Thanks Robert. That is exactly what I was thinking. Will be running a test early next week. Regards, Mike Kovach
________________________________ From: Robert A. Rosenberg <[email protected]> To: [email protected] Sent: Thursday, April 5, 2012 4:03 PM Subject: Re: A deep question about VSAM SHR(4) - can you help? At 07:16 -0700 on 04/05/2012, Mike Kovach wrote about A deep question about VSAM SHR(4) - can you help?: > I have a VSAM KSDS CLUSTER which is written to by ONLY ONE PROGRAM in ONLY > ONE CICS REGION. Currently, this file is defined in CICS with STRNO(1). The > file is defined with SHR(4,3) because while being written ONLY in CICS, it is > being read by a non-reentrent ASSEMBLER program running in BATCH. SHR 4 > forces VSAM to harden each I/O (yeah, I know!) so the BATCH gets the current > information. Please spare me all the comments about how poor this solution is > as it stands. It has been in place for decades and due to a myriad of > reasons, the philosophy CANNOT change. My specific question is this: I want > to introduce multi tasking so that 5 copies of the program can update the > file concurrently. If we change STRNO(1) to STRNO(5) on the CICS FCT > Definition, will VSAM be smart enough to manage the writes to the file so we > don't break it and the BATCH still gets the current information? So long as you are still using one CICS Region, I do not think you will run into problems. The STRNO(5) will allow you to have 5 CIs being updated at a time (one CI per copy of the program). If more than one copy attempts to access records from the same CI, it should cause the subsequent requesters to wait for the owning copy to finish its update and release/write the CI (just make sure that all your VSAM is being done by SubTasks which I think CICS does automatically). You should increase the number of buffers so there are enough for all the copies. > I am interested in any discussion you might share, but I am most interested >in a specific reference to a reliable document. Please help. Thanks Mike >Kovach > > ---------------------------------------------------------------------- > 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 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
