I read APARs so you don’t have to.. pretty weird, right? This strange habit actually started back in 1978 just after the bank I worked for started to use SMP/E. I discovered that I could read the covers of the APARs to learn lots of inside stuff about how IMS worked. For some reason, I never completely got over this strange habit. I still find this stuff of interest although APAR covers don’t carry anywhere near the information they used to……
Of course, all of that is way to random and a complete tangent from what the intent of today’s post is supposed to be about.
Now, getting back to the subject on hand….
Today’s post is about something new added to DB2. However, in this case the word “new” being relative, it’s about something that was actually added back in December 2010.
DNS6SPRM, one of the DSNZPARM macros, has a new keyword: CHECK_FASTREPLICATION. This has to do with how the SHRLEVEL CHANGE CHECK utility invoking DSS COPY uses the COPY command’s FASTREPLICATION keyword to determine what type of replication DSS COPY uses..
The ZPARM takes two values: REQUIRED and DEFERRED.
REQUIRED forces the CHECK utility to use DSS COPY. If Flash Copy cannot be used, the CHECK utility fails. This is the default setting in DB2 10.
PREFERRED simply directs the CHECK utility to use fast replication only if Flash Copy is available. This is the default setting for DB2 9.
There is a subtle difference between the two values for this keyword. DEFERRED will use Flash Copy V2 if it is available. While REQUIRED will cause the utility to fail if Flash Copy V2 is not available. In almost all cases you do WANT to use REQUIRED to minimize the outage that could be incurred by CHECK taking a long time to copy objects. The indexes and data are in READ-ONLY while being copied. .
All of this new CHECK utility DSNZPARM stuff is discussed in the “DB2 10 Installation and Migration Guide” (GC19-2974) and the “DB2 9 Installation Guide” (GC18-9846), both recently refreshed in December 2010. It was also introduced via an APAR in December. Good timing on the part of the publication folk don’t you think?
In DB2 9, CHECK_FASTREPLICATION keyword is only modifiable by editing your ZPARMs directly. However, in DB2 10 this field is included on the installation panel DSNTIP6 as the FAST REPLICATION field.
You can find the APAR at:
APAR PM19034 closed back on December 16, 2010. It’s listed as a DB2 9 APAR although it results in PTFs for not only DB2 9 (UK62437), but also DB2 10 (UK63215) and DB2 Version 8 (UK63216). DB2 Version 8 is only affected because the APAR updates DSNADMIZ, the external module for SYSPROC.ADMIN_INFO_SYSPARM stored procedure. In order to support data sharing coexistence, the Version 8 flavor of SYSPROC.ADMIN_INFO_SYSPARM must be able to recognize the new ZPARM.
If SYSPROC.ADMIN_INFO_SYSPARM is of interest to you, you can read more about setting it and its outputs in Appendex B of the DB2 9 (SC18-9840) and DB2 10 (SC19-2968) Adminstration Guides.
You can download the latest editions of the DB2 9 and DB2 10 Installation Guides and Adminstration Guides at the DB2 for z/OS Technical Resource page or view them on the web at DB2 for z/OS Information Center.
When researching information in the product documentation, remember that the DB2 for z/OS Information Center will almost always have the most up-to-date product information in it.
Finally, I do realize it’s not Friday… (smile)…