Thanks, Mohammed and Anjo, for your replies.
Now my question is this: given that the table structures (freelists,
etc.) are identical on the two machines, the init.ora parameters are
identical for the two instances, and the machines themselves are nearly
identical (one has 6 CPUs, one 4, but in neither case are the CPUs
anywhere near maxed out), what could be causing the discrepancy?
PB
- Mohammed Shakir <mshakir08816_at_yahoo.com> wrote:
> data block waits is the indicator of freelists contention. I have
> never
> seen a freelists contention, even though I have been running 11
> processing doing inserts using 11 CPUs. I have seen library cache,
> Shared pool and cache buffer chains waits. I took care of buffer busy
> waits and db file sequential reads by increasing freelists, initrans
> to
> 11 and by partitioning the disks. In my case most of the data was
> writting to the same block by as many as 9 processes. I am working on
> a
>
> Sparc 4500 Solaris 2.1.6 with Oracle 8.1.6.0 and 8.1.7.2
>
> Library Shared Pool latch contention was found due to Literal or
> non-shared SQL. Check SQL_text in SQLarea to find literal SQL. Shared
> Pool contention seems to be due to a very large Shared pool. I found
> a
> bug report that indicates that cache buffer chain problem was fixed
> in
> 8.1.3.4 and 9.0.1.3
>
> Cache buffer chain is also an indicator of high physical and logical
> I/O. You can check on that as well.
>
> Hope this helps.
>
> Shakir
>
> --- Paul Baumgartel <treegarden_at_yahoo.com> wrote:
> > Greetings!
> >
> > I am trying to diagnose a performance difference between two
> > databases
> > running the same test. They are similarly configured (same SGA
> size,
> > etc.), and the servers are identical except for the number of CPUs
> > (server A has 4, server B has 6).
> >
> > On database A, INSERT performance is about 190 rows/second.
> >
> > On database B, INSERT performance is over 500 rows/second.
> >
> > I saw some cache buffers chains, buffer busy, and library cache
> latch
> > waits on database A while the test was running, as well as redo log
> > sync waits. The waits didn't seem excessive, though. I checked
> for
> > "checkpoint not complete" redo allocation messages in database A's
> > alert log and found none. The db_block_lru_latches parameter is
> set
> > to
> > one-half the number of CPUs in both machines.
> >
> > I'd much appreciate any suggestions as to what else to check. I
> know
> > that freelists can be an issue (there are multiple sessions
> > performing
> > inserts); how can I check to see if there's freelist contention?
> > Anything else I should investigate?
> >
> > Many TIA,
> >
> >
> >
> >
> >
> > =====
> > Paul Baumgartel, Adept Computer Associates, Inc.
> > paul.baumgartel_at_aya.yale.edu
> >
> >
> >
> >
> >
> > __________________________________________________
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> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.com
> > --
> > Author: Paul Baumgartel
> > INET: treegarden_at_yahoo.com
> >
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>
> =====
> Mohammed Shakir
> CompuSoft, Inc.
> 11 Heather Way
> East Brunswick, NJ 08816-2825
> (732) 672-0464 (Cell)
> (732) 257-6001 (Home)
>
> __________________________________________________
> Do You Yahoo!?
> Yahoo! Tax Center - online filing with TurboTax
> http://taxes.yahoo.com/
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Mohammed Shakir
> INET: mshakir08816_at_yahoo.com
>
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> San Diego, California -- Public Internet access / Mailing
> Lists
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Do You Yahoo!?
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http://taxes.yahoo.com/
--
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--
Author: Paul Baumgartel
INET: treegarden_at_yahoo.com
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Received on Thu Apr 11 2002 - 10:53:27 CDT
