Re: Row Migration

This is a single process executing PDML - As you guessed, the problem arises where an update causes a migration into the top block on the free list - every PX slave is updating a different range, but they might all migrate into the same free block.

Except --
a) Oracle handles this differently on PDML updates to partitioned tables with global indexes: the degree of parallelism in this case is limited to the smallest value for INITRANS found on any of the global indexes.

b) If a migration is treated as an insert, then for normal inserts, an absence of freelists results in the next block on the freelist being used anyway.

So I can't see why Oracle Corp. has done it this way. (I'm not going to worry about it though, at least for the next couple of weeks - and I'm going to see Steve in Denmark soon, and he may have all the answers by then).

Regards

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

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____England______January 21/23

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

-----Original Message-----
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Date: 29 December 2002 15:45

>
>Are you talking about a single process using parallel DML? I guess I
could
>imagine that even in a case such as a single parallel update setting
a
>column to a constant. Even though the parallelism would have broken
things
>up by block ranges, migration could occur into the same block for
multiple
>processes.
>

-- 
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Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

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