Re: Migrating 9i to 10g performance issues

From: Yechiel Adar <>
Date: Tue, 25 Mar 2008 15:20:15 +0200
Message-ID: <>

I think you should look into materialized views. Another option to check is a logical standby database.

I did not worked with either so I do not know if they suitable but I am sure others on the list will kill these options if they do not fit your environment.

Adar Yechiel
Rechovot, Israel

Sandra Becker wrote:
> 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.)
> Thanks.
> Sandy

Received on Tue Mar 25 2008 - 08:20:15 CDT

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