Re: ** latch free wait contention, log file sync

From: A Joshi <ajoshi977_at_yahoo.com>
Date: Mon, 7 Apr 2008 18:49:48 -0700 (PDT)
Message-ID: <562952.10211.qm@web58013.mail.re3.yahoo.com>

Alex,

     Thanks. I did go thru statspack and I am seeing very high number for this and also for log file sync waits. About what is slow : some updates and reports/lookup are running slow and I am investigating those too. Just wanted to know a way to address these. I found on asktom that latch free might be related to bind variable non usage. We do have some ad hoc but those are unavoidable right now so I just want to know if anything else can be done. If someone had similar high waits. Thanks

Alex Gorbachev <ag@oracloid.com> wrote: No offense please but before I type anything else... This is a typical candidate for a reply with reference to (http://catb.org/~esr/faqs/smart-questions.html)

Now back to the topic.

Most *probably* it's not the root cause of you problem but a symptom and there's probably no point fixing the symptom itself. You might get some lessons about the latches from this list but that might not be what you need at this point. I would recommend to provide more details about your issue - starting with what is slow. After that you would have some options like system wide analysis with Statspack/AWR or scope down to a slow functionality if you can and use ASH or extended trace.

So the investigation *might* be like that:

1. Identify what's slow
2. Confirm that latching is your current bottleneck for the functionality that's slow
3. If it's latching indeed, determine which latch it is (might be straightforward in 10g but less obvious in 9i)
4.  Here is when your question below becomes valid with additional  information which latch it is about and rephrased by not asking not how  to increase timeout but how to avoid latching or make waiting on  latches lower.

You might have actually gone through this sequence already but so far I can conclude only the opposite based on how you form the question.

Alex

On 7-Apr-08, at 12:18 PM, A Joshi wrote: Hi,

      Can someone tell ways to improve latch free waits.  It seems to be timing out a lot. Any parameters can be increased? Any  relevant docs/url/info. Thanks
        




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Received on Mon Apr 07 2008 - 20:49:48 CDT