LSR pools report
The LSR pools report is produced using the EXEC CICS EXTRACT STATISTICS LSRPOOL command. The statistics data is mapped by the DFHA08DS DSECT.
If you have combined data and index buffers, the report presents the statistics for data buffers and index buffers together as “Data and Index Buffer Statistics”. If you have separate data and index buffers, the report presents the statistics separately, as “Data Buffer Statistics” and “Index Buffer Statistics”.
| Field Heading | Description |
|---|---|
| Pool Number | The identifying number of the LSR pool. This value must be in the range 1 - 255. |
| Time Created | The time when this LSR pool was created.
Source field: A08LBKCD |
| Maximum key length | The length of the largest key of
a VSAM data set that can use this LSR pool. Source field: A08BKKYL |
| Total number of strings | The total number of VSAM strings
defined for this LSR pool. Source field: A08BKSTN |
| Peak concurrently active strings | The maximum number of strings that
were active during CICS® execution. If you have coded
a value for the number of strings the pool is to use, this statistic
is always less than or equal to the value you have coded. If your
coded value for string numbers is consistently higher than this value
in the statistics, you could consider reducing it so that your pool
of VSAM strings is not bigger than you need. Source field: A08BKHAS |
| Total requests waited for strings | The number of requests that were
queued because all the strings in the pool were in use. This number
reflects the number of requests that were delayed during CICS execution due to a restriction in LSR pool string resources.
Source field: A08BKTSW |
| Peak requests waited for strings | The highest number of requests that
were queued at one time because all the strings in the pool were in
use. Source field: A08BKHSW |
| Data Buffers | The number of data buffers specified
for the LSR pool. Source field: A08TDBFN |
| Hiperspace Data Buffers | The number of Hiperspace data buffers specified for the LSR pool. Source field: A08TDHBW |
| Successful look asides | The number of successful lookasides
to data buffers for this LSR pool. Source field: A08TDBFF |
| Buffer reads | The number of read I/O operations
to the data buffers for this LSR pool. Source field: A08TDFRD |
| User initiated writes | The number of user-initiated I/O
writes from the data buffers for this LSR pool. Source field: A08TDUIW |
| Non-user initiated writes | The number of non-user-initiated
I/O writes from the data buffers for this LSR pool. Source field: A08TDNUW |
| Successful Hiperspace CREADS | The number of successful CREAD requests
issued to transfer data from Hiperspace data buffers to
virtual data buffers. Source field: A08TDCRS |
| Successful Hiperspace CWRITES | The number of successful CWRITE requests
issued to transfer data from virtual data buffers to Hiperspace data buffers. Source field: A08TDCWS |
| Failing Hiperspace CREADS | The number of CREAD requests that
failed. MVS™ had withdrawn the space and VSAM had to read
data from DASD. Source field: A08TDCRF |
| Failing Hiperspace CWRITES | The number of CWRITE requests that
failed. There was insufficient Hiperspace and VSAM had to write the data to DASD. Source field: A08TDCWF |
| Index Buffers | The number of index buffers specified
for the LSR pool. Source field: A08TIBFN |
| Hiperspace Index Buffers | The number of Hiperspace index buffers specified for the LSR pool. Source field: A08TIHBW |
| Successful look asides | The number of successful lookasides
to index buffers for this LSR pool. Source field: A08TIBFF |
| Buffer reads | The number of read I/Os to the index
buffers for this LSR pool. Source field: A08TIFRD |
| User initiated writes | The number of user-initiated buffer
writes from the index buffers for this LSR pool. Source field: A08TIUIW |
| Non-user initiated writes | The number of non-user-initiated
buffer writes from the index buffers for this LSR pool. Source field: A08TINUW |
| Successful Hiperspace CREADS | The number of successful CREAD requests
issued to transfer data from Hiperspace index buffers to
virtual index buffers. Source field: A08TICRS |
| Successful Hiperspace CWRITES | The number of successful CWRITE requests
issued to transfer data from virtual index buffers to Hiperspace index buffers. Source field: A08TICWS |
| Failing Hiperspace CREADS | The number of CREAD requests that
failed. MVS had withdrawn the space and VSAM had to read
index data from DASD. Source field: A08TICRF |
| Failing Hiperspace CWRITES | The number of CWRITE requests that
failed. There was insufficient Hiperspace and VSAM had to write the index data to DASD. Source field: A08TICWF |
| Buffer Size | The size of the data buffers that
are available to CICS. Source field: A08BKBSZ |
| No. of Buffers | The number of buffers of each size
available to CICS. Source field: A08BKBFN |
| Hiperspace Buffers | The number of Hiperspace buffers specified for the pool. Source field: A08BKHBN |
| Look Asides | The number of read requests that
VSAM was able to satisfy without initiating an I/O operation; that
is, the requested record, whether index or data, was already present
in one of the buffer resident CIs. This means that no physical I/O
had to be done to put the control interval in the buffer. The tuning methodology usually employed involves either increasing the number of buffers of a particular CI size until the ratio of lookasides to READs stops increasing significantly or, conversely, reducing the number of buffers until the ratio of lookasides to READs begins to drop significantly. For most data sets, successful lookaside hits on indexes are more likely. These statistics are obtained from VSAM and represent the activity after the pool was created. Source field: A08BKBFF |
| Buffer Reads | The number of I/O operations to the
buffers that VSAM was required to initiate to satisfy the CICS application's activity. This figure represents failures
to find the control interval in the buffers. These statistics are obtained from VSAM and represent the activity after the pool was created. Source field: A08BKFRD |
| User Writes | The number of user-initiated I/O
WRITE operations from the buffers that VSAM was required to initiate
to satisfy the CICS application's activity. These statistics are obtained from VSAM and represent the activity after the pool was created. Source field: A08BKUIW |
| Non-User Writes | The number of non-user-initiated
I/O WRITE operations from the buffers that VSAM was forced to initiate
due to no buffers being available for reading the contents of a CI.
These statistics are obtained from VSAM and represent the activity after the pool was created. Source field: A08BKNUW |
| Look-Aside Ratio | The ratio of buffer lookasides to buffer reads.
Source field: ((A08BKBFF / (A08BKBFF + A08BKFRD)) * 100) |
| Successful CREADS/ CWRITES | The number of successful CREAD requests
issued to transfer data from Hiperspace buffers to virtual
buffers, and of successful CWRITE requests issued to transfer data
from virtual buffers to Hiperspace buffers. Source field: A08BKCRS + A08BKCWS |
| Failing CREADS/ CWRITES | The number of CREAD requests that
failed (because MVS had withdrawn the space and VSAM had to read
data from DASD), and the number of CWRITE requests that failed (because
there was insufficient Hiperspace and VSAM had to
write the data to DASD). Source field: A08BKCRF + A08BKCWF |
| Buffer Size | The size of the index data buffers
that are available to CICS. Source field: A08IKBSZ |
| No. of Buffers | The number of buffers of each size
available to CICS. Source field: A08IKBFN |
| Hiperspace Buffers | The number of Hiperspace buffers specified for the pool. Source field: A08IKHBN |
| Look Asides | The number of read requests that
VSAM was able to satisfy without initiating an I/O operation; that
is, the requested index record was already present in one of the buffer
resident CIs. This means that no physical I/O had to be done to put
the control interval in the buffer. The tuning methodology usually employed involves either increasing the number of buffers of a particular CI size until the ratio of lookasides to READs stops increasing significantly or, conversely, reducing the number of buffers until the ratio of lookasides to READs begins to drop significantly. For most data sets, successful lookaside hits on indexes are more likely. These statistics are obtained from VSAM and represent the activity after the pool was created. Source field: A08IKBFF |
| Buffer Reads | The number of I/O operations to the
buffers that VSAM was required to initiate to satisfy the CICS application's activity. This figure represents failures
to find the control interval in the buffers. These statistics are obtained from VSAM and represent the activity after the pool was created. Source field: A08IKFRD |
| User Writes | The number of user-initiated I/O
WRITE operations from the buffers that VSAM was required to initiate
to satisfy the CICS application's activity. These statistics are obtained from VSAM and represent the activity after the pool was created. Source field: A08IKUIW |
| Non-User Writes | The number of non-user initiated
I/O WRITE operations from the buffers that VSAM was forced to initiate
due to no buffers being available for reading the contents of a CI.
These statistics are obtained from VSAM and represent the activity after the pool was created. Source field: A08IKNUW |
| Look-Aside Ratio | The ratio of buffer look asides to buffer reads. Source field: ((A08BKBFF / (A08BKBFF + A08BKFRD)) * 100) |
| Successful CREADS/ CWRITES | The number of successful CREAD requests
issued to transfer data from Hiperspace buffers to virtual
buffers, and of successful CWRITE requests issued to transfer data
from virtual buffers to Hiperspace buffers. Source field: A08IKCRS + A08IKCWS |
| Failing CREADS/ CWRITES | The number of CREAD requests that
failed (because MVS had withdrawn the space and VSAM had to read
data from DASD), and the number of CWRITE requests that failed (because
there was insufficient Hiperspace and VSAM had to
write the data to DASD). Source field: A08IKCRF + A08IKCWF |