DBM1 and MVS Storage Below 2 GB
This topic shows detailed information about "Statistics - DBM1 and MVS Storage Below 2 GB".
This 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
The field labels shown in the following sample layout of "Statistics - DBM1 and MVS Storage Below 2 GB" are described in the following section.
DBM1 AND MVS STORAGE BELOW 2 GB QUANTITY
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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 - 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