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>The UB and the UP entries are generated from the same database instruction, >which is why they are guaranteed to hit the *JRNRCV in a 1,2 sequence. I'm not doubting that this is true, just confused by it. A "database instruction" is still made up of mutiple RISC opcodes, no? On a pre-emptive multi-tasking system like OS/400 it's possible for a job to be swaped out at any time, no? Therefore, even on a uni-processor why is this a guarentee? Not to mention the fact that on a multi-processor two jobs could truly be running at the same time. Now, I could see this being true if all db updates in the system were actually funneled through a single thread or mutex, but that seems like a bottleneck, no? -Walden ------------ Walden H Leverich III President Tech Software (516) 627-3800 x11 (208) 692-3308 eFax WaldenL@xxxxxxxxxxxxxxx http://www.TechSoftInc.com Quiquid latine dictum sit altum viditur. (Whatever is said in Latin seems profound.) -----Original Message----- From: Al Barsa [mailto:barsa@xxxxxxxxxxxxxxxxxxx] Sent: Friday, September 05, 2003 10:06 AM To: Midrange Systems Technical Discussion Subject: Re: Are journal's UB & UP entries guaranteed to be in 1-2 sequence? The UB and the UP entries are generated from the same database instruction, which is why they are guaranteed to hit the *JRNRCV in a 1,2 sequence. Al - unsure if I like being a fish for a week on Orlando Al Barsa, Jr. Barsa Consulting Group, LLC 400>390 914-251-1234 914-251-9406 fax http://www.barsaconsulting.com http://www.taatool.com G Armour <garmour400m@yaho o.com> To Sent by: Midrange Systems Technical midrange-l-bounce Discussion s+barsa2=attgloba <midrange-l@xxxxxxxxxxxx> l.net@xxxxxxxxxxx cc m Subject Re: Are journal's UB & UP entries 09/05/2003 09:30 guaranteed to be in 1-2 sequence? AM Please respond to Midrange Systems Technical Discussion <midrange-l@midra nge.com> I was going to ask for documentation references, but if Al says it... BTW, Al, did you mean to say "precede"? Actually, I presumed that a UB would always precede a UP, but my bigger question is whether there was a possibility of an interceding entry between the UB & UP entries for the same database record. If I had 1000 users in the same program that were updating 1000 different records (1 each per user) in the same file, and they all hit the Enter key to update the record at the same time, will IBM guarantee that I won't encounter a scenario like: Journal Sequence# Type Record's Key 201 UB AAAAAAAAAAA (From user Joe) 202 UB BBBBBBBBBBB (From user Fred) 203 UP AAAAAAAAAAA (From user Joe) 204 UP BBBBBBBBBBB (From user Fred) This example shows that there is an interceding UB entry (202) between the UB & UP entries for the record with key AAAAAAAAAAA. If this is possible, I need to build an array of UB entries in my RCVJRNE exit program, and Look-Up that array whenever I process a UP entry so that I can compare the changes made to the record. Obviously, I would rather not have to deal with such an array in this program, but if I can't be sure that the above scenario will never happen, then I'll need to. Advice & suggestions welcomed. GA --- Al Barsa <barsa@xxxxxxxxxxxxxxxxxxx> wrote: > You are absolutely guaranteed that a UB will immediately proceed a UP. > > Al > > Al Barsa, Jr. > Barsa Consulting Group, LLC > > 400>390 > > 914-251-1234 > 914-251-9406 fax > > http://www.barsaconsulting.com > http://www.taatool.com > > > From G Armour: garmour400m@xxxxxxxxx> > > Are an update record's UB (Update Before) & UP (Update After) entries > guaranteed (no quibble, rock-solid, cross-my-heart) to be in 1-2 > sequence, > with NO possibility of another entry being written between them? I > could > not find any reference to this in the manuals, and so I must now presume > the possibility exists and must store the UB entries in an array, > waiting > for the UP entry to arrive and match to the UB entry by JOCTRR (the > RRN)? > Since the program is RETURNed without setting LR on after each entry is > processed, the UB entries will still remain in the array on subsequent > calls to the program, correct? > > I am writing an exit program to a RCVJRNE command. I need to compare > before & after images on an update to a record to determine if I need to > take a specific action. The files being journaled are getting both the > before & after images journaled. > > Also, as I now see that the exit program is RETURNed without LR on after > *each* journal entry, doesn't that have the potential to be a resource > drain? > > TIA, GA __________________________________ Do you Yahoo!? Yahoo! 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