling this
   into Your kernel.
   
   Hope this helps.
   
   Greetings,
   -tb
   -- 
   Thomas Beutin                             tb@laokoon.IN-Berlin.DE
   Beam me up, Scotty. There is no intelligent live down in Redmond.
   
   

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   Steven Vajdic <svajdic@asc.corp.mot.com> — 2004-01-05T22:47:11Z

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