RE: External tables

True, but IIRC where external tables really outshine SQL*Loader is where you may not need to actually load the data. As an example, one client I saw using external tables received an hourly feed from an external source. They had some code written to check if the file arrived, load it if it had and so on. With external tables the data is only read if it's needed. The client I'm referring to simply kept the same file name each time, and the overhead of loading the material went down from occurring every hour to occurring only when the table was queried. Of course, there's the issue that the overhead of the load now occurred at the time of the query, but for this particular customer that wasn't so much of a concern.

Pete
"Controlling developers is like herding cats." Kevin Loney, Oracle DBA Handbook
"Oh no, it's not. It's much harder than that!" Bruce Pihlamae, long-term Oracle DBA  

-----Original Message-----
Sent: Thursday, April 24, 2003 3:02 PM
To: Multiple recipients of list ORACLE-L

Another point missed so far is that
if your SQL to the external table hits
some dirty data, then it bombs out
with an Oracle error, and if you've been busy running an insert from it the next
thing that happens is a likely to be a
massive rollback.

You also have to deal with the discard/bad file (in the event that your external table definition includes a 'bad limit' and doesn't crash your process) so you haven't really got rid of much of the infrastructure that you would need if you were to use sqlldr - only the SQLLOAD command and a
couple of lines of shell to check the exit status from SQLLOAD and grep/awk the
rows-loaded count from the log.

Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

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• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: 24 April 2003 19:16

> The replies so far have failed to mention that parallel loading with
> external tables is easy. With sqlloader, it ain't so easy.
>
> With external tables, it is also easy to do additional processing
via
> SQL when you load. In many cases you could avoid extra steps
required
> in sqlloader, such as loading to a temp table, then massaging your
data
> and loading to a perm table.
>
> You can skip the temp table with external tables.
>
> Jared
>
>
>

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