DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

Storage heading Description
24 BIT LOW PRIVATE Amount of private MVS storage below the 16 MB line. This storage is
obtained from bottom upward, usually for unauthorized programs
24 BIT HIGH PRIVATE Amount of private MVS storage below 16 MB line. This storage is
obtained from top downward, usually for authorized programs
31 BIT EXTENDED LOW PRIVATE Amount of private MVS storage above 16 MB line. This storage is
obtained from bottom upward, usually for unauthorized programs
31 BIT EXTENDED HIGH PRIVATE Amount of private MVS storage above 16 MB line. This storage is
obtained from top downward, usually for authorized programs
EXTENDED REGION SIZE (MAX) Maximum amount of MVS private storage available above the 16 MB
line
EXTENDED CSA SIZE The size of the common storage area (ECSA) above the 16 MB line
AVERAGE THREAD FOOTPRINT The current average memory usage of active user threads.
Derived as (TOTAL VARIABLE STORAGE - TOTAL AGENT SYSTEM
STORAGE) / (ALLIED THREADS + DBATS)
MAX NUMBER OF POSSIBLE THREADS The maximum number of possible threads dependent on storage size
and average thread footprint
Table B-2 summarizes all of the storage areas above the 2 GB bar.
Table B-2 DBM1 STORAGE ABOVE 2 GB
Storage heading Description
FIXED STORAGE Total amount of long-term page fixed storage
GETMAINED STORAGE Total storage acquired by GETMAIN macro. This includes space for
buffer pools, EDM pool, compression dictionaries and castout buffers
COMPRESSION DICTIONARY Total storage for compression dictionaries
CACHED DYNAMIC SQL STATEMENTS
(MAX)
Table B-3 describes the amount of real and auxiliary storage in use.
396 DB2 UDB for z/OS Version 8 Performance Topics
Maximum size of the dynamic statement cache. Since it can be
increased and decreased dynamically using SET SYSPARM, this is its
maximum value.
DBD CACHE (MAX) Maximum size of the DBD cache. Since it can be increased and
decreased dynamically using SET SYSPARM, this is its maximum
value.
VARIABLE STORAGE Amount of variable storage
VIRTUAL BUFFER POOLS Total storage allocated for buffer pools
VIRTUAL POOL CONTROL BLOCKS Total storage allocated for buffer pool control blocks
CASTOUT BUFFERS Total storage used for castout buffers in data sharing
STAR JOIN MEMORY POOL Total storage used for star join cache for data and keys