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Hi Charles

In at least one case dealing with a table of 150+ million rows I gained
significant advantage by deleting the logicals and recreating them after my
processing was done. (At least I think I gained an advantage - I may have a
different view after posting this)

In this case the logicals had been created as determined by development
requirements (i.e. relatively randomly :) ) which provided an opportunity to
re-create the logicals in a sequence that took advantage of access path
sharing to save space, but more importantly to improve the speed of
recreating the subsequent access paths (and probably maintenance as well).

I tried to order the creation of the logicals in such a way as to allow
creation of a new logical to leverage already existing access paths by doing
some analysis on the keys of the logicals - essentially I created from most
complex to least complex; there may have been better ways to do it. I also
dual streamed the creation process so that I had two logicals being created
concurrently and had similar key structures in the same job path.

Maybe I needn't have actually done re-created the logicals - I don't know if
just removing and adding the member would have the same effect, but some
testing might shed some light on it.

Regards
Evan Harris


On Wed, Jun 30, 2010 at 3:30 AM, Charles Wilt <charles.wilt@xxxxxxxxx>wrote:

Before I start rolling my own, is anybody aware of a utility to remove
all members from dependent logical files (and SQL views/indexes) for a
given physical that will allow for the members to be automatically
re-added later?

My intent it to purge data from files on our development machine.

remove logical file members
(optionally) stop journalling
delete records from physical
reorg physical
(optionally) restart journalling
re-add logical file members


I'm thinking that at least the logical file member portion may also be
useful in a bulk data load process..




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