RE: Huge import takes a long time
- From: "Marquez, Chris" <cmarquez@xxxxxxxxxxxxxxxx>
- To: <Michael.Kline@xxxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 21 Jul 2005 11:16:44 -0400
Without knowing or looking at the specifics of your situation or the
limitations of partition IMPorts, these are small and large things that have
helped me and I have used many times in the past and even within the last week
to complete a large db migration to a new platform (boy, I will be glad when
RMAN can just move/copy/clone (data) files from OS-a to OS-b!!!)
Be forewarned about using "_[parameter]" parameters!
Using them and having a db/server crash during use, means corrupt database for
sure.
Un-set them when finished *AND* make sure you can switch / cycle all redo (arch
logs)...test, test, test.
You have been warned.
Good luck...hth
Chris Marquez
Oracle DBA
-----------------------
Faster IMPORTS
-----------------------
Set IMP parameter COMMIT = Y.
Set IMP parameter RECORDLENGTH >= EXP RECORDLENGTH value.
Set IMP parameter BUFFER = MB (Set in the MB range not KB range)
Set IMP parameter STATISTICS = NONE (9i, n/a 8i)
Set IMP parameter RECALCULATE_STATISTICS = N. (8i, n/a 9i)
Set IMP parameter ANALYZE = N. (8i, n/a 9i)
Set IMP parameter INDEXES = N (Import them later...separately)
Set init.ora parameter LOG_ARCHIVE_START = FALSE *&* alter database
noarchivelog;
Set init.ora parameter _disable_logging = TRUE (Warning, this could be
dangerous and unrecoverable in failure. Backup immediately after import - *
Redo records (to disk) will NOT be generated (redo WAS generated in the log
buffer.) [Even with _disable_logging you still "switch" logs when they get
"full"])
Set init.ora parameter _wait_for_sync = FALSE (Warning, this could be dangerous
and unrecoverable in failure. Backup immediately after import -
_wait_for_sync: Wait_for_sync is an oracle generic parameter which, when set to
false, will allow the system to complete commits without waiting for the
redo-log buffer flushes to complete.)
Make redo logs enormous; 500MB, 1GB, etc.
Use Locally Managed Tablespaces on target database.
Chris Marquez
Oracle DBA
C-(703)507-1421
cmarquez@xxxxxxxxxx
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx on behalf of Kline.Michael
Sent: Thu 7/21/2005 10:00 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Huge import takes a long time
I've got a massive import that takes a long time. This is one I'd love
to drop and recreate the index, but that alone would probably be almost
a terabyte, so that is out of the question.
This is a table partitioned by month and a normal partition is about
20-24GB. As it's coming in, it's getting a lot of I/O wait on the index
datafiles, but only the datafiles of that partition. The index is also
partitioned.
This is now 9.2.0.6, so just how high can you set up the buffer?
Are there any other "tricks"?
As I get to the "end" of the partition my import rate is getting to be
2-3GB per day.
Yuck!!!
Michael Kline
Database Administration
SunTrust Technology Center
1030 Wilmer Avenue
Richmond, Virginia 23227
Outside 804.261.9446
STNet 643.9446
Cell 804.744.1545
<mailto:michael.kline@xxxxxxxxxxxx> michael.kline@xxxxxxxxxxxx
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