Re: VSAM LSR
Paul, I have an application that has several VSAM datasets. These datasets currently use NSR (Non Shared Resources). The Application is written in assembler. I want to switch some of the Files to use LSR. If two files share a buffer pool do I need to concern my self with the contents of the buffer pool or is the Access Method handling that. In other words If I issue a VSAM GET for File A, is VSAM managing the contents of the LSR buffer pool with respect to the two files that may or may nor have records in the buffer pool ? Do I need to use any additional Assembler VSAM macros to manage the contents of the buffer pool ? I believe someone else mentioned batch LSR but you could use system managed buffering if the vsam datasets are SMS managed. It would be even less work than implementing batch LSR. My testing showed very good results such that I would problably not bother to setup LSR in an assembler program again. Regards, John -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
VSAM LSR
I have an application that has several VSAM datasets. These datasets currently use NSR (Non Shared Resources). The Application is written in assembler. I want to switch some of the Files to use LSR. If two files share a buffer pool do I need to concern my self with the contents of the buffer pool or is the Access Method handling that. In other words If I issue a VSAM GET for File A, is VSAM managing the contents of the LSR buffer pool with respect to the two files that may or may nor have records in the buffer pool ? Do I need to use any additional Assembler VSAM macros to manage the contents of the buffer pool ? Paul D'Angelo Weight Loss Program Best Weight Loss Program - Click Here! http://thirdpartyoffers.juno.com/TGL2141/c?cp=vnAEybPZGp-e7KXPyxS0vQAAJ1DMCvI8C_EKS4yGKHO7DleMAAYAAADNAAAEUgA= -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: VSAM LSR
-Original Message- From: IBM Mainframe Discussion List On Behalf Of esst...@juno.com I have an application that has several VSAM datasets. These datasets currently use NSR (Non Shared Resources). The Application is written in assembler. I want to switch some of the Files to use LSR. If two files share a buffer pool do I need to concern my self with the contents of the buffer pool or is the Access Method handling that. The access method handles the LSR buffering. In other words If I issue a VSAM GET for File A, is VSAM managing the contents of the LSR buffer pool with respect to the two files that may or may nor have records in the buffer pool ? Do I need to use any additional Assembler VSAM macros to manage the contents of the buffer pool ? No. -jc- -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: VSAM LSR
The access method (VSAM) manages the buffer pool and buffer lookasides. You just issue the GET(s). You must build the LSR pool before the OPEN of each VSAM file. If the datasets have different data/index CISIZES, you will need to build the pool accordingly. Also, if these are KSDS (indexed) VSAM files, you should look into building separate data and index LSR pools. Ideally, for the index, you would want to build it large enough to hold the upper levels of the index component plus a few for sequence set records. -Original Message- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of esst...@juno.com Sent: Monday, December 28, 2009 11:01 AM To: IBM-MAIN@bama.ua.edu Subject: VSAM LSR I have an application that has several VSAM datasets. These datasets currently use NSR (Non Shared Resources). The Application is written in assembler. I want to switch some of the Files to use LSR. If two files share a buffer pool do I need to concern my self with the contents of the buffer pool or is the Access Method handling that. In other words If I issue a VSAM GET for File A, is VSAM managing the contents of the LSR buffer pool with respect to the two files that may or may nor have records in the buffer pool ? Do I need to use any additional Assembler VSAM macros to manage the contents of the buffer pool ? Paul D'Angelo Weight Loss Program Best Weight Loss Program - Click Here! http://thirdpartyoffers.juno.com/TGL2141/c?cp=vnAEybPZGp-e7KXPyxS0vQAAJ1DMCv I8C_EKS4yGKHO7DleMAAYAAADNAAAEUgA= -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: VSAM LSR
All good points. However, with batch LSR, a few simple JCL changes should do the trick. And, oddly enough, the defaults are almost always suitable. -Original Message- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Larry Crilley Sent: Monday, December 28, 2009 12:49 PM To: IBM-MAIN@bama.ua.edu Subject: Re: VSAM LSR The access method (VSAM) manages the buffer pool and buffer lookasides. You just issue the GET(s). You must build the LSR pool before the OPEN of each VSAM file. If the datasets have different data/index CISIZES, you will need to build the pool accordingly. Also, if these are KSDS (indexed) VSAM files, you should look into building separate data and index LSR pools. Ideally, for the index, you would want to build it large enough to hold the upper levels of the index component plus a few for sequence set records. -Original Message- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of esst...@juno.com Sent: Monday, December 28, 2009 11:01 AM To: IBM-MAIN@bama.ua.edu Subject: VSAM LSR I have an application that has several VSAM datasets. These datasets currently use NSR (Non Shared Resources). The Application is written in assembler. I want to switch some of the Files to use LSR. If two files share a buffer pool do I need to concern my self with the contents of the buffer pool or is the Access Method handling that. In other words If I issue a VSAM GET for File A, is VSAM managing the contents of the LSR buffer pool with respect to the two files that may or may nor have records in the buffer pool ? Do I need to use any additional Assembler VSAM macros to manage the contents of the buffer pool ? Paul D'Angelo Weight Loss Program Best Weight Loss Program - Click Here! http://thirdpartyoffers.juno.com/TGL2141/c?cp=vnAEybPZGp-e7KXPyxS0vQAAJ1DMCv I8C_EKS4yGKHO7DleMAAYAAADNAAAEUgA= -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html NOTICE: This electronic mail message and any files transmitted with it are intended exclusively for the individual or entity to which it is addressed. The message, together with any attachment, may contain confidential and/or privileged information. Any unauthorized review, use, printing, saving, copying, disclosure or distribution is strictly prohibited. If you have received this message in error, please immediately advise the sender by reply email and delete all copies. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Are VSAM LSR statistics ever sent to SMF?
This is a followup to my series of questions about BLSR/SMB/LSR statistics back in May of this year. My capacity and performance gurus queried IBM at my request and came back to me to say that there ARE no VSAM LSR statistics sent to SMF. Can anyone here confirm or deny this statement? My CP gurus have said that they asked on IBMLink (to which I do not have access) and were told that no such statistics were sent to SMF after CLOSE of a VSAM LSR ACB. It just does not seem right or sensible to me that VSAM LSR code would keep statistics (see below) while the file is open but fail to write them out to SMF on CLOSE (whether by EOT/EOJ or user CLOSE). Especially for HLL code (COBOL, PL/1, etc.) that invokes BLSR or SMB via JCL, and not directly via programmer coding of a VSAM LSR ACB, it would be difficult to set up an assembler SHOWCB before CLOSE to extract such statistics from the ACB independently. Just locating the ACB in the first place would be non-trivial and possibly HLL release-dependent. TIA for your help in confirming or denying what I have been told. If VSAM LSR stats are in fact sent to SMF, I'd also appreciate a pointer to which SMF record to tell my CP gurus to look at. Peter P.S. -- I have been asked WHY do I want to see these statistics? Easy -- to help tune the optimal size of the pool for each file with finer-grained data than raw EXCP/SIO counts and total memory usage for the job. Performance of my application code is my responsibility, and I take it seriously. I want every tool I can find to help me with that job. Snippet from 05/10/2007 message to the list: It appears that VSAM LSR keeps certain statistics for each buffer pool from the time it is created to the time it is deleted. You can get the current values by using SHOWCB with an ACB that is already OPEN using LSR and that buffer pool. These are the available stats, according to z/OS V1R6.0 DFSMS: Using Data Sets: Field Description BFRFND The number of requests for retrieval that could be satisfied without an I/O operation (the data was found in a buffer). BUFRDS The number of reads to bring data into a buffer. NUIWThe number of nonuser-initiated writes (that VSAM was forced to do because no buffers were available for reading the contents of a control interval). STRMAX The maximum number of placeholders currently active for the resource pool (for all the buffer pools in it). UIW The number of user-initiated writes (PUTs not deferred or WRTBFRs, see Deferring Write Requests in topic 2.8.2.1). This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Heads Up: OA17292 Data Loss with VSAM LSR Hiperspace
Here's another interesting problem. OA17292 is an APAR against VSAM which describes a failure to correctly invalidate buffers stored in the hiperspace cache, which can result in downlevel data replacing current data and thus is flagged DATALOSS. The APAR text mentions IMS as being exposed. The defect, however, is within VSAM. I do not know if other VSAM LSR exploiters (such as CICS) are affected. I have asked that question. Interestingly, one of the APAR symptoms is errors flagged by an IMS pointer checker utility. I am unaware of a pointer checker for CICS VSAM files, so I do not know how one would know of data loss in a non-IMS environment. Keep in mind what I know about CICS (or IMS for that matter) I could easily write upon the head of a pin Brian -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Heads Up: OA17292 Data Loss with VSAM LSR Hiperspace
The question's answer is IMS and VSAM only are exposed. CICS is not. Brian On Thu, 3 Aug 2006 12:00:27 -0500, Brian Peterson [EMAIL PROTECTED] wrote: I do not know if other VSAM LSR exploiters (such as CICS) are affected. I have asked that question. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Heads Up: OA17292 Data Loss with VSAM LSR Hiperspace
-Original Message- From: IBM Mainframe Discussion List On Behalf Of Brian Peterson On Thu, 3 Aug 2006 12:00:27 -0500, Brian Peterson wrote: I do not know if other VSAM LSR exploiters (such as CICS) are affected. I have asked that question. The question's answer is IMS and VSAM only are exposed. CICS is not. Did that answer originate from DFSMS support? or CICS Support? -jc- -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Heads Up: OA17292 Data Loss with VSAM LSR Hiperspace
On Thu, 3 Aug 2006 12:00:27 -0500, Brian Peterson [EMAIL PROTECTED] wrote: The APAR text mentions IMS as being exposed. The defect, however, is within VSAM. I do not know if other VSAM LSR exploiters (such as CICS) are affected. I have asked that question. That APAR says this (at least it does now): === The problem only affects IMS applications using IRLM Notify that have hiperspace buffers in the LSR pool. It does not affect those IMS users of cross invalidate using the coupling facility. IMS is the only user of this function. No other VSAM users are affected. === Mark -- Mark Zelden Sr. Software and Systems Architect - z/OS Team Lead Zurich North America / Farmers Insurance Group mailto: [EMAIL PROTECTED] z/OS and OS390 expert at http://searchDataCenter.com/ateExperts/ Mark's MVS Utilities: http://home.flash.net/~mzelden/mvsutil.html -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Heads Up: OA17292 Data Loss with VSAM LSR Hiperspace
Here is the text from IBMLINK APAR Identifier .. OA17292 Last Changed 06/08/03 HIPERSPACE BUFFERS ARE NOT INVALIDATED AFTER IMS NOTIFY Symptom .. IN INCORROUT Status ... OPEN Severity ... 1 Date Closed . Component .. 5695DF106 Duplicate of Reported Release . 1K0 Fixed Release Component Name DFSMS VSAM MEDA Special Notice HIPER Current Target Date ..06/08/02 Flags SCP ... Platform PERVASIVE DATALOSS Status Detail: DESIGN/CODE - APAR solution is being designed and coded. PE PTF List: PTF List: Tentative Affected Releases and Current Relief Available: Release 1K0 : Relief is available in the form of: AA17292 Parent APAR: Child APAR list: ERROR DESCRIPTION: IMS issues a macro interface to VSAM to invalidate a particular buffer in the LSR buffer pool. If the buffer resides in a hiperspace buffer, it is not invalidated and can lead to lost updates if that address space later uses that downlevel copy of the buffer. The external symptoms can be 'pointer checker' errors, ABENU0852 and ABEND0849. The problem only affects IMS applications using IRLM Notify that have hiperspace buffers in the LSR pool. It does not affect those IMS users of cross invalidate using the coupling facility. IMS is the only user of this function. No other VSAM users are affected. ADDITIONAL SYMPTOMS: ABEND0C4 in IDA019XV msgDFS629I PSW AT ERROR = 077C2000 82D79960 SYS1 msgDFS629I MODID = UNKNOWN EPA = UNKNOWN SYS1 LOCAL FIX: Remove hiperspace buffers from the LSR pool definition. To do this, look in the IMS startup parms under DFSVSAMP DD or the DFSVSMxx member.Remove any HSO,HSR, HSn subparms from VSRBF= control statments. Dave Jousma Principal Systems Programmer [EMAIL PROTECTED] 616.653.8429 -Original Message- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Chase, John Sent: Thursday, August 03, 2006 2:52 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: Heads Up: OA17292 Data Loss with VSAM LSR Hiperspace Did that answer originate from DFSMS support? or CICS Support? -jc- This e-mail transmission contains information that is confidential and may be privileged. It is intended only for the addressee(s) named above. If you receive this e-mail in error, please do not read, copy or disseminate it in any manner. If you are not the intended recipient, any disclosure, copying, distribution or use of the contents of this information is prohibited. Please reply to the message immediately by informing the sender that the message was misdirected. After replying, please erase it from your computer system. Your assistance in correcting this error is appreciated. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
