Re: local write wait event

  • From: K Gopalakrishnan <kaygopal@xxxxxxxxx>
  • To: chupit@xxxxxxxxx, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 18 Oct 2004 11:42:45 -0700 (PDT)


Sorry for the delay in my reply. I was traveling and was in Beirut for
a week and just returned to Bangalore. You have got some valuable
advice (esp the one from Jonathan). 

Basically  'local write' wait happens (as the name indicates) when the
session is waiting for its local (means writes pending because of its
own operation)  write operation. This could happen typically if the
underlying disc has some serious problems (one of the member disk crash
in RAID-05 - for example, or a controller failure). That is why I might
have said ' you never see this wait in the normal databases!'.  You may
see this during (rarely) Truncating a large table while most of the
buffers of that table in cache. During TRUNCATEs the session has to a
local checkpoint and during this process, the session may wait for
'local write' wait.

We have not documented this in 'Oracle Wait Interface' as it is very
uncommon. May be we can think of adding similar events in the Misc
Waits in next edition.

--- Edgar Chupit <chupit@xxxxxxxxx> wrote:

> Dear List,
> Tracing one of the user sessions I get a lot of waits on "local write
> wait". We are using 10.0.3, I've searched metalink and in the book
> about OWI events, but couldn't find any information about this event,
> while searching in the archives I've found post by K Gopalakrishnan,
> that this event should never be seen in normal databases. Maybe there
> is a more detailed description of this wait event?
> -- 
>  Edgar
> --

Have a nice day !!
Best Regards,
K Gopalakrishnan,
Co-Author: Oracle Wait Interface: Oracle Press 2004.

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