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Re: Monitoring questionable long running sessions

From: Yong Huang <yong321_at_yahoo.com>
Date: 14 Jul 2004 11:41:44 -0700
Message-ID: <b3cb12d6.0407141041.7875d0c5@posting.google.com>


100.17706_at_germanynet.de (Rick Denoire) wrote in message news:<f0c1107f.0407130502.5d8088bd_at_posting.google.com>...
> 9 102 5625 db file sequential
> read file# 33 00000021 block# 213471 000341DF blocks 1 00000001 -1 83911 WAITED
> KNOWN TIME
>
> The last line with the session 112 is the one which is consuming CPU
> at this very moment (the query coord. has an SID of 34).
>
> The wait_event here is said to be "db file sequential read", but as
> far as I can see (and I can see far enough on the OS side), no I/O is
> taking place. It *can not* be waiting for that. It does not even show
> the file being read (it shows only "file#"). Repeating the query
> yields the same result.

Hi, Rick,

Does the seq# 5625 increment? What does this query give?

select * from dba_extents where file_id = 33 and 213471 between block_id and block_id + blocks - 1

It must be an index. Does analyze index <thatindex> validate structure throw an error?

It's possible the session waited on this event 83911 seconds ago and is no longer waiting. Then the problem may be somewhere else. Can you still do a SQL trace on the session (exec dbms_system.set_ev(102,5625,10046,12,''))? If you strace the server process as VC suggested and it doesn't show anything useful, how about ltrace -p <pid>? That's a tool I'm still studying so I may not be able to infer anything from it.

Yong Huang Received on Wed Jul 14 2004 - 13:41:44 CDT

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