Comments on: Wide Table Select ( Row Shipping )

By: oraclue

oraclue — Tue, 13 Oct 2009 13:52:28 +0000

Hi Tim,

Thanks for reading my post.
I saw your post.Very good example.As you know Oracle is not documenting all features and sometime is hard to find out what is really going on.

Thanks,

Miladin

By: Tim Hopkins

Tim Hopkins — Mon, 05 Oct 2009 13:27:57 +0000

I failed trying to post the sample code here so I’ve posted it to my nascent blog instead.

Please see the url below for a demonstration of the problem with virtual columns and row shipping in 11.1.0.6
http://timothyhopkins.net/?p=18

Cheers,
Tim

By: Tim Hopkins

Tim Hopkins — Mon, 05 Oct 2009 12:53:12 +0000

Thanks Miladin, this helped to give us a bit more insight into a problem we were having with virtual columns on 11.1.0.6.

We have a scenario where virtual columns were being returned as NULL if we used SELECT * and the table contained above a certain number of columns.
After stumbling across your post, I now realise it’s because virtual columns don’t seem to be compatible with this row shipping ‘enhancement’.

I’ll try posting some sample test case code in another comment. Fingers crossed WordPress doesn’t screw up the formatting.

By: oraclue

oraclue — Fri, 17 Jul 2009 18:03:50 +0000

Hi Frits,

Please see last post Direct path reads and serial table scans in 11g.

Thanks for reading my blog.

Miladin

By: Frits Hoogland

Frits Hoogland — Fri, 17 Jul 2009 17:33:50 +0000

Doug burns observed full table scans which resulted in ‘direct path reads’ instead of the ‘db file scattered reads’ you would expect in Oracle 11. Could this be related?