Buffer pool detail report
The buffer pool report provides information about the movement of database pages between the DASD and the main storage buffers. It presents information about the number of read and write operations, the amount of read and write requests, and the average wait times.
The following command produces the report shown below:
IOACTIVITY
REPORT
LEVEL(BUFFER)
1 LOCATION: RS22ODS5 IBM Z OMEGAMON AI FOR DB2 (V6R1M0) PAGE: 1-1 GROUP: ODS5 I/O ACTIVITY REPORT - BUFFER POOL REQUESTED FROM: NOT SPECIFIED MEMBER: OCA5 TO: NOT SPECIFIED SUBSYSTEM: OCA5 ORDER: PRIMAUTH-PLANNAME-BPID INTERVAL FROM: 02/28/19 11:20:21.31 DB2 VERSION: V12 TO: 02/28/19 11:21:58.70 0PRIMAUTH -- I/O REQUEST --- ---------------- READ REQUESTS ------------- ---------- WRITE REQUEST ----------- PLANNAME ------- WITH I/O ------- BPID PAGES/ W/OUT CAST PAGES/ DB TOTAL AET TOTAL TYPE AET % READ I/O % TOTAL TYPE OUT AET WRITE OPEN -------------------- -------- --------- -------- ----- --------- ------ ------ ------ -------- ----- ---- --------- ------ ---- 0SYSOPR 'BLANK' BP0 4 0.000331 2 SYNCH 0.000337 100.00 1.00 0.00 0 - N/C 0.00 0 2 DYNPF 0.000649 50.00 5.00 50.00 0TS5811 DSNREXX BP0 145802 0.000414 602 SYNCH 0.000132 100.00 1.00 0.00 0 - N/C 0.00 0 298 ZHYPL 0.000067 100.00 1.00 0.00 145200 SEQPF 0.000415 100.00 31.98 0.00 0 *** GRAND TOTAL *** 145806 0.000414 604 SYNCH 0.000132 100.00 1.00 0.00 0 - N/C 0.00 0 298 ZHPL 0.000067 100.00 1.00 0.00 145200 SEQPF 0.000415 100.00 31.98 0.00 2 DYNPF 0.000649 50.00 5.00 50.00 ---------------------------------------- ! PAGE ACTIVE UPDATED ! ! FAULTS BUFFERS PAGES ! ! ---------- ---------- ---------- ! ! 0 0 0 ! ---------------------------------------- 0I/O ACTIVITY REPORT COMPLETE
- OMEGAMON AI for Db2 Identifiers
- The buffer pool report presents data summarized by OMEGAMON AI for Db2 identifiers. The report can be ordered
by up to three OMEGAMON AI for Db2 identifiers.
The identifiers used to sort the report are printed in the leftmost column. They are printed
whenever they change. The second and third identifiers are indented to appear under the relevant
column subheading. Note: Blank or null OMEGAMON AI for Db2 identifiers are denoted by the word 'BLANK'.
- I/O REQUEST
-
- TOTAL
- The total number of I/O requests.
- AET
- The average elapsed time per I/O request.
- READ REQUESTS
-
- TOTAL
- The number of read I/O requests of a specific type.
Calculation: count of matching IFCID 006 and 007 record pairs of the same type
- TYPE
- The type of read request. The field can contain one of the following values:
- SYNCH
- Synchronous read request
- SEQPF
- Sequential prefetch requests (determined at bind time)
- DYNPF
- Dynamic prefetch request (triggered at run time by sequential detection logic)
- LSTPF
- List prefetch request
- ZHYPL
- Synchronous reads that used zHyperLink. This is a subset of the total synchronous reads.
If there are no read requests, a dash (—) is printed.
Derivation:- SYNCH
- Db2® field QW0006F equal to R
- SEQPF
- Db2 field QW0006F equal to S
- DYNPF
- Db2 field QW0006F equal to D
- LSTPF
- Db2 field QW0006F equal to L
- WITH I/O AET
- The average elapsed time for a read of a specific type.
- WITH I/O %
- The percentage of total read requests of a particular type that resulted in an I/O.
- WITH I/O PAGES/READ
- Pages read per successful read request of a particular type.
- W/OUT I/O %
- The percentage of total read requests of a particular type that did not result in an I/O. This can occur because all the pages requested by a prefetch read were already in the buffer pool.
- WRITE REQUEST
-
- TOTAL
- The number of write I/O requests of a specific type. Up to two lines are generated, depending on
the write type.
For synchronous writes: count of matching IFCID 008 and 009 record pairs
For asynchronous writes: count of matching IFCID 009 and 010 record pairs
- TYPE
- The type of write request. The field can contain one of the following values:
- SYNCH
- Synchronous write request
- ASYNC
- Asynchronous write request
- CASTOUT
- The number of synchronous and asynchronous writes due to coupling facility castouts. This field
contains one of the following values:
- YES
- The write operations were initiated due to a coupling facility castout.
- NO
- The write operations were initiated as a normal write I/O.
- AET
- The average elapsed time per write of a specific type.
- PAGES/WRITE
- The number of pages written per write of a specific type.
- DB OPEN
- The number of database open requests.
- PAGE FAULTS
- The number of anticipated page faults. Real storage frames are tested before issuing write.
- ACTIVE BUFFERS
- The number of active buffers in the pool.
- UPDATED PAGES
- The number of updated pages in the deferred write queue for the buffer pool that is identified in field QW0008BP or QW0010BP.
- SUBTOTAL
- When a report is ordered by three identifiers and there is more than one third-level identifier reported under it, a subtotal is printed each time the second-level identifier changes.
- TOTAL
- When a report is ordered by two or three identifiers and there is more than one second-level identifier reported under it, a total is printed each time the first-level identifier changes.
- GRAND TOTAL
- A grand total is printed at the end of each location if there is more than one first-level identifier reported.