| Author |
Message
|
| ArthurNL |
 Posted: Fri Jul 31, 2009 3:51 am Post subject: message selectors in MQ V7 |
 |
|
Newbie
Joined: 07 Apr 2008
Posts: 5
|
Hi,
I am having a look at MQ V7 Publish/Subscribe.
One of the options in MQ V7 is the use of message selectors on the MQOPEN and MQSUB calls. Using this message selectors, it is possible to filter messages using the SQL92 specification.
The use of message selectors is also described in:
http://publib.boulder.ibm.com/infocenter/ieduasst/v1r1m0/topic/com.ibm.iea.wmq_v7/wmq/7.0/MQI/iea_330_wmqv7_API_3_Selectors.pdf
On a MQSUB call, you can specify a filter in the SelectionString field of the Subscription Descriptor structure. Subsequent MQGET calls will get only those messages that match the filter.
However, the following issues are not clear to me:
1. To what part of the message is the filtering applied, message header of message data?
2. If applicable to message header, how do I set this selection criteria using MQPUT?
Thanks for your response !!
Arthur |
|
| Back to top |
|
 |
| manicminer |
| Posted: Fri Jul 31, 2009 5:12 am Post subject: |
|
|
Disciple
Joined: 11 Jul 2007
Posts: 177
|
1. See slide 3 of your linked PDF 
"The query can select based on the values of ANY message property", so you will need to have some message properties on the message that you MQPUT for the selector to select on.
2. use the message properties api when you put.
_________________
Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime. |
|
| Back to top |
|
|
| mqjeff |
| Posted: Fri Jul 31, 2009 6:00 am Post subject: |
|
|
Grand Master
Joined: 25 Jun 2008
Posts: 17447
|
Note that message properties are NOT contained in the BODY of the message.
If you need to do subscription filtering based on the BODY of the message, you need Message Broker.
Also note that message selectors are assigned at MQOPEN time and are not changeable at MQGET time. |
|
| Back to top |
|
|
| shashikanth_in |
| Posted: Fri Jul 31, 2009 10:52 am Post subject: |
|
|
Centurion
Joined: 26 Feb 2009
Posts: 123
|
You could look at MQSETMP - MQ Set Message properties API and other related APIs which are used to create and set message properties to a MQ message.
HTH |
|
| Back to top |
|
|
| ArthurNL |
| Posted: Sun Aug 02, 2009 11:33 pm Post subject: |
|
|
Newbie
Joined: 07 Apr 2008
Posts: 5
|
Thank you all for your replies.
I managed to get it work using the MQSETMP call.
Arthur. |
|
| Back to top |
|
|
| WBIMaestro |
| Posted: Fri Sep 28, 2012 1:54 pm Post subject: |
|
|
Acolyte
Joined: 18 Feb 2005
Posts: 53
|
| at the risk of being chided for posting on an old post - what MQMD fields can I use selector API on? it is not too clear to me from the documentation. it looks like I can use any MQ MEssage properties fields, but the broker dosent really recognize Message properties does it? If I update the MQRFH2 header fields in the message will it show up as an MQ Message property when browsed using selector API from the queue? |
|
| Back to top |
|
|
| fjb_saper |
| Posted: Fri Sep 28, 2012 8:30 pm Post subject: |
|
|
Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
|
| WBIMaestro wrote: |
| at the risk of being chided for posting on an old post - what MQMD fields can I use selector API on? it is not too clear to me from the documentation. it looks like I can use any MQ MEssage properties fields, but the broker dosent really recognize Message properties does it? If I update the MQRFH2 header fields in the message will it show up as an MQ Message property when browsed using selector API from the queue? |
What have you tried and with what type of results? 
_________________
MQ & Broker admin |
|
| Back to top |
|
|
| mqjeff |
| Posted: Fri Sep 28, 2012 9:21 pm Post subject: |
|
|
Grand Master
Joined: 25 Jun 2008
Posts: 17447
|
Broker selectors work on logical message tree paths.
MQ selectors work on message properties.
Broker currently acts as a non-property aware application that converts all properties to RFH2 fields and vice versa. So if you want to create a broker selector on an mq message property, you'll need to use a Trace node to dump out the message tree to find out what the path to the property you want is - likely Root.MQRFH2.usr.<property>, but it's best not to guess, just test. |
|
| Back to top |
|
|
| WBIMaestro |
| Posted: Mon Oct 01, 2012 7:22 am Post subject: |
|
|
Acolyte
Joined: 18 Feb 2005
Posts: 53
|
I set the MQRFH2.usr folder with name value pairs and dumped it out to a trace file. I dont see it showing up as an MQ message Property. only as MQMD.MQRFH2.usr...
How/where does this broker conversion from MQRFH2 to message property occur? |
|
| Back to top |
|
|
| mqjeff |
| Posted: Mon Oct 01, 2012 7:32 am Post subject: |
|
|
Grand Master
Joined: 25 Jun 2008
Posts: 17447
|
| WBIMaestro wrote: |
| How/where does this broker conversion from MQRFH2 to message property occur? |
When the message is written to the queue, MQ does the conversion. Not broker.
If you pass it to an MQOutput, then amqsbcg should show properties and not the rfh2.
it might still show an RFH2, though, but applications that ask for properties will get properties anyway. |
|
| Back to top |
|
|
| WBIMaestro |
| Posted: Tue Oct 02, 2012 9:45 am Post subject: |
|
|
Acolyte
Joined: 18 Feb 2005
Posts: 53
|
so, my data looks as follows in the Msg Browse :
| Code: |
'RFH ........"...'
'....MQSTR ....'
'....d...<usr><Pr'
'operty1>AAAA</Pr'
'operty1><Propert'
'y2>BBBB</Propert'
'y2><Property3>CC'
'CCCCCCCCC</Prope'
'ty3></usr>......'
'<mcd><Msd>xmlnsc'
'</Msd></mcd><?xm'
'l version="1.0" '
'encoding="iso-88'
'59-1"?>..
|
What should the selector API be querying on - MQProperty.usr.Property1?
what would be the path to the property set in this way? |
|
| Back to top |
|
|
| fjb_saper |
| Posted: Wed Oct 03, 2012 8:15 pm Post subject: |
|
|
Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
|
Have you tried to use a selector with a very simple:
| Code: |
| propertyname=propertyvalue |
_________________
MQ & Broker admin |
|
| Back to top |
|
|
| WBIMaestro |
| Posted: Mon Oct 08, 2012 5:50 am Post subject: |
|
|
Acolyte
Joined: 18 Feb 2005
Posts: 53
|
| I checked in Mq Explorer and can see the properties set under 'named properties'. However having a tough time putting together code to browse/get the messages based on properties. the information seems to be scattered all over the api guide and mixed up between jms, pub sub and simple MQ API based calls to get from a queue based on properties. Would you know of a sample program and source code(C/C++) that I can look at for the latter (simple MQ API based calls to get from a queue based on properties)? thanks |
|
| Back to top |
|
|
| fjb_saper |
| Posted: Mon Oct 08, 2012 12:09 pm Post subject: |
|
|
Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
|
Read up in the programming manual on how to use a selector outside of JMS / XMS. This should guide you in the right direction.
_________________
MQ & Broker admin |
|
| Back to top |
|
|
| sojourner |
| Posted: Sat Jun 21, 2014 1:55 pm Post subject: |
|
|
Newbie
Joined: 21 Jun 2014
Posts: 1
|
| I concur with Arthur, I have read the manual and scoured the internet but still can not figure out how to set the message selector on the queue open or queue manager using the java mq api. If someone has accomplished this a simple code snippet would be awesome. |
|
| Back to top |
|
|
|
|
