-DISPLAY BUFFERPOOL (DB2)

The DB2® command DISPLAY BUFFERPOOL displays the current status for one or more active or inactive buffer pools.

Abbreviation: -DIS BPOOL

Environment

This command can be issued from a z/OS® console, a DSN session under TSO, a DB2I panel (DB2 COMMANDS), an IMS™ or CICS® terminal, or a program using the instrumentation facility interface (IFI).

Data sharing scope: Member

Authorization

To execute this command, you must use a privilege set of the process that includes one of the following privileges or authorities:

DISPLAY system privilege
System DBADM authority
SYSOPR authority
SYSCTRL authority
SYSADM authority

DB2 commands that are issued from a logged-on z/OS console or TSO SDSF can be checked by DB2 authorization using primary and secondary authorization IDs.

Syntax

                       .-ACTIVE-----.     
>>-DISPLAY BUFFERPOOL(-+-*----------+-)------------------------->
                       | .-,------. |     
                       | V        | |     
                       '---bpname-+-'     

>--+------------------------+--+--------------------+----------->
   |         .-INTERVAL-.   |  |       .-ACTIVE-.   |   
   '-DETAIL(-+----------+-)-'  '-LIST(-+--------+-)-'   
             '-*--------'              '-*------'       

>--+----------------------+------------------------------------->
   |         .-ACTIVE-.   |   
   '-LSTATS(-+--------+-)-'   
             '-*------'       

>--+--------------------------------------+--------------------->
   |          .-*---------------------.   |   
   |          | .-,-----------------. |   |   
   |          | V                   | |   |   
   '-DBNAME-(-+---+-database-name-+-+-+-)-'   
                  +-name1:name2---+           
                  '-name*---------'           

>--+-------------------------------------+---------------------->
   |           .-*-------------------.   |   
   |           | .-,---------------. |   |   
   |           | V                 | |   |   
   '-SPACENAM(-+---+-space-name--+-+-+-)-'   
                   +-name1:name2-+           
                   '-name*-------'           

>--+-------------------+--+---------------------+--------------><
   '-GBPDEP(-+-YES-+-)-'  '-CASTOWNR(-+-YES-+-)-'   
             '-NO--'                  '-NO--'

Option descriptions

(ACTIVE)

Displays the current buffer pool status for all active buffer pools.

(*)

Displays the current buffer pool status for all active or inactive buffer pools.

(bpname)

Names the buffer pool for which current status is to be displayed.

4-KB page buffer pools are named BP0 through BP49
8-KB page buffer pools are named BP8K0 through BP8K9
16-KB page buffer pools are named BP16K0 through BP16K9
32-KB page buffer pools are named BP32K through BP32K9

DETAIL

Produces a detail report for one or more buffer pools. If DETAIL is not specified, a summary report is produced.

(INTERVAL): Requests statistics accumulated since the last incremental display, or since the buffer pool was first activated if no previous incremental display exists.
(*): Requests statistics accumulated since the buffer pool was first activated.

LIST

Lists the open index spaces and table spaces associated with the buffer pools included in the report. Basic information is provided for non-data-sharing systems while more detail is provided if data sharing is active.

(ACTIVE): Restricts the list of open index spaces and table spaces to those that are currently in use.
(*): Requests a list of all open index spaces and table spaces, whether currently in use or not.

LSTATS

Lists data set statistics for the open index spaces and table spaces associated with the buffer pools included in the report. The statistics displayed are incremental since the last time they were displayed.

(ACTIVE): Restricts the list statistics to those data sets that are currently in use.
The default is ACTIVE when LIST is not specified or if LIST is specified with no parameter. If LIST is specified with a parameter and LSTATS has no parameter, the parameter specified for LIST is used for LSTATS.
(*): Includes statistics for all open index spaces and table spaces, whether currently in use or not.

DBNAME

Specifies which databases are included in the LIST display and the LSTATS display. If you specify DBNAME without LIST, LIST(ACTIVE) is assumed.

Abbreviation: DBN

(database-name, ...)

Identifies one or more databases to be included in the LIST and LSTATS displays. database-name can have any of the forms in the following list. In the list, name1 and name2 represent strings of one- to eight-characters. name represents a string of one- to eight-characters.

Form: Displays the status of...
name1: The database name1
name1:name2: All databases with names from name1 to name2 in a sorted list of database names.
name*: All databases whose names begin with the string name

(*)

Displays information on all databases that match the LIST specification. This is the default.

SPACENAM

Specifies which table spaces or index spaces within the specified databases to include in the LIST display and the LSTATS display. If you use SPACENAM without DBNAME, DBNAME(*) is assumed.

Abbreviation: SPACE

(*)

Displays information about all table spaces and index spaces of the specified databases. This is the default.

(space-name, ...)

Identifies one or more spaces to be included in the LIST and LSTATS displays. You can write space-name like database-name to designate:

The name of a single table space or index space
A range of names
A partial name followed by a pattern-matching character

GBPDEP

Indicates whether to restrict the list of data sets to those that are group buffer pool dependent. This option is not valid if this is a non-data sharing DB2.

(YES)

Restricts the list of page sets to those that are group buffer pool dependent (GBP-dependent). An index space or table space is GBP-dependent if either of these conditions are true:

Inter-DB2 R/W interest exists in it.
Changed pages from it exist in the group buffer pool that have not yet been written to disk.

(NO)

Restricts the list of page sets to those that are non-group buffer pool dependent.

CASTOWNR

Indicates whether to restrict the list of data sets to those for which this DB2 member is the castout owner. This option is not valid if this is a non-data sharing DB2.

(YES): Restricts the list of page sets for which this DB2 member is the castout owner.
(NO): Restricts the list of page sets for which this DB2 member is not the castout owner.

Output

Message DSNB401I indicates the beginning of the output of the command.

Examples

Example: Displaying a summary buffer pool report

A summary report is the default report if the DETAIL option is not specified. The following example shows a summary report that can be produced by the command:

-DISPLAY BUFFERPOOL(BP0) LIST(*) DBNAME(DSN8*)

The output is similar to this output:

DSNB401I - BUFFERPOOL NAME BP0, BUFFERPOOL ID 0, USE COUNT 20
DSNB402I - BUFFERPOOL SIZE = 3000 BUFFERS   AUTOSIZE = YES
             ALLOCATED      = 3000        TO BE DELETED    = 0
             IN-USE/UPDATED =    0
             BUFFERS ACTIVE              = 3000
DSNB406I -   PGFIX ATTRIBUTE -
             CURRENT                   = NO
             PENDING                   = YES
             PAGE STEALING METHOD      = LRU
DSNB404I - THRESHOLDS - 
             VP SEQUENTIAL             = 80 
             DEFERRED WRITE            = 85 
             VERTICAL DEFERRED WRT     = 80, 0
             PARALLEL SEQUENTIAL       = 50 
             ASSISTING PARALLEL SEQT   = 0
DSN9022I - DSNB1CMD '-DISPLAY BUFFERPOOL' NORMAL COMPLETION

Example: Displaying a detailed buffer pool report

A detail report can be generated that includes all summary report information and additional buffer pool related statistics. The following example shows a detail report that can be produced by the command:

-DISPLAY BUFFERPOOL(BP0) DETAIL

The output looks similar to this output:

DSNB401I - BUFFERPOOL NAME BP0, BUFFERPOOL ID 0, USE COUNT 10
DSNB402I - BUFFERPOOL SIZE = 3000 BUFFERS   AUTOSIZE = YES
            ALLOCATED      = 3000        TO BE DELETED    = 0
            IN-USE/UPDATED   = 200
            BUFFERS ACTIVE   = 3000
DSNB406I -   PGFIX ATTRIBUTE -
             CURRENT                   = NO
             PENDING                   = YES
             PAGE STEALING METHOD      = LRU
DSNB404I - THRESHOLDS -
             VP SEQUENTIAL             = 80
             DEFERRED WRITE            = 50
             VERTICAL DEFERRED WRT     = 10, 0
             PARALLEL SEQUENTIAL       = 50
             ASSISTING PARALLEL SEQT   =  0
 
DSNB409I - INCREMENTAL STATISTICS SINCE 10:32:48 OCT 23, 1993
 
DSNB411I - RANDOM GETPAGE    =      230 SYNC READ I/O (R) =      180
           SEQ.   GETPAGE    =      610 SYNC READ I/O (S) =       20
           DMTH HIT          =        0 PAGE-INS REQ      =       40
           SEQUENTIAL        =      200 VPSEQT HIT        =        0
           RECLASSIFY        =        0 
 
DSNB412I - SEQUENTIAL PREFETCH -
             REQUESTS        =        0   PREFETCH  I/O   =        0
             PAGES READ      =        0
 
DSNB413I - LIST PREFETCH -
             REQUESTS        =        0   PREFETCH  I/O   =        0
             PAGES READ      =        0
 
DSNB414I - DYNAMIC PREFETCH -
             REQUESTS        =        0   PREFETCH  I/O   =        0
             PAGES READ      =        0
 
DSNB415I - PREFETCH DISABLED -
             NO BUFFER       =        0   NO READ ENGINE  =           0
DSNB420I - SYS PAGE UPDATES  =        0 SYS PAGES WRITTEN =           0
           ASYNC WRITE I/O   =        0 SYNC WRITE I/O    =           0
           PAGE-INS REQ      =        0
DSNB421I - DWT HIT           =        0 VERTICAL DWT HIT  =           0
DSNB440I - PARALLEL ACTIVITY -
             PARALL REQUEST  =        0   DEGRADED PARALL =       0
DSN9022I - DSNB1CMD '-DISPLAY BUFFERPOOL' NORMAL COMPLETION

Example: Listing open table spaces and index spaces that are associated with a buffer pool

With the summary or detail report, you can list open table spaces and index spaces associated with the buffer pool. You can also request a display of statistics for each listed table space and index space. An example of a report generating this information could be produced by the command:

-DISPLAY BUFFERPOOL(BP0) LIST LSTATS

The output looks similar to this output:

DSNB401I - BUFFERPOOL NAME BP0, BUFFERPOOL ID 0, USE COUNT 3
DSNB402I - BUFFERPOOL SIZE = 3000 BUFFERS   AUTOSIZE = YES
            ALLOCATED      = 3000        TO BE DELETED    = 0
            IN-USE/UPDATED   = 200
            BUFFERS ACTIVE   = 3000
DSNB406I -   PGFIX ATTRIBUTE -
             CURRENT                   = NO
             PENDING                   = YES
             PAGE STEALING METHOD      = LRU
DSNB404I - THRESHOLDS -
             VP SEQUENTIAL         = 80   
             DEFERRED WRITE        = 50   
             VERTICAL DEFERRED WRT = 10, 0
             PARALLEL SEQUENTIAL   = 50
             ASSISTING PARALLEL SEQT = 0
DSNB455I - SYNCHRONOUS I/O DELAYS -
             AVERAGE DELAY         = 22
             MAXIMUM DELAY         = 35
             TOTAL PAGES           = 23
DSN9022I - DSNB1CMD '-DISPLAY BUFFERPOOL' NORMAL COMPLETION