I open the file extend I have been tasked with finding data there are certain cases that are not easily found so I have to search a large number of files on the off chance that 2 jobs write to the duke if it’s corrupted I can run it again it won’t happen and like I said it’s not production if it was that would change things
> On Mar 26, 2021, at 9:54 AM, Paul Gilmartin > <[email protected]> wrote: > > On Fri, 26 Mar 2021 09:21:59 -0400, Joseph Reichman wrote: > >> The chances of two jobs writing to the file are slim and none I am searching >> a large number of files because I cannot find the data >> > https://en.wikipedia.org/wiki/Murphy%27s_law > >> And most importantly it is NOT a production job >> > It seems unusual to be "searching a large number of files" in what > "is NOT a production job". > > What is your procedure for detecting contention? What is your recovery > process? > > I'll suggest using for output a UNIX file opened with O_APPEND. Be sure > your writes are atomic. > > >> -----Original Message----- >> From: Jeremy Nicoll >> Sent: Friday, March 26, 2021 9:13 AM >> ... >> That won't work if two jobs simultaneously try to write to the file. >> >> You might not destroy the file, but you will lose the information that the >> second job tried to write to it. >> >> The jobs need >> >> (a) not to allocate the output dataset at all in the JCL >> >> (b) to have a retry loop that does something like the >> following when you want to write data out >> >> repeat >> try to get exclusive use of the results file >> > If you have authority, use S99WTDSN # ########################## > >> if that fails and we've tried many times, >> perhaps write the data somewhere else? >> - though that might also fail >> stop trying >> end >> >> if exclusive use isn't acquired but we've not tried >> often, wait a bit (a random time interval) and >> try again >> >> if exclusive use was granted, update the file, >> free it again, and stop trying >> > Else? # ################################## > >> end > > -- gil > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
