Thread History Buffer Pool Activity

This panel provides information about buffer pool activity for a completed thread.


________________ ZHTBUF   VTM     O2       V540.#P SE12 11/06/13 13:54:31   2 
> Help PF1               Back PF3               Up PF7                 Down PF8
                                                                               
>          THREAD HISTORY:  Enter a selection letter on the top line.          
                                                                               
> A-THREAD DETAIL   B-LOCK COUNTS  C-LOCK WAITS     D-GLOBAL LOCKS  E-SORT/SCAN
> F-DYNAMIC SQL     G-SQL COUNTS   H-DISTRIBUTED    *-BUFFER POOL   J-GROUP BP 
> K-PACKAGE SUMMARY L-RES LIMIT    M-PARALLEL TASKS                            
===============================================================================
>                     THREAD HISTORY BUFFER POOL ACTIVITY                      
 HPLN                                                                          
+ Thread:  Plan=DISTSERV  Connid=SERVER   Corrid=db2bp.exe    Authid=MIS       
+ Attach:  DIST           DB2=SE12        MVS=PMO4                             
+ Dist  :  Type=DATABASE ACCESS, Luwid=G99D84D9.I2DD.131106113855              
+ Time  :  Start=11/06/2013 12:40:33.546188     End=11/06/2013 13:41:56.444510 
 buf                                                                           
+ Buffer Pool: BP0                                                             
+                                                                              
+ Getpage Requests       =    6790500   Failed Getpage Requests    =          0
+ Synchronous Read I/O   =          0   Getpage/Read I/O           =        .00
+ Page Updates           =          0   Seq Prefetch Requests      =          0
+ List Prefetch Requests =          0   Dynamic Prefetch Requests  =    1851955
+ Prefetch Pages Read    =          0                                          
+ Immediate Writes       =          0   BP Hit Percentage          =      72.7%
===============================================================================

Fields

Thread identifier: This information identifies the thread to which the information in this panel applies.

Plan: The Db2 plan name of the active thread.
Connid: The Db2 connection identifier of the active thread.
Corrid: The Db2 correlation identifier of the active thread. If the correlation is not set, N/A is displayed.
Authid: The Db2 authorization identifier of the active thread.
Attach: Depending on the type of connection, the appropriate information is displayed.; Attach information is displayed only if the thread is a distributed allied thread (not for distributed database access threads).

Attachment identifier:

Connection Type

The connection type is displayed in the first field:

APPLDIR: Application directed access (database access threads)
BATCH: Other Db2 batch threads
CALLATCH: Db2 call attach
CICS®: CICS attach
DLI: DL/I batch
IMSBMP: IMS attach BMP
IMSMPP: IMS attach MPP
IMSCTRL: IMS control region
IMSBMPB: IMS transaction BMP
RRSAF: Recoverable Resource Manager Services Attachment Facility
TSO: TSO foreground and background
Utility: Utility thread

Db2

The Db2 subsystem identifier.

MVS

The MVS system identifier.

ORIGAUTH

The original (primary) Db2 authorization identifier of the thread. This field displays only when the original identifier is different from the Authid.

Distributed thread identifier: The following fields are displayed if the thread has a distributed relationship with a remote Db2 subsystem.

Type

The distributed thread type.

Distributed Allied: A requesting thread; one that has issued an SQL call to a remote Db2 location.
Database Access: A responding thread; one that is serving a remote Db2 location by responding to an SQL call.

Db2=

The Db2 subsystem ID, indicating the member of the data sharing group of this thread.

Luwid

This value consists of two parts: the logical unit of work ID (luw-id) and a token. The token can be used in place of the luw-id in any Db2 command that accepts luw-id as input. Format:

luw-id=token

The luw-id consists of the network name, the originating VTAM® LUNAME, and a unique identifier (separated by periods). Thus, the Luwid field displays data like in the following example:

USCACO01.O2D22A.A1FE8E04B9D4=8

System

The originating Db2 job name and the resource manager that is the source of the thread. An additional line below the Attach line identifies the user thread, if any, being served by the system thread.

Time identifier:

Start: The start date and time of this thread execution.
End: The end date and time of this thread execution.

Buffer pool:

Getpage Requests: The number of thread Getpage requests. This value includes conditional, unconditional, successful, and unsuccessful requests. A Getpage request might not actually result in physical I/O if the requested page is in the buffer pool.
Failed Getpage Requests: The number of times a conditional Getpage request could not be satisfied. A conditional Getpage will not wait for a page that is not currently in the buffer pool. A conditional Getpage is used with parallel I/O processing only.
Synchronous Read I/O: The number of synchronous Read I/O requests issued by the thread.
Getpage/Read I/O: The ratio of Getpage requests to the number of synchronous Read I/O requests. This value does not include Prefetch requests.
Page Updates: The number of DB2 page updates made by the thread since thread creation. This value is incremented each time a row in a page is updated, not just once for each page updated. DB2 might update pages when it creates intermediate result tables because of a qualified SELECT statement, even though SELECT statements are generally thought of as read only operations. Pages that have been updated are written asynchronously by DB2, according to DB2's internal Deferred Write algorithm, not immediately after update or commit. DB2 resets the page update count at Create Thread and Signon. If Signon is not driven, the page update count is cumulative.
Seq Prefetch Requests: The number of Sequential Prefetch requests issued by the thread. Sequential Prefetch Read I/O is performed asynchronously to the user's request.
List Prefetch Requests: The number of List Prefetch requests issued by the thread.
Dynamic Prefetch Requests: The number of Dynamic Prefetch requests issued by the thread.
Prefetch Pages Read: The number of pages read asynchronously for Prefetch.
Immediate Writes: The number of immediate (synchronous) Write I/O requests issued for a thread.
BP Hit Percentage: The percentage of Getpage requests for which the data was already in the buffer pool.