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CA Mainframe Application Tuner provides additional information for IMS batch programs. IMS batch operates entirely in a single address space. Database operations are controlled by IMS routines using a VSAM local shared resource pool. Use the following steps to access statistics on the use of this pool.
The PoolView panel displays:
CA MAT ------------------- PoolView ------------------- ROW 1 TO 1 OF 1 COMMAND ===> SCROLL ===> CSR Line Commands: S - Select Profile: IMS Options: NORMAL LC Type Group Category ____ _____ _____________________________________ ------------------------------------------------------------------------------- __ IMS LSR IMS VSAM local pools
PoolView lists the shared pools that are used in the batch job.
The fields in PoolView are decribed next.
Type of pool, either IMS or VSAM.
Defines the group as LSR, or GSR.
LSR refers to VSAM Local Shared Resources where the buffer pool is maintained in the user's storage (PRIVATE). GSR refers to VSAM Global Shared Resources where the buffer pool is maintained in common storage (ECSA).
Literal name of the pool.
CA MAT ------------------------ Shared Pools ---------------- ROW 1 to 4 of 4 COMMAND ===> SCROLL ===> CSR Pool type: LOCAL Profile: IMS Total pool size: 59392 Options: NORMAL Hit ratio for all subpools: 88.1% Line commands: S - Select, D - Datasets No. of Buffer Buffer Requests Requests Hit Non-user LC Type Group SP Buffers size fixed w/read wo/read Ratio writes ____ _____ ___ _______ ______ ______ _________ _________ _____ _________ >------------------------------------------------------------------------------ __ IMS LSR 0 4 512 NO 0 158 100 % 0 __ IMS LSR 0 4 2,048 NO 69 225 76.5% 34 __ IMS LSR 0 4 4,096 NO 0 0 N/A 0 __ IMS LSR 0 4 8,192 NO 4 158 97.5% 0
The fields on the Shared Pools panel are decribed next.
LOCAL or GLOBAL
Local pools are used exclusively for IMS batch jobs and are located in the batch region. GLOBAL pools are located in CSA.
Total size of all the allocated buffers for all the buffer pools for this shared pool.
Measure of buffer pool performance.
A high hit ratio means that a high percentage of reads were satisfied from the buffer pools without having to access external media. The hit ratio is calculated as follows:
100 x (Retrieves wo/read / (retrieves w/read + retrieves wo/read))
Type of pool, VSAM or IMS.
Location of the subpool. LSR is in the user region; GSR is in CSA.
Identifier of the subpool.
Number of virtual buffers for this subpool.
Size in bytes of each buffer residing in this subpool.
Indicates whether the buffers are fixed in storage for this buffer pool.
Number of retrieves that were satisfied with an access to external media.
Number of retrieves that were satisfied from within the buffers in the pool. No I/O was necessary.
Percentage of the monitored period that READ requests were satisfied without a physical I/O.
Writes initiated by VSAM to make free space in this pool. These types of writes are very expensive and indicate that the pool might be too small. They are also called VSAM steal writes. Scroll right to display the following fields:
Writes by VSAM initiated by the user for synchronization processing.
Number of retrieves by relative byte address (RBA).
Number of inserts to the Entry Sequenced Data Set (ESDS).
Number of retrieves by key to a Key Sequenced Data Set (KSDS).
Number of inserts to a Key Sequenced Data Set (KSDS).
Number of times a buffer was altered by VSAM.
Number of VSAM GET requests.
Number of VSAM search buffer requests.
Number of Placeholders (PLH) in lock chain.
Current number of error buffers in pool.
Largest number of error buffers ever in the pool since the pool was created.
From the Shared Pools panel, you can display further detail by using one of the line commands:
VSAM Pool Details displays the same information as shown in Shared Pools, but in a detail format.
CA MAT -------------------------- VSAM Pool Details --------------------- COMMAND ===> Pool type: IMS Profile: IMS Pool group: LSR Pool ID: 0 Number of buffers: 4 Buffer size: 512 Placeholders in chain: 0 Hit Ratio: 100 % Requests requiring a read: 0 Requests satisfied from pool: 158 User initiated writes: 0 Non-user initiated writes: 0 Retrieves by RBA: 0 ESDS inserts: 0 Retrieves by key: 0 KSDS inserts: 0 Buffer alters: 0 VSAM GETS: 0 Buffer searches: 0 Error buffers in pool: 0 Maximum error buffers: 0
CA MAT ------------------ Pooled Data Sets ----------------- ROW 1 to 1 of 1 COMMAND ===> SCROLL ===> CSR Subpool: 0 BufferSize: 512 Profile: IMS Line commands: S - Select LC DDname Data Set Name Type Comp CISize ________ ____________________________________________ ____ ________ ______ ------------------------------------------------------------------------------- __ INVINDX CAMAT.TEST.INVINDX.DATA KSDS DATA 512
The fields on the Pooled Data Sets panel are described next.
Identification number of the VSAM subpool.
sSze in bytes of each buffer in the subpool.
DDNAME used to allocate the data set.
Full name of the data set.
One of the following VSAM data set types:
KSDS - a key sequenced data set that is always accompanied by an INDEX component. The index component does not have to use the same subpool.
ESDS - an entry sequenced data set
One of the following types:
Control Interval Size. The unit of transfer for VSAM data to and from storage. It is always a multiple of 512 bytes.
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