Re: strange oradebug from log file sync wait

HP-UX scheduler may cause similar problems. Did you installed latest PHKL scheduler cumulative patch?

Regards
Andrey Nikolaev
http://andreynikolaev.wordpress.com

>
> DB: 11.1.0.7
> HP-Unix
>
>
> We have a database used for ETL/data loads and then the data is fed to an
> oltp. We had performance issues on it yesterday and noticed that the waits
> were on log file sync. The day before we did a comparable data load
> without
> issue. So we ran an AWR report during each period and a differential awr
> report. We noticed that the day before we were handling 50% more
> redo/second
> during a similiar load and time of day. Nothing has changed. We looked at
> other waits and nothing else seems to be standing out. From there we ran
> an
> oradebug hanganalyze 2 and noticed something odd. It seems that the chains
> are all pointing back to the asynchronous IO. We have run 10046 trace to
> look at timing events on the waits and they appear to be longer than they
> should. We have referred this back to the system admins to see what they
> can
> tell us.I tried to google around and look on the oracle support site, but
> I
> do not see much about the async disc IO event. There is an oracle
> background
> process that strictly has this event and when I ran a 10046 trace on it, I
> did not see anything that would immediately lead me to believe there are
> issues. oracle support does briefly mention a bug related to ksfd
> immediately after a patch, but we have not applied a patch recently.
>
> Has anyone seen a hang analyze like this?
>
> Chains most likely to have caused the hang:
> [a] Chain 1 Signature: 'ksfd: async disk IO'<='log file sync'
> Chain 1 Signature Hash: 0x1016ca92
> Chain 2 Signature: 'ksfd: async disk IO'<='log file sync'
> Chain 2 Signature Hash: 0x1016ca92
> [c] Chain 3 Signature: 'ksfd: async disk IO'<='log file sync'
> Chain 3 Signature Hash: 0x1016ca92
>
>
>
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