Using FASTSWITCH YES in Online Reorgs

Duane Goertz

Using FASTSWITCH YES in Online Reorgs


Is there any reason not to use FASTSWITCH YES in an online reorg (but
rather to opt for FASTSWITCH NO which causes the SWITCH phase to use
IDCAMS RENAME)? I realize FASTSWITCH YES is faster but are there
situations where its use isn't advisable or where it can cause problems?
We currently use FASTSWITCH NO and I'm trying to determine if there's
any reason not to change to FASTSWITCH YES. We are using DB2 for z/OS
version 7.1









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Michael Ebert

Re: Using FASTSWITCH YES in Online Reorgs
(in response to Duane Goertz)
With FASTSWITCH YES, you have a mixture of *.I0001.* and *.J0001.* VSAM
dataset names. You have to take that into account if you access VSAM files
directly, e.g. if you use DSN1COPY to populate a test database.

Also a DS list of a partitioned object won't be sorted in an orderly
manner (by partition) if you've got a mixture of I and J datasets from
running partition-level OLR.

Generally FASTSWITCH YES is most useful if you run OLR on TSs with many
VSAM files, i.e. partitioned tables with many partitions, TSs with many
indexes (e.g. XSAP tables) or non-partitioned TSs with many datasets (for
an individual definition of "many").

Dr. Michael Ebert
DB2 & Oracle Database Administrator
aMaDEUS Data Processing
Erding / Munich, Germany








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[DB2-L] Using FASTSWITCH YES in Online Reorgs







Is there any reason not to use FASTSWITCH YES in an online reorg (but
rather to opt for FASTSWITCH NO which causes the SWITCH phase to use
IDCAMS RENAME)? I realize FASTSWITCH YES is faster but are there
situations where its use isn?t advisable or where it can cause problems?
We currently use FASTSWITCH NO and I?m trying to determine if there?s any
reason not to change to FASTSWITCH YES. We are using DB2 for z/OS
version 7.1

---------------------------------------------------------------------------------
Welcome to the IDUG DB2-L list. To unsubscribe, go to the archives and home page at http://www.idugdb2-l.org/archives/db2-l.html. From that page select "Join or Leave the list". The IDUG DB2-L FAQ is at http://www.idugdb2-l.org. The IDUG List Admins can be reached at [login to unmask email] Find out the latest on IDUG conferences at http://conferences.idug.org/index.cfm