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

  • From: Tim Gorman <tim@xxxxxxxxx>
  • To: VIVEK_SHARMA@xxxxxxxxxxx
  • Date: Fri, 20 Jun 2008 10:46:25 -0600

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.

But even sorting by "prsela,exeela,fchela" misses a huge chunk of time, usually accounted to "log file sync", that occurs when the transaction commits. Just an anomaly of the aged and band-aided TKPROF program...

I would suggest searching for the phrase "log file sync" in your TKPROF report and finding where your transaction is committing, and seeing if you have huge waits there. Just bear in mind how redo is generated by a session and how it is flushed to the online redo log files and when. Reviewing most of the excellent articles on Steve Adams' website at http://www.ixora.com.au on LGWR and "log file sync" would be useful. In particular, his script "lgwr_waits.sql" (I think that's what it's called) and the "sync wait ratio" might be illuminating...




Quoting VIVEK_SHARMA <VIVEK_SHARMA@xxxxxxxxxxx>:

Folks

Why the 13 RE-parses, when using Bind Variables?

Cheers

________________________________
Sent: Thursday, June 12, 2008 4:57 PM
Folks

Benchmarking a Banking Java Application using Oracle thin driver to connect to the Database. OLTP Nature of Transactions
NOTE - Dedicated Server process connections to Database.

INSERT INTO SaleBackEnd(SaleBackEnd.ATMPinStatus, ... VALUES  ( :1, :2, ... )

Below is the SQL Trace taken under Tran. Load (10046 at Level 12).
Qs Is the INSERT facing performance issues?

CONFIG:-
HP-UX
Oracle 10.2

Will share Detailed SQL Trace file, as needed.

Cheers & Thanks indeed

Vivek

P.S. SQL Trace under Load :-

call count cpu elapsed disk query current rows ------- ------ -------- ---------- ---------- ---------- ---------- ---------- Parse 13 0.00 0.00 0 0 0 0 Execute 13 0.20 0.57 0 29 184 13 Fetch 0 0.00 0.00 0 0 0 0 ------- ------ -------- ---------- ---------- ---------- ---------- ---------- total 26 0.20 0.58 0 29 184 13

Misses in library cache during parse: 0
Optimizer mode: ALL_ROWS
Parsing user id: 26  (CRMUSER)

Rows     Execution Plan
-------  ---------------------------------------------------
      0  INSERT STATEMENT   MODE: ALL_ROWS


Elapsed times include waiting on following events:
  Event waited on                             Times   Max. Wait  Total Waited
  ----------------------------------------   Waited  ----------  ------------
  SQL*Net message to client                      13        0.00          0.00
  SQL*Net message from client                    13        0.30          0.35


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