RCVJRNE command impact

rajsubhyd

105 pts.

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AS/400 commands

RCVJRNE

Hi, I am using five different programs to monitor the changes and catch them through RCVJRNE command using EXITPGM . There are lot of other files attached to the same journal. By using the RCVJRNE command on only 1 or 2 file will have any imapct on other files? What is the impact on the performance of the server?

Software/Hardware used:
AS400

Asked: November 20, 2009 12:37 PM Last updated: December 1, 2009 11:49 PM

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Last updated: November 21, 2009 12:55 AM GMT

TomLiotta125,585 pts.
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- TomLiotta125,585 pts.

Thanks. We'll let you know when a new response is added.

Any time any program executes instructions, those CPU cycles are unavailable to any other program, just like any system resource.

However, there is little or no practical relationship between the journal entry processing done by your programs and the database processing going on in other jobs, as long as your journal programs don’t also access the files directly.

If you have a program that receives journal entries for a particular file and there are no processes that are updating that file, then your journal program won’t be taking up any significant system resources at all. It won’t have any work to do — it’ll just be waiting. There will be no impact on any other job.

If you have a process that’s generating 10 journal entries per second against that file and your journal program receives individual entries, then your journal program will be called 10 times per second — assuming it can complete its work that fast; it might lag behind if it’s inefficient. If your journal program has requested a block of 10 entries, then it will only be called once per second, on average. (Not exactly, but that expresses the idea.)

Tom

Discuss This Question: 5 Replies

philpl1jb Nov 21, 2009 11:25 AM GMT

tom's got it. The RCVJRNE doesn't use any of your physical files. It might slow down slightly all updates being processed by that journal while it's running it would use machine cycles, and could slow down all processes, slightly, while it's running. Phil

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rajsubhyd Nov 22, 2009 11:39 AM GMT

Thank you Tom and Phil for your answers. To be most specific There are other fiels which are attched to the same journal, we would like to know by extracting the journal entry of 5 or 6 files will this impact anything on the journal performance with respect to the other files, I mean will it be slow in performing journal operations for other files. Appreciate if you can provide some details in this aspect.

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philpl1jb Nov 24, 2009 2:31 AM GMT

If the system isn't overloaded, if you're only capturing a few journal entries, the impact should not affect your other processes. Phil

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TomLiotta Nov 24, 2009 11:02 PM GMT

...if you can provide some details in this aspect. There are far too many variables and the question is too vague. As noted, there is always a performance impact every time any program runs. For journal processing, it can be complicated. In a perhaps ideal setup, you would want your journal receiver in a user ASP consisting of mirrored drives. Also, the user ASP should have no other activity except the journal functions. This allows journal entries to be deposited as much as possible in consecutive disk sectors. There would be essentially no disk arm movement to write next entries. And because it's mirrored, reads can come from whichever disk has a disk arm closest to the data being sought. But you rarely see setups approaching "ideal". Does it describe your system? If not, then what is your system configuration? How many drives? (How many arms?) What journaling is done? What database activity happens in the same ASP? (How much is journaled?) Is commitment control always active? Sometimes? Never? What kinds of referential constraints exist? (How many of them are actively involved in common activity?) What will your journal entry requests look like? Single entries? Buffered blocks? (How many entries per block?) Will you have individual and separate jobs for each file that entries will be received for? Or will it be one job that will receive all entries and call different programs to process entries for different files? What is your normal CPU usage? Has any performance tuning been applied to the system? What is the usual disk usage? How much extra capacity is available? Generally, you're not going to see significant difference. The only good way to get a picture will be to try it. If it isn't satisfactory, focus on fixing whatever element causes the biggest drag. Tom

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Whatis23 Dec 1, 2009 11:49 PM GMT

I would agree that you’re not going to see significant difference. Several companies i've worked for have used some sort of HA software which are notorious for using journals and every related cmd possible. That being said, i did not see any noticable impact on performance.

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