IBM DB2 Configuration Parameters
The following table lists key IBM DB2 configuration parameters, the recommended values at which to set them, and where they are maintained.
| Parameter | Description | Recommended value | Maintained using |
|---|---|---|---|
APPLHEAPSZ
|
Note: Increase the value of this parameter if your applications
receive an error indicating that there is not enough storage in the
application heap.
The Application Heap Size parameter defines the number of private memory pages available for use by the database manager on behalf of a specific agent or subagent. The heap is allocated when an agent or subagent is initialized for an application. The amount allocated is the minimum needed to process the request. As the agent or subagent requires more heap space to process larger SQL statements, the database manager needs to consider allocating additional memory up to the maximum specified by this parameter. |
512 |
$ db2 update db cfg for DatabaseName using APPLHEAPSZ 512
|
LOCKLIST
|
The LOCKLIST parameter indicates the amount
of storage that is allocated to the lock list. There is one lock list
per database and it contains the locks held by all applications concurrently
connected to the database. Locking is the mechanism that the database
manager uses to control concurrent access to data in the database
by multiple applications. Both rows and tables can be locked.
|
1500 |
$ db2 update db cfg for DatabaseName using LOCKLIST 1500
|
DBHEAP
|
There is one database heap per database, and the database manager uses it on behalf of all applications connected to the database. It contains control block information for tables, indexes, table spaces, and buffer pools, as well as for the event monitor buffers, log buffer, and catalog cache. Increase the value of this parameter if your applications receive an error indicating that there is not enough storage available in the database heap to process a statement. | 2000 |
$ db2 update db cfg for DatabaseName using DBHEAP 2000
|
DB2_RR_TO_RS
|
When the DB2_RR_TO_RS parameter is set to YES, the RR isolation level is downgraded to RS for user tables. RR semantics are no longer provided in the database manager instance. If your application does not require RR semantics, this registry variable can be used to reduce the next-key lock contention problems that can sometimes occur under RR. | YES | db2set command |
Tablespaces
|
This parameter allows you to select whether to have the database automatically handle configuration settings or if these will be manually administered. | Managed by Database |
CREATE DATABASE DatabaseName
|