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Re: Why the difference?

From: Jon Waterhouse <jonwaterhouse_at_mail.gov.nf.ca>
Date: Wed, 3 Apr 2002 15:40:13 -0330
Message-ID: <3cab531e.0@209.128.1.3>


Thanks,

NOLOGGING on the table should help a bit. I'm still exploring to try and find where the _big_ difference comes from. It's not just from that.

Thanks,

Jon

"ZV" <valliz_at_consultant.com> wrote in message news:3CAA218E.C6D8377_at_consultant.com...
> Try to create your "extractmonth" table first, but using the NOLOGGING
> option (same option for the indexes, if any)... I think this option
> prevents the database from making any copy of the table in case of a
> rollback (which takes a long time). But, note using this option, you
> will not be able to rollback.
>
> Jon Waterhouse wrote:
> >
> > I have a file with about 800,000 records from which I need to extract
> > one month's worth of data (about 30,000) records.
> >
> > insert column_names into extractmonth
> > (select column_names from fullfile where year = 1999 and month = 4);
> >
> > runs at about 2.5 hours.
> >
> > create table extractmonth as
> > select column_names from fullfile where year = 1999 and month = 4;
> >
> > runs at about 2.5 seconds.
> >
> > There is an index on year and month on full file.
> >
> > Any ideas on what causes the difference?
Received on Wed Apr 03 2002 - 13:10:13 CST

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