SV: [DB2-L] Quiesce Write Yes or No?

Olle Brostrom

SV: [DB2-L] Quiesce Write Yes or No?
If you are on DB2 9 you can skip your QUIESCE.
DB2 9 will automatically backout any ongoing UOR for the selected recovery point so there are no need to execute QUIESCE to get recovery points any more.
If you are on a lower version of DB2 you can also skip your QUIESCE if you have a Log Analyzer Tool, such a tool can report RBA/LRSN ranges where there are no UOR's active for a specific object.
The difference between QUIESCE WRITE YES and WRITE NO is that the latter one does not write the updated pages in the bufferpol to the tablespace, both variations of QUIESCE will drain writers to get the QUIESCE point to be inserted in SYSCOPY. I don't think WRITE NO is less disruptive?

Olle

Från: IDUG DB2-L [mailto:[login to unmask email] För Jose de Bedos
Skickat: den 3 februari 2011 19:07
Till: [login to unmask email]
Ämne: [DB2-L] Quiesce Write Yes or No?


Hi List,

after every COPY with SHRLEVEL CHANGE, we execute a QUIESCE WRITE YES.
Ocasionally we have an abend because the process couldn't drain an index.
As we don't have indexes with COPY YES, is it safe to change to WRITE NO?
I think the answer is NO, but want to be sure.
I've seen a presentation where it says it's less disruptive. But says nothing about if it's safe to do it that way, at least in this case.

Have a good time,
Jose


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Christian Michel

Re: SV: [DB2-L] Quiesce Write Yes or No?
(in response to Olle Brostrom)
Let me chime on on this question, since I think I know in which
presentation you saw this comment (Utilities Best Practices):

QUIESCE WRITE NO will only drain COPY YES indexes, while WRITE YES will
drain all indexes. So there is a different impact of using WRITE YES/NO.
We recommend WRITE YES only if you're using DSN1COPY as well that needs
all pages to be forced out to disk "now". Otherwise WRITE NO will not
force out the pages immediately but simply let the check point care of
this. This will have a short delay until the pages are written out, but
the exposure should not be that great, unless you're not checkpointing on
a regular basis.

Olle is right about the hint that the necessity to run QUIESCE should be
reduced significantly once you're on DB2 9 NFM, as we will back out all
uncommitted work during a PIT recovery.

Mit freundlichen Grüßen / Kind regards
Christian Michel

Christian Michel
E-mail: [login to unmask email]
Phone (49)-7031-16-4293
DB2 for z/OS Utilities Development
Information Management Development Boeblingen, Germany



IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martin Jetter
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart,
HRB 243294



From: Olle Brostrom <[login to unmask email]>
To: [login to unmask email]
Date: 02/04/2011 08:05 AM
Subject: [DB2-L] SV: [DB2-L] Quiesce Write Yes or No?
Sent by: IDUG DB2-L <[login to unmask email]>



If you are on DB2 9 you can skip your QUIESCE.
DB2 9 will automatically backout any ongoing UOR for the selected recovery
point so there are no need to execute QUIESCE to get recovery points any
more.
If you are on a lower version of DB2 you can also skip your QUIESCE if you
have a Log Analyzer Tool, such a tool can report RBA/LRSN ranges where
there are no UOR?s active for a specific object.
The difference between QUIESCE WRITE YES and WRITE NO is that the latter
one does not write the updated pages in the bufferpol to the tablespace,
both variations of QUIESCE will drain writers to get the QUIESCE point to
be inserted in SYSCOPY. I don?t think WRITE NO is less disruptive?

Olle

Från: IDUG DB2-L [mailto:[login to unmask email] För Jose de Bedos
Skickat: den 3 februari 2011 19:07
Till: [login to unmask email]
Ämne: [DB2-L] Quiesce Write Yes or No?


Hi List,

after every COPY with SHRLEVEL CHANGE, we execute a QUIESCE WRITE YES.
Ocasionally we have an abend because the process couldn't drain an index.
As we don't have indexes with COPY YES, is it safe to change to WRITE NO?
I think the answer is NO, but want to be sure.
I've seen a presentation where it says it's less disruptive. But says
nothing about if it's safe to do it that way, at least in this case.

Have a good time,
Jose




The IDUG DB2-L Listserv is only part of your membership in IDUG. If you
are not already an IDUG member, please register here.

_____________________________________________________________________
* IDUG North America * Anaheim, California * May 2-6 2011 * http://IDUG.ORG/NA *
* If you are going to attend only one conference this year, this is it! *
_____________________________________________________________________
http://www.IDUG.org/mentor
Mentoring should be a rewarding experience for everyone...
IDUG is offering up to 80% off when you both come to the conference!
_____________________________________________________________________

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Raymond Bell

Re: SV: [DB2-L] Quiesce Write Yes or No?
(in response to Christian Michel)
'...we will back out all uncommitted work during a PIT recovery...'

Yawn. Some recovery products have been able to do that for years, regardless of DB2 version. ;o)

Notice I didn't say which one? Does that mean I escape the VendorPolizei? ;o)

Cheers,


Raymond


From: IDUG DB2-L [mailto:[login to unmask email] On Behalf Of Christian Michel
Sent: 04 February 2011 12:22
To: [login to unmask email]
Subject: Re: [DB2-L] SV: [DB2-L] Quiesce Write Yes or No?

Let me chime on on this question, since I think I know in which presentation you saw this comment (Utilities Best Practices):

QUIESCE WRITE NO will only drain COPY YES indexes, while WRITE YES will drain all indexes. So there is a different impact of using WRITE YES/NO. We recommend WRITE YES only if you're using DSN1COPY as well that needs all pages to be forced out to disk "now". Otherwise WRITE NO will not force out the pages immediately but simply let the check point care of this. This will have a short delay until the pages are written out, but the exposure should not be that great, unless you're not checkpointing on a regular basis.

Olle is right about the hint that the necessity to run QUIESCE should be reduced significantly once you're on DB2 9 NFM, as we will back out all uncommitted work during a PIT recovery.

Mit freundlichen Grüßen / Kind regards
Christian Michel
Christian Michel

E-mail: [login to unmask email]

Phone (49)-7031-16-4293

DB2 for z/OS Utilities Development

Information Management Development Boeblingen, Germany





IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martin Jetter
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294



_____________________________________________________________________
* IDUG North America * Anaheim, California * May 2-6 2011 * http://IDUG.ORG/NA *
* If you are going to attend only one conference this year, this is it! *
_____________________________________________________________________
http://www.IDUG.org/mentor
Mentoring should be a rewarding experience for everyone...
IDUG is offering up to 80% off when you both come to the conference!
_____________________________________________________________________

If you need to change settings, http://www.idug.org/cgi-bin/wa?A0=DB2-L is the home of IDUG's Listserv

Roy Boxwell

Re: SV: [DB2-L] Quiesce Write Yes or No?
(in response to Raymond Bell)
neeee naaaa neeee naaaa ...Hello, Hello, Hello evenin' all ! Gotcha Mr
Bell !

Roy Boxwell
SOFTWARE ENGINEERING GMBH
-Product Development-
Robert-Stolz-Straße 5
40470 Düsseldorf/Germany
Tel. +49 (0)211 96149-675
Fax +49 (0)211 96149-32
Email: [login to unmask email]
http://www.seg.de

Software Engineering GmbH
Amtsgericht Düsseldorf, HRB 37894
Geschäftsführung: Gerhard Schubert



"Bell, Raymond" <[login to unmask email]>
Gesendet von: IDUG DB2-L <[login to unmask email]>
04.02.2011 13:31
Bitte antworten an
IDUG DB2-L <[login to unmask email]>


An
[login to unmask email]
Kopie

Thema
Re: [DB2-L] SV: [DB2-L] Quiesce Write Yes or No?






’...we will back out all uncommitted work during a PIT recovery...’

Yawn. Some recovery products have been able to do that for years,
regardless of DB2 version. ;o)

Notice I didn’t say which one? Does that mean I escape the VendorPolizei?
;o)

Cheers,


Raymond


From: IDUG DB2-L [mailto:[login to unmask email] On Behalf Of Christian
Michel
Sent: 04 February 2011 12:22
To: [login to unmask email]
Subject: Re: [DB2-L] SV: [DB2-L] Quiesce Write Yes or No?

Let me chime on on this question, since I think I know in which
presentation you saw this comment (Utilities Best Practices):

QUIESCE WRITE NO will only drain COPY YES indexes, while WRITE YES will
drain all indexes. So there is a different impact of using WRITE YES/NO.
We recommend WRITE YES only if you're using DSN1COPY as well that needs
all pages to be forced out to disk "now". Otherwise WRITE NO will not
force out the pages immediately but simply let the check point care of
this. This will have a short delay until the pages are written out, but
the exposure should not be that great, unless you're not checkpointing on
a regular basis.

Olle is right about the hint that the necessity to run QUIESCE should be
reduced significantly once you're on DB2 9 NFM, as we will back out all
uncommitted work during a PIT recovery.

Mit freundlichen Grüßen / Kind regards
Christian Michel

Christian Michel
E-mail: [login to unmask email]
Phone (49)-7031-16-4293
DB2 for z/OS Utilities Development
Information Management Development Boeblingen, Germany



IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martin Jetter
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart,
HRB 243294





The IDUG DB2-L Listserv is only part of your membership in IDUG. If you
are not already an IDUG member, please register here.


_____________________________________________________________________
* IDUG North America * Anaheim, California * May 2-6 2011 * http://IDUG.ORG/NA *
* If you are going to attend only one conference this year, this is it! *
_____________________________________________________________________
http://www.IDUG.org/mentor
Mentoring should be a rewarding experience for everyone...
IDUG is offering up to 80% off when you both come to the conference!
_____________________________________________________________________

If you need to change settings, http://www.idug.org/cgi-bin/wa?A0=DB2-L is the home of IDUG's Listserv

Raymond Bell

Re: SV: [DB2-L] Quiesce Write Yes or No?
(in response to Roy Boxwell)
Is that my collar wot’s just been felt? Guess it’s a fair cop, guv’... ;o)


From: IDUG DB2-L [mailto:[login to unmask email] On Behalf Of Roy Boxwell
Sent: 04 February 2011 12:37
To: [login to unmask email]
Subject: Re: [DB2-L] SV: [DB2-L] Quiesce Write Yes or No?


neeee naaaa neeee naaaa ...Hello, Hello, Hello evenin' all ! Gotcha Mr Bell !

Roy Boxwell
SOFTWARE ENGINEERING GMBH
-Product Development-
Robert-Stolz-Straße 5
40470 Düsseldorf/Germany
Tel. +49 (0)211 96149-675
Fax +49 (0)211 96149-32
Email: [login to unmask email]
http://www.seg.de

Software Engineering GmbH
Amtsgericht Düsseldorf, HRB 37894
Geschäftsführung: Gerhard Schubert

"Bell, Raymond" <[login to unmask email]>
Gesendet von: IDUG DB2-L <[login to unmask email]>

04.02.2011 13:31
Bitte antworten an
IDUG DB2-L <[login to unmask email]>


An

[login to unmask email]

Kopie

Thema

Re: [DB2-L] SV: [DB2-L] Quiesce Write Yes or No?







’...we will back out all uncommitted work during a PIT recovery...’

Yawn. Some recovery products have been able to do that for years, regardless of DB2 version. ;o)

Notice I didn’t say which one? Does that mean I escape the VendorPolizei? ;o)

Cheers,


Raymond


From: IDUG DB2-L [mailto:[login to unmask email] On Behalf Of Christian Michel
Sent: 04 February 2011 12:22
To: [login to unmask email]
Subject: Re: [DB2-L] SV: [DB2-L] Quiesce Write Yes or No?

Let me chime on on this question, since I think I know in which presentation you saw this comment (Utilities Best Practices):

QUIESCE WRITE NO will only drain COPY YES indexes, while WRITE YES will drain all indexes. So there is a different impact of using WRITE YES/NO. We recommend WRITE YES only if you're using DSN1COPY as well that needs all pages to be forced out to disk "now". Otherwise WRITE NO will not force out the pages immediately but simply let the check point care of this. This will have a short delay until the pages are written out, but the exposure should not be that great, unless you're not checkpointing on a regular basis.

Olle is right about the hint that the necessity to run QUIESCE should be reduced significantly once you're on DB2 9 NFM, as we will back out all uncommitted work during a PIT recovery.

Mit freundlichen Grüßen / Kind regards
Christian Michel
Christian Michel

E-mail: [login to unmask email]

Phone (49)-7031-16-4293

DB2 for z/OS Utilities Development

Information Management Development Boeblingen, Germany





IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martin Jetter
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294



________________________________

The IDUG DB2-L Listserv is only part of your membership in IDUG. If you are not already an IDUG member, please register here. < http://www.idug.org/register >



________________________________

[ http://www.idug.org/images/stories/db2/db2_10_savings.jpg ] < http://www-01.ibm.com/software/data/db2/zos/db2-10/ >

The IDUG DB2-L Listserv is only part of your membership in IDUG. If you are not already an IDUG member, please register here. < http://www.idug.org/register >

_____________________________________________________________________
* IDUG North America * Anaheim, California * May 2-6 2011 * http://IDUG.ORG/NA *
* If you are going to attend only one conference this year, this is it! *
_____________________________________________________________________
http://www.IDUG.org/mentor
Mentoring should be a rewarding experience for everyone...
IDUG is offering up to 80% off when you both come to the conference!
_____________________________________________________________________

If you need to change settings, http://www.idug.org/cgi-bin/wa?A0=DB2-L is the home of IDUG's Listserv

Max Scarpa

Re: SV: [DB2-L] Quiesce Write Yes or No?
(in response to Raymond Bell)
Hi All

WRITE NO is usually a good choiche for most activities. Years ago we used
WRITE YES to flush (as said before) page to DASDs (now to DASD cache) to
be sure data pages were on disk (for instance for backups using DFSMSdss
or DSN1COPY or it was used 'under the cover' by 3rd party 'fast'
utilities to be sure you were copying all data pages).
Since then I used WRITE NO mainly as DB2 utilities take care of it and
because, due to restricted compatibility matrix, some QUIESCE took too
long to be executed (we had abend has well because long running batch
jobs, mainly) or caused other jobs to abend. Now in V9 there are less
reasons to use QUIESCE YES.

Max Scarpa

DB2 pole position rule: The early prod user catches the bug.





_____________________________________________________________________
* IDUG North America * Anaheim, California * May 2-6 2011 * http://IDUG.ORG/NA *
* If you are going to attend only one conference this year, this is it! *
_____________________________________________________________________
http://www.IDUG.org/mentor
Mentoring should be a rewarding experience for everyone...
IDUG is offering up to 80% off when you both come to the conference!
_____________________________________________________________________

If you need to change settings, http://www.idug.org/cgi-bin/wa?A0=DB2-L is the home of IDUG's Listserv