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Re: Oracle is painfully slow when doing massive INSERTs

From: Mike Mountjoy <michael_at_london.virgin.net>
Date: 1998/03/12
Message-ID: <3507A9E9.E7481200@london.virgin.net>#1/1

You havn't mentioned whether you are running in archivelog mode. If you are take a look at the amount of data written p/sec to your arch logs. There can sometimes be as much 500k/sec being written and its a big I/O bottleneck.

If this is the case then either spread your logs across more spindals or switch off archivelogs for bulk loads (not really a good idea)..

Morten Myrvold wrote:

> Mark Usrey wrote in message <6e6t7j$98d_at_bgtnsc02.worldnet.att.net>...
>
> >You did mention any indices that are kept on you destination table. Large
> >amounts
> >of time can be spent updating the various indices on the destination table
 if
> >they are complex. Also, if the rows being inserted are already ordered,
 updates
> >
> >to indices and be particularly slow.
> >
> >If you are keeping indices, try dropping them before doing the insert, and
 then
> >recreating them afterwards.
>
> Ah, but I have... (dropped them, I mean). Postponing the creation of the
> indices until *after* the data had been loaded resulted in a 150-200%
> performance gain, but it still takes far too long.... ;-)
Received on Thu Mar 12 1998 - 00:00:00 CST

Original text of this message

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