RE: Migrating 9i to 10g performance issues

From: Juan Miranda <>
Date: Tue, 25 Mar 2008 16:14:03 +0100
Message-Id: <>


Hello. Hope this helps you.  

(Target server has less memory than source ?.)    

You must determine the time to move the biggest table with export/import. Other tables can be imported simultaneausly.  

  • No archivelog, of course.
  • Reduce checkpoints: Very Very big redolog files (5GB), check log_checkpoint_interval, etc.
  • Lots of memory assigned to PGA (>1GB) to recreate indexes.
  • Import es slow, you must do several imports in parallel !
  • Donīt create indexes during import. Download ddlWizard and generate all the DLL. These tool will give you a script to generate all indexes. Split into 2 pieces and execute these 2 pieces at same time. Change parallelism for very big index.
  • Donīt analyze during import. You will do it later in parallel.

You can do export to a pipe and import from a pipe SIMULTANEUSLY. This script do it and execute 4 export/import    

##!/bin/bash -x

for tb in `cat tablas_restores.txt`

echo "Lanzo import en LOCAL: " $tb
echo mkfifo /oracle10/tmp/$tb.pipeimp
echo imp file=/tmp/$tb.pipeimp log=/tmp/imp_$tb.log parfile=/tmp/imp.par  

echo "Lanzo export en REMOTO: " $tb
rsh -l oracle10 nodo1 ". /oracle10/.bash_profile ; mkfifo /oracle10/tmp/$tb.pipeexp ; exp br/br tables=$tb file=/oracle10/tmp/$tb.pipeexp owner=br & rsh -l oracle10 nodo2 'cat > /oracle10/tmp/$tb.pipeimp' < /oracle10/tmp/$tb.pipeexp" &  

echo -----------------------------------------------------

echo "Compruebo numero de imports lanzados" ps aux |grep imp |grep -v grep > /tmp/import.txt imports=`wc -l /tmp/import.txt |awk '{print $1}'` echo "numero de import ejecutandose: " $imports  

#more than 4? wait.
while [ $imports -ge 4 ];
  echo imports $imports mayor que 4 .... wait   sleep 3
  ps aux |grep imp |grep -v grep > /tmp/import.txt   imports=`wc -l /tmp/import.txt |awk '{print $1}'`   echo $imports


  • exp.par USERID=system/pass direct=y buffer=50000000 recordlength=65535 indexes=n constraints=n statistics=none grants=n
  • imp.par USERID=system/pass statistics=none fromuser=USER1 touser=USER1 buffer=50000000 constraints=n grants=n indexes=n ignore=Y


De: [] En nombre de Sandra Becker
Enviado el: martes, 25 de marzo de 2008 12:57 Para: oracle-l
Asunto: Migrating 9i to 10g performance issues

Source DB: Dell server, RHEL4, 12G RAM, Oracle 64 bit SE1, little endian
Target DB: IBM VM on series z9, SLES10, 4G RAM, Oracle EE, big endian
Database is just shy of 1 terabyte in size--70 percent of data is in a single table; total of 212 tables.
12 very large tables, including the monster--most have no column, like a static date, that can be used to logically break the data into "partitions".  

I'm working on procedures to move our production database from the Dell to the IBM. My tests so far indicate that I'm going to need more than 24 hours. Management, in their infinite wisdom, is insisting that it be done in less than 8. It will take as long as it takes, but I'm wondering what I can do to speed things up. So far I've done the following:  

  1. exp/imp - too slow overall
  2. plsql that commits at regular intervals, depending on the size of the table - works very well for all tables under 1M; can load 111 tables in under 2 hours using 2 concurrent sessions. Works for larger tables, but obviously takes much longer. I had 2 sessions doing tables under 1M and 2 doing tables between 1M and 100M concurrently. Didn't try for the 12 tables over 100M.
  3. Direct-path insert - used on the table holding 70 percent of the data. Four months ago I insisted this table have a static date column added. I can logically break the data loads down by date--they want the most current data loaded first, the remainder can be done over a period of days. This is working reasonably well, but having done this same thing once before on this table, I know it will take about a month to get all the data moved based on the constraints I'm working under--can't be done during core business hours, etc.
  4. I put the target database in noarchivelog mode for my testing. Is this a wise move for migrating production during the go live?

Manage has suggested that I leave off old data and load it later. Doesn't work with 95 pecent of the tables because of their structure and foreign key constraints. They also suggested I use both the primary and the standby databases to read from. No way to test this until I go live--constraints again--although this actually was part of my plan from the beginning. Will too many concurrent sessions loading data slow things down too much? What would I look at to determine this? 10g is new to me so I'm not familiar with all the features yet and may be missing something significant.  

Any suggestions are appreciated, other than telling management what they can do with their time constraint. (Already did that.)  



Received on Tue Mar 25 2008 - 10:14:03 CDT

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