RE: Speed up massive delete

From: Jim Conboy <Jim.Conboy_at_trw.com>
Date: Thu, 28 Jun 2001 08:00:51 -0700
Message-ID: <F001.0033BFB0.20010628080935@fatcity.com>

Well, that IS true (actually I think
its NOLOGGING for index creation). But if you have massive amounts of INSERTS or DELETES, dropping the index first and then re-creating can help.

If the number of deletes is truly
large, and you've got spare disk space, and the table can be off-line for a while, you might try CTAS (create table as select) using UNRECOVERABLE, to make a second copy of the table with just the rows you want to keep. Then drop or rename the old table, rename the new table, and re-create the indexes with NOLOGGING. In removing 3 million rows from a 9 million row table this method was very fast compared to DELETE.
Jim
>>> TS2017_at_emirates.com 06/28/01 10:58AM
>>>

Yes that is right. rgds <FONT

size=2>amar -----Original Message----- <FONT 
size=2>From: MHately_at_etech-uk.com [<A 
href="mailto:MHately_at_etech-uk.com">mailto:MHately_at_etech-uk.com]

Sent: Thursday, June 28, 2001 6:25 PM To: Multiple recipients of list ORACLE-L Subject: Re: Speed up massive delete
Ron, How does creating indexes as
UNRECOVERABLE save time when you insert data? As far as I'm aware the only operation it will save time on is the initial creation.
Regards, Mike

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Subject: Re: Speed up massive

delete

>-------------------------------------------------------------------|

Jack Drop the indexes first before you
do the deletes will save you time by not creating logs for the indexes being deleted. On my large activity files I have created the indexes as "Unrecoverable" saving time when I add data or delete data. ROR
mªÖªm
>>> nlzanen1_at_EY.NL 06/28/01 05:45AM >>>
Hi All,
I have to do some pretty big deletes on a test environment and they are estimated to take for ever. Are there any options to speed it up? Jack
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Received on Thu Jun 28 2001 - 10:00:51 CDT