Re: Need help understanding a performance problem

On Thu, 17 Jul 2003 20:27:49 +0200, Svend Jensen <Svend.S.Jensen_at_it.dk> wrote:

>>
>Hi Harry,
>db file sequential read event is (contradictionary to the name of the
>event) is blocks gotten by index rowid, blocks gotten by index lookup.
>Scattered read is full table scans, in case of dropped or missing index.
>
>Seems You are having a disk i/o problem or a hot spot - the same blocks
>are read over and over again from disk.
>Check by selecting repeat from v$session_wait with the sid of a slow
>session (or all sessions). The dominating (non idle) event is Your
>target to fix.
>It could be file read, p1 is file number, p2 is block number, p3 is
>number of blocks to read. Check the meaning of values in P1-3 in the
>v$event_name view.
>
>If it is disk i/o, use OS tool to monitor like wmstat, iostat or......?
>v$filestat is not to be relied upon on all versions.
>You didn't mention your version and OS by any chance, did you?
>

Sorry, forgot that part:

Both are Oracle 8.1.7, on Solaris 2.6.

When I ran your select, I got a result that doesn't make sense to me:

EVENT SQL*Net more data from client P1TEXT driver id
P1 675562835
P1RAW 28444553
P2TEXT #bytes
P2 4457
P2RAW 00001169
P3TEXT
P3 0
P3RAW 00
WAIT TIME -2
SECONDS IN WAIT 80
STATE WAITED UNKNOWN TIME This looks like a network issue, but sequential disk reads are so out of whack. Or is the network client waiting on the disk reads?

Thanks,
Harry Boswell Received on Thu Jul 17 2003 - 15:21:54 CDT