DBM1 and MVS Storage Below 2 GB

The DBM1 and MVS Storage Below 2 GB block shows information about storage allocation within the DBM1 address space. Storage quantities are shown in megabytes, this means that when you want to compare this with absolute values, as stored in the performance database, for example, you need to multiply the value shown by 1048576 (1024*1024). Similarly where a quantity is shown followed by a K, for example 262.1K, the quantity shown is 262.1MB*1000 (262.1*1048576*1000 bytes).

Statistics - DBM1 and MVS Storage Below 2 GB


DBM1 AND MVS STORAGE BELOW 2 GB                         QUANTITY    	 		
-------------------------------------------- 	------------------   
TOTAL DBM1 STORAGE BELOW 2 GB (MB)                            6.52    
 TOTAL GETMAINED STORAGE (MB)                                 0.52    
TOTAL VARIABLE STORAGE (MB)                                   1.11    
  TOTAL AGENT LOCAL STORAGE (MB)                              0.32    
   TOTAL AGENT SYSTEM STORAGE (MB)                            0.22    
     NUMBER OF PREFETCH ENGINES                               0.23    
     NUMBER OF DEFERRED WRITE ENGINES                         9.00    
     NUMBER OF CASTOUT ENGINES                                1.00    
     NUMBER OF GBP WRITE ENGINES                              7.00    
     NUMBER OF P-LOCK/NOTIFY EXIT ENGINES                     1.00    
  TOTAL AGENT NON-SYSTEM STORAGE (MB)                         2.00    
   TOTAL NUMBER OF ACTIVE USER THREADS                        0.10    
     NUMBER OF ALLIED THREADS                                 7.00    
     NUMBER OF ACTIVE DBATS                                   7.00    
     NUMBER OF POOLED DBATS                                   0.00    
   NUMBER OF PARALLEL CHILD THREADS                           0.00    
SYSTEM COPIES OF CACHED SQL STMTS (MB)                        0.00    
   IN USE STORAGE (MB)                                        7.00    
   HWM FOR ALLOCATED STATEMENTS (MB)                          1.00   
  SYSTEM COPIES OF STATIC SQL (MB)                            7.00    
    IN USE STORAGE (MB)                                       1.00    
  THREAD PLAN AND PACKAGE STORAGE (MB)                        2.00    
  BUFFER MANAGER STORAGE CNTL BLKS (MB)                       0.10    
 TOTAL FIXED STORAGE (MB)                                     7.00    
 TOTAL GETMAINED STACK STORAGE (MB)                           7.00    
   TOTAL STACK STORAGE IN USE (MB)                            6.52 
     SYSTEM AGENT STACK STORAGE IN USE (MB)                   0.52 
  STORAGE CUSHION (MB)                                        1.11 

DBM1 AND MVS STORAGE BELOW 2 GB   CONTINUED             QUANTITY
-------------------------------------------- 	------------------
 24 BIT LOW PRIVATE                      (MB)                 0.24
 24 BIT HIGH PRIVATE                     (MB)                 1.24
 24 BIT PRIVATE CURRENT HIGH ADDRESS              0000000000044000  
 31 BIT EXTENDED LOW PRIVATE             (MB)               165.86
 31 BIT EXTENDED HIGH PRIVATE            (MB)               315.38
 31 BIT PRIVATE CURRENT HIGH ADDRESS              000000003CA95000  
 EXTENDED REGION SIZE (MAX)              (MB)              1244.00
 EXTENDED CSA SIZE                       (MB)               632.12
                                                                 
 AVERAGE THREAD FOOTPRINT                (MB)                 0.18
 MAX NUMBER OF POSSIBLE THREADS                               4038
                                                                 
 AVERAGE THREAD FOOTPRINT (TYPE II)      (MB)                  N/A
 MAX NUMBER OF POSSIBLE THREADS (TYPE II)                      N/A

TOTAL DBM1 STORAGE BELOW 2 GB (MB)

Total DBM1 storage. This includes:

Fixed length storage use
Getmained storage
Save areas
Variables

Field Name: SW0225DB

TOTAL GETMAINED STORAGE (MB)

Total storage acquired by GETMAIN. This includes space for virtual pools, EDM pool, compression dictionary, castout buffers, and the data space lookaside buffer, and data space buffer pool control blocks.

This figure can be different from the sum of GETMAIN storage items shown in the statistics DBM1 storage, because Db2 does not produce grouping statistics for all GETMAIN storage.

Field Name: QW0225GM

TOTAL VARIABLE STORAGE (MB)

Total storage used by all variable pools. This includes storage used by:

System agents
Local agents
RID pool
Pipe manager subpool
Local dynamic statement cache control blocks
Local dynamic statement cache statement pool
Buffer and data manager trace tables
A list of objects in restricted state including the new PRO state. If consumption of this storage pool is high, review restrictive exception state of database objects and check whether they can be resolved or reduced.

Field Name: QW0225VR

TOTAL AGENT LOCAL STORAGE (MB)

The amount of storage allocated for agent-related local storage. This storage is used for operations such as sort.

Background and Tuning Information

Sorting requires a large amount of virtual storage because there can be multiple copies of the data being sorted at a given time.

Db2 Sort uses two kinds of storage pool for various internal control structures and data records, an agent-related local storage pool and a global sort pool. To take advantage of the 64-bit addressability for larger storage pool, some high level sort control structures are kept in agent-related storage below the 2 GB bar, which contain 64-bit pointers to areas in the global sort pool above the 2 GB bar. The sort pool above 2 GB contains sort tree nodes and data buffers.

Field Name: QW0225AL

TOTAL AGENT SYSTEM STORAGE (MB)

Storage used by system agents.

Field Name: QW0225AS

NUMBER OF PREFETCH ENGINES

Number of engines used for sequential, list, and dynamic prefetch.

Field Name: QW0225PF

NUMBER OF DEFERRED WRITE ENGINES

Number of engines used for deferred write operations.

Field Name: QW0225DW

NUMBER OF CASTOUT ENGINES

Number of engines available for data-sharing castout processing.

Field Name: QW0225CE

NUMBER OF GBP WRITE ENGINES

Number of engines for group buffer pool writes.

Field Name: QW0225GW

NUMBER OF P-LOCK/NOTIFY EXIT ENGINES

Number of data sharing P-Lock engines and Notify Exit engines.

Field Name: QW0225PL

TOTAL AGENT NON-SYSTEM STORAGE (MB)

Total Agent Non-System Storage. It is the difference between the Total Agent Local Storage (QW0225AL) and the Total Agent System Storage (QW0225AS).

Field Name: SW0225AN

TOTAL NUMBER OF ACTIVE USER THREADS

Total number of active user threads. This includes all active allied threads and the current number of active DBATs.

Field Name: SACUSTHR

NUMBER OF ALLIED THREADS

The number of active allied threads.

Field Name: QW0225AT

NUMBER OF ACTIVE DBATS

The number of active connections, or active and disconnected DBAT threads.

Field Name: SACDBATS

NUMBER OF POOLED DBATS

The current number of disconnected (pooled) DBATs that are available to process type 2 inactive or new connections.

Field Name: QDSTNADS

NUMBER OF PARALLEL CHILD THREADS

The number of active parallel child threads.

Field Name: QW0225PT

SYSTEM COPIES OF CACHED SQL STMTS (MB)

The total shareable storage allocated for dynamic SQL statements used by active threads.

For Db2 11, this field is derived from QW0225SC8 and related to storage above the bar.
Prior to Db2 11, this field is derived from QW0225SC and related to storage below the bar. The storage is used for executable code sequences (xPROC).

Field Name: SW0225SC

IN USE STORAGE (MB)

The total shareable storage requested for dynamic SQL statements used by active threads.

For Db2 11, this field is derived from QW0225LS8 and related to storage above the bar.
Prior to Db2 11, this field is derived from QW0225LS and related to storage below the bar. The storage is used for executable code sequences (xPROC).

Field Name: SW0225LS

HWM FOR ALLOCATED STATEMENTS (MB)

A statistics interval high-water mark of requested shareable storage for dynamic SQL statements used by active threads.

For Db2 11, this field is derived from QW0225HS8 and related to storage above the bar.
Prior to Db2 11, this field is derived from QW0225HS and related to storage below the bar. The storage is used for executable code sequences (xPROC).

Field Name: SW0225HS

SYSTEM COPIES OF STATIC SQL (MB)

The total shareable storage allocated for static SQL statements.

For Db2 11, this field is derived from QW0225SX8 and related to storage above the bar.
Prior to Db2 11, this field is derived from QW0225SX and used for storage of executable code sequences (xPROC) below the bar.

Field Name: SW0225SX

IN USE STORAGE (MB)

The total storage requested for shareable static SQL statements.

For Db2 11, this field is derived from QISEKSPA and related to storage above the bar.
Prior to Db2 11, this field is derived from QISEKSPA8 and used for storage of executable code sequences (xPROC) below the bar.

Field Name: SISEKSPA

THREAD PLAN AND PACKAGE STORAGE (MB)

The storage allocated to plans and packages below the bar.

Field Name: SISESQB

BUFFER MANAGER STORAGE CNTL BLKS (MB)

Storage used for page set control blocks.

Field Name: QW0225BB

TOTAL FIXED STORAGE (MB)

Total amount of fixed storage.

Field Name: QW0225FX

TOTAL GETMAINED STACK STORAGE (MB)

Total GETMAINED storage allocated for program stack use.

Field Name: QW0225GS

TOTAL STACK STORAGE IN USE (MB)

The amount of stack storage that is in use.

Field Name: QW0225SU

SYSTEM AGENT STACK STORAGE IN USE (MB)

The amount of 31-bit stack storage that is in use for system agents. This is a subset of QW0225SU.

Field Name: QW0225SS

STORAGE CUSHION (MB)

Storage reserved to allow Db2 to complete critical functions while short on storage. This includes the contract warning cushion, storage reserved for must-complete operations, and storage for MVS use.

Field Name: STORCUSH

24 BIT LOW PRIVATE

The amount of private MVS storage below the 16 MB line. This storage is obtained from bottom upward, usually for unauthorized programs.

Field Name: QW0225LO

24 BIT HIGH PRIVATE

The amount of private MVS storage below the 16 MB line. This storage is obtained from top downward, usually for authorized programs.

Field Name: QW0225HI

24 BIT PRIVATE CURRENT HIGH ADDRESS

The current high address of the 24-bit private region.

Field Name: QW0225TP

31 BIT PRIVATE CURRENT HIGH ADDRESS

The current high address of the 31-bit private region.

Field Name: QW0225EP

31 BIT EXTENDED LOW PRIVATE

The amount of private MVS storage above the 16 MB line. This storage is obtained from bottom upward, usually for unauthorized programs.

Field Name: QW0225EL

31 BIT EXTENDED HIGH PRIVATE

The amount of private MVS storage above the 16 MB line. This storage is obtained from top downward, usually for authorized programs.

Field Name: QW0225EH

EXTENDED CSA SIZE

The size of the common storage area (CSA) above the 16 MB line.

Field Name: QW0225EC

EXTENDED REGION SIZE (MAX)

The maximum amount of MVS private storage available above the 16 MB line.

Field Name: QW0225RG

AVERAGE THREAD FOOTPRINT

The current average memory usage of active user threads (allied threads and DBATs).

Field Name: SW0225TF

MAX NUMBER OF POSSIBLE THREADS

The maximum number of possible threads. This value is derived from the storage size and average memory usage of active user threads.

Field Name: SW0225MT

AVERAGE THREAD FOOTPRINT (TYPE II)

The current average memory usage of active allied threads and the maximum number of active DBATs that existed. The formula used for this value is suited for Enterprise Resource Planning (ERP) systems, such as SAP.

Field Name: SW0225TS

MAX NUMBER OF POSSIBLE THREADS (TYPE II)

The maximum number of possible threads. It depends on the storage size and average memory usage of active allied threads and the maximum number of active DBATs that existed.

Field Name: SW0225MS