In previous releases, the applheapsz database configuration
parameter referred to the amount of application memory each individual
database agent working for that application could consume. Starting
in Version 9.5, applheapsz refers to the total
amount of application memory that can be consumed by the entire application.
For
partitioned database environment, Concentrator, or SMP configurations,
this means that the applheapsz value used in previous
releases might need to be increased under similar workloads, unless
the AUTOMATIC setting is used.
With Version 9.5, this database configuration parameter
has a default value of AUTOMATIC, meaning that it
increases as needed until either the appl_memory limit
is reached, or the instance_memory limit is reached.
- Configuration type
- Database
- Parameter type
- Configurable online
- Default [range]
- Automatic [16 - 60 000]
Note: The default value is subject to change by the DB2® Configuration Advisor after
initial database creation.
- Unit of measure
- Pages (4 KB)
- When allocated
- When an application associates with, or connects to, a database.
- When freed
- When the application disassociates or disconnects from the database.
Note: This parameter defines the maximum size of the
application heap. One application heap is allocated per database application
when the application first connects with the database. The heap is
shared by all database agents working for that application. (In previous
releases, each database agent allocated its own application heap.)
Memory is allocated from the application heap as needed to process
the application, up to the limit specified by this parameter. When
set to
AUTOMATIC, the application heap is allowed
to grow as needed up to either the
appl_memory limit
for the database, or the
instance_memory limit
for the database partition. The entire application heap is freed when
the application disconnects with the database.
The online changed
value takes effect at an application connection boundary, that is,
after it is changed dynamically, currently connected applications
still use the old value, but all newly connected applications will
use the new value.
DB2 Version 9.7 for Linux, UNIX, and Windows