IEBGENER BSAM or EXCP?



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IEBGENER BSAM or EXCP?

Postby daloporhecho » Tue May 10, 2011 1:29 am

Hello people, I hope you are all doing good. This is the problem:

I have an IEBGENER running every some minutes and it does most of the time work fine, reporting:

ICE084I 0 EXCP ACCESS METHOD USED FOR SYSUT2                                   
ICE084I 0 EXCP ACCESS METHOD USED FOR SYSUT1                                   
ICE751I 1 F4-BASE   F5-BASE   E8-K48846                                         
ICE090I 0 OUTPUT LRECL = 80, BLKSIZE = 6160, TYPE = FB                         


But it sometimes does generate a dataset with allocation VB, 255, 27998 (instead of FB, 80, 6160) and then IEBGENER reports:
ICE084I 0 BSAM ACCESS METHOD USED FOR SYSUT2                                   
ICE084I 0 EXCP ACCESS METHOD USED FOR SYSUT1                                   
ICE751I 1 EF-K49535 F0-K49038 E8-K48846                                         
ICE090I 0 OUTPUT LRECL = 80, BLKSIZE = 6160, TYPE = FB                         


Does anyone have a guess on why IEBGENER could be choosing BSAM instead of EXCP and if that could be the reason the allocation definition is not respected in the practice? This is causing trouble at the time of the next IEBGENER as it abends with "CONFLICTING DCB PARAMETERS" (Obviously, I don't need a VB, 255, 27998, but a FB, 80, 6160 instead). Now why IEBGENER could be doing that, is a mystery to me.

Thanks a lot for your guidance.
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Re: IEBGENER BSAM or EXCP?

 

Re: IEBGENER BSAM or EXCP?

Postby Akatsukami » Tue May 10, 2011 1:44 am

Is your input such that it requires a VB 255 data set? You don't post your JCL, but if SYSUT1 is a library of Rexx scripts or CLISTs, this is very likely the reason.
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Re: IEBGENER BSAM or EXCP?

Postby enrico-sorichetti » Tue May 10, 2011 2:21 am

remember, or better NOTICE that You are not using IEBGENER as per
http://publibz.boulder.ibm.com/cgi-bin/ ... 0521090625

but the IEBGENER <facility> provided by DFSORT
see the ICE messages

meditate on the conflicting wording
But it sometimes does generate a dataset with allocation VB, 255, 27998 (instead of FB, 80, 6160) and then IEBGENER reports:

ICE084I 0 BSAM ACCESS METHOD USED FOR SYSUT2
ICE084I 0 EXCP ACCESS METHOD USED FOR SYSUT1
ICE751I 1 EF-K49535 F0-K49038 E8-K48846
ICE090I 0 OUTPUT LRECL = 80, BLKSIZE = 6160, TYPE = FB

I tend to trust more the system than the TS

analyze better the jcl stram used and the characteristic of the dcb of the output dataset

the reason why dfsort uses BSAM rather than excp is explained in the dfsort manuals
cheers
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Re: IEBGENER BSAM or EXCP?

Postby daloporhecho » Tue May 10, 2011 3:01 am

Thank you Enrico, I'm following your advice and started to investigate into DFSORT manuals. But just in case I'm not as smart as you think I am:

This is the SQL:

//STEP01  EXEC PGM=IEBGENER                                       
//STEPLIB  DD  DSN=MYLIBRARY,DISP=SHR                   
//*                                                               
//SYSIN    DD  DUMMY                                               
//*                                                               
//SYSUT1   DD  DSN=MYGDG(0),DISP=OLD
//SYSUT2   DD  DSN=MYGDG(+1),       
//             DISP=(,CATLG,DELETE),                               
//             UNIT=MYUNIT,                                     
//             SPACE=(CYL,(40,20),RLSE),                           
//             DCB=(GDG,RECFM=FB,LRECL=80,BLKSIZE=6160)           
//SYSPRINT DD  SYSOUT=R                                           


The purpose is to create a new GDG generation from the current generation. It does always work good, but from time to time the utility decides to use BSAM and (apparently) changes the output allocation from the stated (FB, 80, 6160) to (VB, 255, 27998). Next time it runs, SYSUT1 won't be FB, 80, 6160 and then will report CONFLICTING DCB PARAMETERS. It does not happen when the utility reports using EXCP as the access method for SYSUT2.
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Re: IEBGENER BSAM or EXCP?

Postby enrico-sorichetti » Tue May 10, 2011 3:25 am

when according to Your investigantion the dcb is not what You are expecting
check the input dataset DCB also

I just run a few tests and for input and output FB dataset the access method will be EXCP

for VB input ...
the output MUST be VB, otherwise You will get an error
SORT realizes that something is fishy and will invoke the original IEBGENER
which in turn will terminate with a 12 RC and the message
DATA SET UTILITY - GENERATE
IEB311I CONFLICTING DCB PARAMETERS


for VB input and output the access metho will usually be EXCP for input BSAM for output

input ddname SYSUT1
output ddname SYSUT2

so the best thing to do is to review Your environment
id the output is VB it depends on the fact that the input is VB
cheers
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Re: IEBGENER BSAM or EXCP?

Postby daloporhecho » Tue May 10, 2011 3:39 am

Yes Enrico, the input dataset is the output dataset from the previous run. You may not be able to test it as here is working brilliantly most of the time. Only from time to time, days, perhaps weeks, it does abend with CONFLICTING DCB PARAMETERS.
For some reason (I'm trying to find out), the utility is generating an odd allocation configuration (VB, 255, 27998) instead of the usual (FB, 80, 6160). When that happens, IEBGENER will report having used BSAM access method as SYSUT2 (in contrast when it works fine it does always uses EXCP as access method).
Please, follow me: the input dataset is the output dataset from the previous run. The output dataset from this run will be the input dataset from next run.
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Re: IEBGENER BSAM or EXCP?

Postby enrico-sorichetti » Tue May 10, 2011 3:51 am

do not blame the utilities for the wrong allocation parameters
the system simply reacts to the data being presented

Please, follow me: the input dataset is the output dataset from the previous run. The output dataset from this run will be the input dataset from next run.

I value too much my life to follow You along the wrong path!
the description of the process is al least flaky... no reason to keep copying the same thing over and over
something must happen in between to the input dataset,

anyway You did not provide any fact/data to analyze ... You are just reporting that something does not work according to Your expectations.
You assume that everything is right, I suggest on the other side to review all the facts in order to consolidate them in proper findings!
cheers
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Re: IEBGENER BSAM or EXCP?

Postby Robert Sample » Tue May 10, 2011 4:22 am

The absolute biggest mistake newcomers to IT make -- and it happens every day -- is to have a problem occur and immediately assume that the system did something wrong. While this does happen -- once in a great while -- the vast majority of the time, the person either is misinterpreting what the system is telling them, or they are making some other basic mistake that is causing the issue.

The BSAM / EXCP difference is most likely a symptom, not a cause, of your problem. You have not posted any real JCL (which is the term, by the way, not SQL). Have you talked to your site support people to see if an ACS routine for storage management is changing your DCB parameters automatically? Have you talked to the site support group about your JCL? Why are you using a STEPLIB for a system utility (which should be in a system library available without a STEPLIB)? Have you looked at the differences in the jobs between the two outcomes -- there has to be SOME difference, whether or not you've noticed it?
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Re: IEBGENER BSAM or EXCP?

Postby BillyBoyo » Tue May 10, 2011 5:09 am

[quote="daloporhecho"]
//STEP01  EXEC PGM=IEBGENER                                       
//STEPLIB  DD  DSN=MYLIBRARY,DISP=SHR                   
//*                                                               
//SYSIN    DD  DUMMY                                               
//*                                                               
//SYSUT1   DD  DSN=MYGDG(0),DISP=OLD
//SYSUT2   DD  DSN=MYGDG(+1),       
//             DISP=(,CATLG,DELETE),                               
//             UNIT=MYUNIT,                                     
//             SPACE=(CYL,(40,20),RLSE),                           
//             DCB=(GDG,RECFM=FB,LRECL=80,BLKSIZE=6160)           
//SYSPRINT DD  SYSOUT=R                                           


Might be a red herring, but what is that in your DCB? Just a typo from formatting for here?

What do you do after a job crashes, how do you get it going again?

What is the DCB info for the input of a job that crashes, and of the previous generation of the file?

What does the DATA look like when the file "magically" becomes VB?

Something else is changing your file. Your output message, with the BSAM, shows FB. Your job ran creating FB. By the time your next job ran, the file was VB so your next job crashed. After you created the catalog entry, something changed it.

255. Suspicious number. Looks like a PDS DCB? Anyone been "editing" the file in TSO?
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Re: IEBGENER BSAM or EXCP?

Postby daloporhecho » Tue May 10, 2011 6:23 am

Robert, wasn't it SQL? Jesus, I'm using the wrong tool!
Billy, what typo in the DCB are you talking about?
Enrico: bacio.

I'm gonna come back with a solution, because something weird is going on and it's not meeeee.
Thank you, guys.
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