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| How to test an XA configuration |
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| hopsala |
 Posted: Tue Jan 31, 2012 4:25 am Post subject: How to test an XA configuration |
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Guardian
Joined: 24 Sep 2004
Posts: 960
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Hey
So I've got a V7 broker with a V7.1 QM. After a bit of floundering about, I seem to have successfully configured the QM to coordinate transactions with an Oracle DB on another machine, and all were happy in lego-land.
Thing is, how do I test if it's working? The broker and QM are up and running (which is already an accomplishment), and even without XA coordination I've got basic transactionality going. For example, the following flow:
MQInput > Compute (DB INSERT) > MQOutput > Throw
doesn't write to db or to MQ regardless of whether the "coordinated transaction" flag on the BAR file is checked.
So how do I test if my XA config is running properly? any ideas? |
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| mqjeff |
| Posted: Tue Jan 31, 2012 4:30 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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First off, XA isn't used unless the Global Transaction box is checked. But you know that Broker always does it's best effort to coordinate transactions even without XA enabled.
So that's why your flow "works" if you don't set the Global Transaction, because Broker is making best efforts to perform local transaction coordination - and broker is pretty good at this.
If you want to ensure that your XA configuration is correct, then make sure you do enable the Global Transaction. Then perform a transaction of some kind - i.e. use a flow that starts with an MQ node to perform an update on a database.
If the XA configuration isn't working, then this will fail spectacularly and noisily. If the XA configuration is correct, then it will work silently.
If you somehow actually are required by your <deleted/> customer to "verify XA", you will either have to tell them to trust the product or concoct ridiculous methods, i.e. removing network cables at strategic microseconds, to generate an XA failure case that is not covered by broker normal transactional handling. |
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| hopsala |
| Posted: Tue Jan 31, 2012 4:54 am Post subject: |
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Guardian
Joined: 24 Sep 2004
Posts: 960
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Hello Jeff, a quick and pertinent reply as always.
| mqjeff wrote: |
First off, XA isn't used unless the Global Transaction box is checked. But you know that Broker always does it's best effort to coordinate transactions even without XA enabled.
So that's why your flow "works" if you don't set the Global Transaction, because Broker is making best efforts to perform local transaction coordination - and broker is pretty good at this. |
So far I'm with you, and this is why I asked why I asked.
| mqjeff wrote: |
| If you somehow actually are required by your <deleted/><replace="marvelous"/> customer to "verify XA", you will either have to tell them to trust the product or concoct ridiculous methods, i.e. removing network cables at strategic microseconds, to generate an XA failure case that is not covered by broker normal transactional handling. |
is exactly what I'm trying to avoid..
| mqjeff wrote: |
If you want to ensure that your XA configuration is correct, then make sure you do enable the Global Transaction. Then perform a transaction of some kind - i.e. use a flow that starts with an MQ node to perform an update on a database.
If the XA configuration isn't working, then this will fail spectacularly and noisily. If the XA configuration is correct, then it will work silently. |
?
Apparently I don't quite get what you mean. Isn't this exactly what I did? I mean:
| hopsala wrote: |
MQInput > Compute (DB INSERT) > MQOutput > Throw
doesn't write to db or to MQ regardless of whether the "coordinated transaction" flag on the BAR file is checked. |
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| mqjeff |
| Posted: Tue Jan 31, 2012 4:58 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| hopsala wrote: |
| mqjeff wrote: |
If you want to ensure that your XA configuration is correct, then make sure you do enable the Global Transaction. Then perform a transaction of some kind - i.e. use a flow that starts with an MQ node to perform an update on a database.
If the XA configuration isn't working, then this will fail spectacularly and noisily. If the XA configuration is correct, then it will work silently. |
?
Apparently I don't quite get what you mean. Isn't this exactly what I did? I mean:
| hopsala wrote: |
MQInput > Compute (DB INSERT) > MQOutput > Throw
doesn't write to db or to MQ regardless of whether the "coordinated transaction" flag on the BAR file is checked. |
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Yes, that is exactly what you did. Except for that pesky throw node. It allows you to demonstrate that both transactions are rolled back, but that's a negative acknowledgement.
Again, if the XA configuration is incorrect, then you will either get a lot of errors when you deploy the flow WITH Global Transaction checked (again, no XA is invovled if this is *not* checked), or you will get a lot of errors when the flow attempts to use the database connection.
If you DO NOT see these errors, and you're SURE that Global Transaction is checked (i.e. you can see this in the deployed properties of the flow), then your configuration is correct.
And then either Broker's XA code works, or it doesn't. This is, again, where you tell the <deleted/> client to TRUST THE CODE. |
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| hopsala |
| Posted: Tue Jan 31, 2012 5:10 am Post subject: |
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Guardian
Joined: 24 Sep 2004
Posts: 960
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| mqjeff wrote: |
Again, if the XA configuration is incorrect, then you will either get a lot of errors when you deploy the flow WITH Global Transaction checked (again, no XA is invovled if this is *not* checked), or you will get a lot of errors when the flow attempts to use the database connection.
If you DO NOT see these errors, and you're SURE that Global Transaction is checked (i.e. you can see this in the deployed properties of the flow), then your configuration is correct. |
Ah! I was just wondering about that, tried to find some relevant reference in the info center. Should have mentioned I ran a similar flow earlier that finishes correctly (with MQOutput instead of Throw) with global coordination flagged, and it worked as expected - everything was committed. Which you say means XA is configured properly, which means another task checked off the infinite administration list. Grand!
| mqjeff wrote: |
| And then either Broker's XA code works, or it doesn't. This is, again, where you tell the <deleted/> client to TRUST THE CODE. |
Oh yes, and we all know how clients like to listen to REASON..
Thanks!  |
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