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| HBINT 0 for RCVR |
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| pmane |
 Posted: Wed Sep 04, 2002 4:16 am Post subject: HBINT 0 for RCVR |
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Acolyte
Joined: 17 Oct 2001
Posts: 50
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What dose it mean if I have HBINT 0 for my RCVR channel ? I understand that it will not exchange the hart beat. What I do not get is if I exchange the HBINT or don't what diffrence it will make any way. According to IBM
"The heartbeat exchange gives the receiving MCA the opportunity to quiesce the channel" But why will I want my channel to stop any way ? Is it a over head to keep the channel running ? If I have a system that needs 24/7 then should I keep HBINT to 0 ?
On my sender channel if I want to make sure that the channel is on for ever then if I put DISCINT = 0 will I get the effect ? What if my partner reciver keeps the channel HBINT to 10 will my channel stop after while ?
Is it over head to keep the channel on for ever ?
what is keep alive ? and is it replated to keeping channel alive ? Is it a over head ?
Do we have list of things that can make the channel down. I want to create test cases and make sure my application will start it automaticaly some how. Do I need to bother about the channel down or it is taken care by IBM MQ already. As even if I pull out the network cable and reconnect it my MQ dose not complain about the channel down Infact it dose not know . |
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| PeterPotkay |
| Posted: Mon Sep 09, 2002 6:02 pm Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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| Quote: |
What dose it mean if I have HBINT 0 for my RCVR channel ?
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First rule to remember is that when the sides of a channel have 2 different values for heartbeat, the larger of the 2 is used, so both the SNDR and RCVR will have to be set at 0, unless 0 at either end overides this rule???
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But why will I want my channel to stop any way ? Is it a over head to keep the channel running ?
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From the Intercommunications handbook...A very large value (more than an hour) could mean that system resources are unnecessarily held up.
They dont go into detail on what that means, but I do know that when an MCA on the recieving side puts to the local queue on that side, it leaves that queue open until the channel goes inactive, cuz the MCA doesn't know when the next message may come for that queue, so why not save unnecessary OPENs/CLOSEs on that queue. If the channel stays up forever, than those queues stay open for output forever. No big deal, but there are some things you cant do to an open queue (clear it, delete it).
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If I have a system that needs 24/7 then should I keep HBINT to 0 ?
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NO! Quite the contrary, you should use heartbeat. The whole purpose of HB is to allow the RCVR to go inactive in case the channel goes down cuz of network issues. You need an RCVR in an inactive state cuz when the network does come back up and the SNDR retries, it will only connect if it finds the RCVR in an inactive state. So yeah, if your channels never go down because of problems, then HB isn't needed. But sooner or later, your channel will go down because of a problem (regardless of what the DISCINT is), and then HB will allow your SNDR to reestablish communication with the RCVR. No HB? Now you gotta get involved and manually get that RCVR in a state where it can accept the SNDR's request.
(An additional consideration for all this is AdoptMCA. Do a search on this term to see our posts on this related subject http://www.mqseries.net/phpBB/viewtopic.php?t=4736&postdays=0&postorder=asc&highlight=adoptmca&start=0)
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On my sender channel if I want to make sure that the channel is on for ever then if I put DISCINT = 0 will I get the effect ?
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Yes, assuming no problems bring the channel down for other reasons.
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what is keep alive ? and is it replated to keeping channel alive ? Is it a over head ?
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If you specify this option, TCP periodically checks that the other end of the connection is still available, and if it is not, the channel is terminated. I would guess there is some tiny overhead as both sides "talk" to each other to see that they are still there. (fyi heartbeat packets are only 12 bytes).
By the way, check out this post also. It talks about channels being up forever.
http://www.mqseries.net/phpBB/viewtopic.php?t=4721&highlight=channel
We made some of our channels stay up forever. One project needs its replies in 500 milliseconds and hops thru 3 queue managers. The act of starting up channels was often enough to push the roundtrip time over 500 ms. I changed all the channels needed for this app to be up all the time and the timeout prob went away.
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Peter Potkay
Keep Calm and MQ On |
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