Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Mailing Lists -> Oracle-L -> Re: many seconds waiting for I/O?

Re: many seconds waiting for I/O?

From: amonte <ax.mount_at_gmail.com>
Date: Fri, 27 Jul 2007 13:45:42 +0200
Message-ID: <85c1fb130707270445p1a124386x9969a92acb487bb8@mail.gmail.com>


Hi Norman

If it was sql*net messages why the event shows db file sequential read?

Alex

On 7/27/07, Dunbar, Norman <norman.dunbar_at_environment-agency.gov.uk> wrote:
>
>
> Morning Alex,
>
> >> I have a batch process running and it seems that it's
> >> waiting for I/O all the time, the strange thing is it shows
> >> 400 seconds waits!
> >>
> >> EVENT CONSISTENT_GETS SPID
> >> WAIT_TIME SECONDS_IN_WAIT STATE SEQ#
> >> -------------------------- --------------- ------------
> >> ---------- --------------- ------------------- ----------
> >> db file sequential read 212532 25879
> >> -1 374 WAITED SHORT TIME 892
>
> The STATE of 'waited short time' and the WAIT_TIME of -1 show that this
> is not waiting.
>
> The values of WAIT_TIME are :
>
> Negative : the wait time was unknown.
> Zero : the session is still waiting.
> Positive : the actual time waited.
>
> PLUS for a session that is waiting, the STATE will be 'WAITING'.
>
> You have to take STATE, WAIT_TIME and SECONDS_IN_WAIT together.
>
> A STATE of 'waited short time', as you have, means that the actual wait
> was less than one cent-second and the WAIT_TIME is always shown as -1.
>
> The WAIT_TIME you see is the session's LAST wait time - so whatever
> event it was waiting on previous to the current one would have waited
> nearly 400 seconds. I'd be willing to say that in a batch program it
> would be something like 'SQL*NET message from client' as Oracle has fed
> the batch program a shed load of data which it has to process before
> doing the next lot/query.
>
> Obviously, you'd want to trace the session to be 100% sure ....
>
>
> HTH
>
> Cheers,
> Norman.
>
> Information in this message may be confidential and may be legally
> privileged. If you have received this message by mistake, please notify the
> sender immediately, delete it and do not copy it to anyone else.
>
> We have checked this email and its attachments for viruses. But you should
> still check any attachment before opening it.
>
> We may have to make this message and any reply to it public if asked to
> under the Freedom of Information Act, Data Protection Act or for
> litigation. Email messages and attachments sent to or from any Environment
> Agency address may also be accessed by someone other than the sender or
> recipient, for business purposes.
>
> If we have sent you information and you wish to use it please read our
> terms and conditions which you can get by calling us on 08708 506 506. Find
> out more about the Environment Agency at www.environment-agency.gov.uk
>

--
http://www.freelists.org/webpage/oracle-l
Received on Fri Jul 27 2007 - 06:45:42 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US