Guys, there are some discrepancies in the mails below:
T.Rob writes: ... never hits the disk ... Gregg writes: ... without ever "going on the queue" ... As far as I know, persistent messages are always written to the log, but not always to the queue. The documents of the MQ course MQ15 (WebSphere MQ Systems Administration I for Distributed Platforms) I found the text "... persistent message are written out to a log ..." (I miss the word "always" in this document). In the system administration guide (distributed) I found the sentence "WebSphere MQ records all significant changes to the data controlled by the queue manager in a recovery log.". The documents of the MQ course MQ20 (WebSphere MQ for z/OS System Administration)the description is similar (All message ... activity ... is done within pages of the WebSphere MQ for z/OS buffer pools. At the same time, changes to recoverable (persistent) messages are written to log records ...) (again, I miss the word "always" in this document). So I am very interested in T.Robs presentation. Regards Hubert > -----Ursprüngliche Nachricht----- > Von: MQSeries List <[email protected]> > Gesendet: 06.12.06 00:18:51 > An: [email protected] > Betreff: Re: UOW, Persistence, Reliabiltiy > I also remember this being mentioned in a > presentation. I thought it had something to do with a > performance report that made WMQ look bad. WMQ didn't > perform very well in an environment of persistent > messages outside of a unit of work (it was also > questioned why you would do this). The solution was > to deliver the message to the getter immediately since > they were already waiting. > > Ron > > --- "Tuben, Gregg" <[EMAIL PROTECTED]> wrote: > > > That is how I understand it as well - this is > > relatively new on z/OS > > but, has been around that way on distributed for a > > long time (5.2 I > > think). If there is a waiting getter the > > non-persistent message is > > delivered directly to the app without ever "going on > > the queue" > > Gregg > > > > -----Original Message----- > > From: MQSeries List > > [mailto:[EMAIL PROTECTED] On > > Behalf Of T-Rob > > Sent: Tuesday, December 05, 2006 3:27 PM > > To: [email protected] > > Subject: Re: UOW, Persistence, Reliabiltiy > > > > Roger, > > > > That info was based on a WMQ internals class I > > attended at the last > > conference. I may have that presentation at home > > and will look for it > > this weekend. But the gist of it was that a message > > outside of > > syncpoint > > has no recovery after it is handed off to a > > receiving app. So if an app > > > > has a handle open on a queue at the moment an > > eligible persistent > > message > > arrives, the message is transferred in memory and > > never hits the disk. > > > > -- T.Rob > > > > T.Robert Wyatt, Consulting IT Specialist > > IBM Software Services for Websphere > > email: [EMAIL PROTECTED] > > 704-719-2107 Access Line > > > > > > > > > > Roger Lacroix <[EMAIL PROTECTED]> > > Sent by: MQSeries List > > <[email protected]> > > 12/05/2006 01:25 PM > > Please respond to > > MQSeries List <[email protected]> > > > > > > To > > [email protected] > > cc > > > > Subject > > Re: UOW, Persistence, Reliabiltiy > > > > > > > > > > > > > > Hi, > > > > > in another discussion i just learned that putting > > a persistent message > > > > out > > > of sync is not written to log if there is an > > open/read handle on that > > > queue. this was the beginning of my confusion. > > > > False. All persistent messages are written to the > > log. > > > > > > > so if messages are non-persistent the log only > > contains transaction > > > information. this information can be used as trace > > information. but > > not > > > for recovering? > > > > False. The log will contain both persistent messages > > and transactional > > information. > > > > > > > if messages are declared as persistent but > > applications are never > > > processing the messages within transactions, the > > log just contains the > > > message. a manually recovering is theoretical > > possible? > > > > True not theoretical but practical. Go read chapter > > 14 of the WMQ > > System > > Administration Guide. > > > > > > > if messages are persistent and applications > > process the messages > > within > > > unit of works, mq can do his work and recover. > > > > True. > > > > > > > if the application crashes while getting a message > > out of sync, the > > > message is lost. independant if it is persistent > > or non-persistent. is > > > > By 'application crashes' then I presume that the > > queue manager did not > > crash, hence the answer is one of 3: > > > > 1) If the MQPUT returned cc=0 and rc=0 then the > > application crashes, MQ > > has the message and it is not lost. > > > > 2) If the MQPUT returned cc=1/2 and rc!=0 then the > > application crashes, > > MQ > > does not have the message and the reason is in the > > cc & rc codes. > > > > 3) If the MQPUT did not complete / return then the > > application crashes, > > MQ > > does not have the message, hence, it is lost. > > > > Note: cc means Completion Code and rc means Reason > > Code. > > > > > > Hope that helps. > > > > > > Regards, > > Roger Lacroix > > Capitalware Inc. > > http://www.capitalware.biz > > > > To unsubscribe, write to > > [EMAIL PROTECTED] and, > > in the message body (not the subject), write: > > SIGNOFF MQSERIES > > Instructions for managing your mailing list > > subscription are provided in > > the Listserv General Users Guide available at > > http://www.lsoft.com > > Archive: > > > http://listserv.meduniwien.ac.at/archives/mqser-l.html > > > > To unsubscribe, write to > > [EMAIL PROTECTED] and, > > in the message body (not the subject), write: > > SIGNOFF MQSERIES > > Instructions for managing your mailing list > > subscription are provided in > > the Listserv General Users Guide available at > > http://www.lsoft.com > > Archive: > > > http://listserv.meduniwien.ac.at/archives/mqser-l.html > > > > > > > ____________________________________________________________________________________ > Do you Yahoo!? > Everyone is raving about the all-new Yahoo! Mail beta. > http://new.mail.yahoo.com > > To unsubscribe, write to [EMAIL PROTECTED] and, > in the message body (not the subject), write: SIGNOFF MQSERIES > Instructions for managing your mailing list subscription are provided in > the Listserv General Users Guide available at http://www.lsoft.com > Archive: http://listserv.meduniwien.ac.at/archives/mqser-l.html > -- Hubert Kleinmanns Beratung / Schulung / Projektleitung Tel.: +49 (0) 60 78 / 7 12 21 Fax: +49 (0) 60 78 / 7 12 25 Mobil: +49 (0) 178 / 6 97 22 54 To unsubscribe, write to [EMAIL PROTECTED] and, in the message body (not the subject), write: SIGNOFF MQSERIES Instructions for managing your mailing list subscription are provided in the Listserv General Users Guide available at http://www.lsoft.com Archive: http://listserv.meduniwien.ac.at/archives/mqser-l.html
