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| WS MQFTE V7.0 combo with classic FTP in progress - Issue |
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| mqjeff |
 Posted: Tue Feb 03, 2009 2:03 pm Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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I'm not disagreeing, and I completely understand about work hours and what there is time to do.
I'm just saying that I have personally experienced similar issues with IIS FTP server, outside of using WMQ FTE, and that it was not a pleasant experience for me.
Also, unfortunately, file locking problems are not unique to Windows. The NFS protocol doesn't support them, for example, and that is historically a Unix file protocol where file locks are pervasive.
The problem you'd like WMQ FTE to solve - 'is a file complete or not' - in the *general* case is almost certainly provably unsolvable. I haven't actually taken the time to write out a formal proof, but it amounts to the same problem as "did the program that is writing the file HALT" - that is, the halting problem! |
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| Nenad_SBS |
| Posted: Tue Feb 03, 2009 4:30 pm Post subject: |
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Newbie
Joined: 02 Feb 2009
Posts: 8
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| mqjeff wrote: |
...
The problem you'd like WMQ FTE to solve - 'is a file complete or not' - in the *general* case is almost certainly provably unsolvable. I haven't actually taken the time to write out a formal proof, but it amounts to the same problem as "did the program that is writing the file HALT" - that is, the halting problem! |
... please correct me if I miss something:
If this is unsolvable problem, recognized as halting or locking or whatever, (now, after this test) can I be sure that IIS FTP Server is just one and only "application" wich can result with corrupted file at the end of flow, until I take the time and try "everything", huh "everything"???, that can be used for "serving" file to MQ FTE Agent?
So, for me, next question is what for is this?
And, one more thing, so far, I can't find documented limitations (MQ FTE Documentation, manuals, etc) about this issue.
Best regards,
Nenad |
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| mqjeff |
| Posted: Wed Feb 04, 2009 3:54 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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It's unsolvable in the general case, not in a specific implementation.
There's a number of different ways that it can be solved more specifically than just "is this file complete or not?". A reliable file locking mechanism, for example... 
You've been given some specific recommendations on how to use WMQ FTE properly to avoid this issue - by using a small trigger file that can be transfered/created in a very short period of time.
You've been given a suggestion that using another FTP server may make it possible to do this transfer without using a trigger file.
I don't know that it's the proper role of the WMQ FTE documentation to warn users that FTP servers can do funny things, or that file locking mechanisms may not be as reliable as one thinks. |
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| Nenad_SBS |
| Posted: Wed Feb 04, 2009 2:06 pm Post subject: |
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Newbie
Joined: 02 Feb 2009
Posts: 8
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| mqjeff wrote: |
It's unsolvable in the general case, not in a specific implementation ...
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A reliable file locking mechanism, for example...
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I Agree (with compliments) 
| mqjeff wrote: |
| You've been given a suggestion that using another FTP server may make it possible to do this transfer without using a trigger file. |
This is also ok for me.
| mqjeff wrote: |
| I don't know that it's the proper role of the WMQ FTE documentation to warn users that FTP servers can do funny things, or that file locking mechanisms may not be as reliable as one thinks. |
What is the proper role of [any SW/HW ] documentation ?
I am not familiar with an "indirect ways" for solving problems, "indirect way" is "direct path to highway" of issues and complications. (this applies only to HW/SW, including design phase, developing/coding phase, testing phase, exploatation phase, new versions and releases, and so on)
Anyway, this is the place for changing opinions and ideas, giving suggestions and looking for something already invented 
Best regards,
Nenad |
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