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Re: What is different between sql*load(direct=y) and insert /+*append */

From: M Hashim <m.a.n.hashim_at_sympatico.ca>
Date: Wed, 2 Oct 2002 00:09:09 -0700
Message-ID: <vhum9.5422$Kg4.867444@news20.bellglobal.com>


clickstream data....yikes!

Note also, with "direct load" I don't think you could manipulate the data with any FUNCTIONS as it's being loaded - which you can do otherwise.

"Howard J. Rogers" <howardjr2000_at_yahoo.com.au> wrote in message news:Q3nm9.44168$g9.126416_at_newsfeeds.bigpond.com...
> Both tools load data into tables above the high watermark, and only move
the
> high watermark above the 'data line' at the end of the operation (when you
> commit or SQL Loader does a data save). Since data is above the high
> watermark for the duration of the load, using either tool, it is
impossible
> to read that data (that's what the HWM's job is, after all: telling full
> table scans when to stop looking for data).
>
> If it's impossible to read the data, then there is no need for either tool
> to generate rollback, which is (putting it simply) only needed for the
> purposes of constructing read-consistent images of the data *for other
> Users' benefit*. They can't see the data, therefore they don't need
> read-consistent images of it, therefore no rollback.
>
> So far, so similar.
>
> The difference between the two tools is what happens on indexes. SQL
Loader
> Direct Loads don't update indexes. Append inserts do. Which means that
> insert appends are required to generate rollback on the indexes, because
the
> changes it makes to them during the insert operation *are* visible to
other
> users, and hence they need to roll them back for read-consistency
purposes.
>
> Regards
> HJR
>
> "David" <dhs_69_at_hotmail.com> wrote in message
> news:7e64a3ea.0210011044.706e0261_at_posting.google.com...
> > Hi,
> >
> > We used to use sql*load with direct=y option to load
> > our clickstream data,in order to get better performance,
> > we recently use " insert /+* append */ "
> > approach, but we got "rollback segment too small" error.
> >
> > how sql*load never got this problem ? what is the different
> > between two approachs in oracle?
> >
> > Thanks
> > David
>
>
Received on Wed Oct 02 2002 - 02:09:09 CDT

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