RE: Slow Export

Ok, so, try running:
truss -c -p <pid of export process>
 
if the export is already running, or:
truss -c exp <all your export parameters>
 
If you're starting up a new export.
 
Let it run for a while, say, 1/2 hour or so.  When you get tired of waiting, 
hit CRTL-C.  (Or, if you want, you can let it run completely.)
If you decide to let it run completely, you could do:
time truss -c -p exp <your export arguments>
 
instead, and the time command will tell you the total elapsed time, which 
you'll want to know.
 
When exp exits, or is cancelled, the truss output will show you the total 
number of system calls and the total time spent servicing them, for each type 
of syscall made by exp.  Now, consider how long exp ran in total, and look at 
the system calls, and where the most time was taken.  If you can see, for 
example, that you ran exp for 1/2 hour, and 25 minutes was spent in write() 
system calls, then, you need to investigate why your writes are so slow.
 
Try it out, if you don't understand the output, try posting it here, and we'll 
see what it tells us.
 
Also, FYI, the oracle session constantly waiting on SQL*Net messages is an 
indication that the bottleneck is in the exp process, and not in the database.  
(This is what Tanel hinted at a few messages ago.)
 
Hope that helps,
 
-Mark
 

-- 
Mark J. Bobak 
Senior Oracle Architect 
ProQuest Information & Learning 

"There are 10 types of people in the world:  Those who understand binary, and 
those who don't." 

 

________________________________

From: Smith, Ron [mailto:rlsmith@xxxxxxx] 
Sent: Tuesday, January 31, 2006 4:26 PM
To: Bobak, Mark; tanel.poder.003@xxxxxxx; ORACLE-L
Subject: RE: Slow Export


No, I found I can run truss.  Just don't know how since we usually can't run 
those type utilities.
The only waits are SQL*NET waits, to and from the client.  About 350 but no 
time associated with the wait.
The export is local.  If done remotely the export runs much faster, back to 
normal times.
 
Thanks!
Ron

        -----Original Message-----
        From: Bobak, Mark [mailto:Mark.Bobak@xxxxxxxxxxxxxxx] 
        Sent: Tuesday, January 31, 2006 3:15 PM
        To: Smith, Ron; tanel.poder.003@xxxxxxx; ORACLE-L
        Subject: RE: Slow Export
        
        
        Hmm....so, they explicitly deperm access to the truss binary?  On most 
Sun servers, it's in /usr/bin, and you should not need root permission to truss 
an oracle owned process.  If you can login as the user who started the database 
(presumably oracle), that should be good enough to do the trace.  Unless they 
really do explicitly deperm the binary.  If that's true, I'd argue that's a 
battle you need to fight, in order to do you job well, you need access to O/S 
level tools like truss.  (I know, I know, easier said than done....;-))
         
        As for the V$SESSION_WAIT output, what do you mean by "looks low"?  Are 
you seeing waits?  What are they?
         
        Also, regarding Tanel's last question, are you exporting locally, or 
over the network?
         
        -Mark
         

        -- 
        Mark J. Bobak 
        Senior Oracle Architect 
        ProQuest Information & Learning 

        "There are 10 types of people in the world:  Those who understand 
binary, and those who don't." 

         

________________________________

        From: oracle-l-bounce@xxxxxxxxxxxxx 
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Smith, Ron
        Sent: Tuesday, January 31, 2006 3:55 PM
        To: tanel.poder.003@xxxxxxx; ORACLE-L
        Subject: RE: Slow Export
        
        
        I had to restart the export.  Ran 8.5 hours this time.
        V$Session_Wait looks low right now.
        I have never used the Truss command.  Unix admins don't give us access.

                -----Original Message-----
                From: oracle-l-bounce@xxxxxxxxxxxxx 
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Tanel Põder
                Sent: Tuesday, January 31, 2006 2:45 PM
                To: ORACLE-L
                Subject: Re: Slow Export
                
                
                Are you exporting over network or locally in the server?
                 
                V$SESSION_EVENT, V$SESSION_WAIT and truss -c should sufficient 
to reveal the cause..
                 
                Tanel.
                 

                        ----- Original Message ----- 
                        From: Smith, Ron <mailto:rlsmith@xxxxxxx>  
                        To: tanel.poder.003@xxxxxxx ; ORACLE-L 
<mailto:oracle-l@xxxxxxxxxxxxx>  
                        Sent: Tuesday, January 31, 2006 2:36 PM
                        Subject: RE: Slow Export
                        
                        
                        There are several exports in different databases, 
exporting various size objects.  The thing is, this started about the middle of 
December.
                        Before that, everything was fine.
                         
                        Ron


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