RE: Simple SQL waiting on 'log file sync'

  • From: "Marquez, Chris" <cmarquez@xxxxxxxxxxxxxxxx>
  • To: <sharmakdeep_oracle@xxxxxxxxx>
  • Date: Fri, 18 Nov 2005 13:31:00 -0500


Ever wonder why a commit normaly on takes a sec or less even when you are 
committing tons of row chagnes?
Because the rows have already changed!...redo, rollback, and commit logic.
All of this has already been logged to the redo (and archive) logs just waiting 
on you to commit or rollback (that will take time, the rollback).

You are waiting on redo log files access/time...redo contention.
What until you have a lot of sessions doing this and you start having tons of 
latch wait contention.

Is your db busy today? suggestions is tune your redo log file (disks).


Chris Marquez
Oracle DBA

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx on behalf of Deepak Sharma
Sent: Fri 11/18/2005 1:17 PM
To: Kevin Closson
Cc: oracle-l@xxxxxxxxxxxxx
Subject: RE: Simple SQL waiting on 'log file sync'
I am in the process of debugging an application that
uses a PL/SQL procedure that ha sa statement similar
to this.  In my testing, I do have a step to commit,
but that is 'after' this statement. 
What I am noticing is that if I run a trace, there are
'log file sync' messages.

insert.. select statement  <<- generated trace has the
log file sync message

Step 2:
commit <<- I'm not even there yet


--- Kevin Closson <kevinc@xxxxxxxxxxxxx> wrote:

>  >>>
> >>>
> >>>1) Isn't 'log file sync' related to commits? In
> above I am 
> >>>not even commiting.
> um, if you are not committing, what is the purpose
> of this
> select ?

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