RE: INSERT Performance in Benchmark ? ... Basic Qs

  • From: Tanel Poder <tanel.poder.003@xxxxxxx>
  • To: tim@xxxxxxxxx, VIVEK_SHARMA@xxxxxxxxxxx
  • Date: Sat, 21 Jun 2008 02:02:59 +0800

Note that you could be hitting one of the multiple ASSM bugs related to
indexes. Like this one for example:

Bug # 4664513 Slow Insert - Waiting For 'log File Sync' - High 'transaction
Rollback' Stat
( Base bug# 4288876 )

You can easily diagnose it - if you see "transaction rollbacks" in V$SESSTAT
increasing without corresponding "user rollbacks" for that session (you can
use Snapper of taking snapshots). Another symptom is that you see "log file
sync" waits during inserts even if you are not committing (as the session
waits for log file sync when a transaction rollback happens as well).

Tanel Poder

> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx 
> [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Gorman
> Sent: Saturday, June 21, 2008 00:46
> To: VIVEK_SHARMA@xxxxxxxxxxx
> Cc: oracle-l@xxxxxxxxxxxxx; mwf@xxxxxxxx; rjamya; 
> richa03@xxxxxxxxx; Tanel Poder; hrishys@xxxxxxxxxxx; 
> finn.oracledba@xxxxxxxxx; anjo.kolk@xxxxxxxxxxx
> Subject: RE: INSERT Performance in Benchmark ? ... Basic Qs
> One of the pitfalls to TKPROF is that none of the "sort" 
> options (yet) include wait event timings, except perhaps 
> "elapsed", but still not perfectly.
> Please be sure to specify "sort=prsela,exeela,fchela" on the 
> TKPROF command-line for the best results.


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