Logical IO Current Mode for MV Refresh

Question

Guys,
I am seeing a materialized view refresh output in tkprof which is showing a large number of current mode reads (about 4x the consistent gets).
There is an index on the materialized view. TKPROF does not show a DELETE for the materialized view.
What would cause current mode reads on an INSERT for this type of MV refresh?
Thanks in advance.

Answer 1

Matt T wrote:
I am seeing a materialized view refresh output in tkprof which is showing a large number of current mode reads (about 4x the consistent gets).
There is an index on the materialized view. TKPROF does not show a DELETE for the materialized view.
What would cause current mode reads on an INSERT for this type of MV refresh?We could do with more detail about the nature of the refresh and the version of Oracle. But if you're looking at something which is basically a simple insert then it's not too surprising given you've got an index on the materialized view. Very approximately, the number of CR gets will be in the region of the number of blocks you change, and the number of CU gets will (thanks to the index) be in the region of the number of rows you insert.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk
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