Re: Bug with CAST and parallelism?

Herring Dave - dherri wrote:

> Database is Oracle 9.2.0.6, OS is Tru64 5.1, data warehouse environment.
>
> It appears that when using the CAST function with a SUBSTR, against data
> from a table that has parallelism set, Oracle "pre-processes" the data
> using the CAST function. I can explain this best with an example
> (unfortunately based on a production job)
[...]
>
> Not only did the column with the CAST(SUBSR... functions on it get
> converted to VARCHAR2(6) BEFORE the functions were run, but so did the
> second column with no functions applied to it.
>
> I'll file this as a bug with Oracle, but I'm curious if anyone has run
> into anything similar to this before or can reproduce this on different
> versions of Oracle.
>
> The workaround is simple enough: remove parallelism or use NOPARALLEL(a)
> hint. Unfortunately, being a DW the tables are rather large (although
> correct data wins over fast data). Those who wrote refresh of various
> tables always recreate the tables using CTAS, so the CAST function is
> found in a lot of code. Sure would stink if this problem is happening
> elsewhere and we have yet to discover it!
>

There was a similar discussion about a year ago in c.d.o.misc.

http://tinyurl.com/fole6

If you sift through the tangential comments, the conclusion seemed to be that there was indeed a bug, or at least severely mis-documented behavior, with the CAST function.

-- 
Mark Bole
http://www.bincomputing.com



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