No enough inserts to bog down the CPUs?
- Paul Baumgartel <treegarden_at_yahoo.com> wrote:
> 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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> > =====
> > Mohammed Shakir
> > CompuSoft, Inc.
> > 11 Heather Way
> > East Brunswick, NJ 08816-2825
> > (732) 672-0464 (Cell)
> > (732) 257-6001 (Home)
> >
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> > Author: Mohammed Shakir
> > INET: mshakir08816_at_yahoo.com
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> 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)
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Yahoo! Tax Center - online filing with TurboTax
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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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Received on Thu Apr 11 2002 - 21:23:21 CDT