Need info on QUIESCE utility in DB2

subratarec · Posted: Fri May 22, 2015 12:30 pm

Hi,

I need one small info on QUIESCE utility. One of my project mate came to me and asked that in his LOAD JCL he can see one step called QUIESCE but he can't see any step named UNQUIESCE through which it restores user access to instances or databases which have been quiesced.

So I know how QUIESCE utility works but I also haven't seen any explicit UNQUIESCE step against that QUIESCE utility.

So my query is do we really need to have explicit UNQUIESCE step for each QUIESCE step or is it like, the moment QUIESCE JCL complete it's work successfully DB2 automatically releases all the locks QUIESCE had held on?

mjadwani2785 · Posted: Mon May 25, 2015 4:24 am

Hi ,

Quiesce is used to establish quiesce point which can be usedas point of consistency during recovery . This quiesce point which is RBA / LRSN is written in SYSCOPY catalog table as TYPE 'Q'.

There is no thing called UNQUIESCE on DB2 for z/OS.

"Though there is db2 command SET LOG SUSPEND and SET LOG RESUME which does similar type of work but at DB2 level not at tablespace level. "

Locks are released when The QUIESCE steps complete i.e to say TS are back in RW mode once it completes.

For concurrency and compatibility of QUIESCE utility refer DB2 Utility guide .

Hope this helps !!

Regards,
MJ

subratarec · Posted: Mon May 25, 2015 12:19 pm

Hi mjadwani2785,

Thanks for your reply. What I have found is there is a command called "UNQUIESCE" available for DB2 LUW and DBA uses them frequently to release the DB2 resource just after successful QUIESCE. So by reading this a question came into my mind why we don't use that command for DB2 for Z/OS.

Does that mean DB2 for Z/OS automatically takes care of that post successful execution of QUIESCE point job which not available for DB2 LUW and thats the reason DB2 LUW has specific "UNQUIESCE" command?

UNQUIESCE link --> http://www-01.ibm.com/support/knowledgecenter/SSEPGG_10.5.0/com.ibm.db2.luw.admin.cmd.doc/doc/r0008636.html?cp=SSEPGG_10.5.0%2F3-6-2-4-135

Thanks
Subrata

mjadwani2785 · Posted: Mon May 25, 2015 3:04 pm

Hi ,

I read the link you shared . As I mentioned earlier there is no thing called Unquiesce command on DB2 for z/OS. Quiesce Utility once complete puts the TS into normal mode.
I think you are comparing Commands with Utility.

Now speaking of QUIESCE and UNQUIESCE command on DB2 LUW , what I have understood is

QUIESCE db corresponds to START DB(dbname) access(mode) command on mainframe.
QUIESCE instance corresponds to START DB2 access(maint) mode on mainframe.

UNQUIESCE db corresponds to START DB(dbname) in normal mode.
UNQUIESCE instance is START DB2 in normal mode.

These are used to do some administrative task over database or instance which requires no user to be holding any of the db2 resource other then the administrator of the activity .

There is also QUIESCE TABLESPACE for TABLE command on LUW which can correspond to
START DB(dbname) sp(tsname) access(mode) on mainframe depending on the type of use i.e concurrency required.

Well this command (LUW one) as the manuals says can be used during the LOAD duration . Once load is complete exclusive reset is required.

Well after reading both, Quiesce command on DB2 LUW and Quiesce Utility on Mainframe both have different purpose on different system , where one is used to put your DB2 object in some kind of restrictive mode (LUW) and on mainframe purpose is to establish point of consistency.

Its just my interpretation of DB2 LUW and DB2 z/OS analogy . I am no expert .

Regards,
MJ

subratarec · Posted: Mon May 25, 2015 8:38 pm

Hi mjadwani2785,

Thanks for your comment. Yep after going few more articles I think what u wrote is right.

Thanks
Subrata