You should consider the values of the following configuration parameters when you are setting up your environment:
The tm_database database manager configuration parameter identifies the name of the Transaction Manager (TM) database for each DB2 instance.
The spm_name database manager configuration parameter identifies the name of the SNA Sync Point Manager (SPM) instance to the database manager. It is defined in the system database directory and, if remote, in the node directory.
The resync_interval database manager configuration parameter identifies the time interval in seconds for which a Transaction Manager (TM), Resource Manager (RM), or Sync Point Manager (SPM) should retry the recovery of any outstanding indoubt transactions.
The spm_log_file_sz database manager configuration parameter identifies the SPM log file size in 4K pages.
The spm_max_resync database manager configuration parameter identifies the number of agents that can simultaneously perform resync operations.
The maxappls database configuration parameter specifies the maximum number of active applications allowed.
The value of this parameter must be large enough to accommodate the application (user) connections to the database, as well as the number of indoubt units of work and the number of user transactions that have entered, but not yet completed, a two-phase syncpoint process.
As a result, if you have an environment like the one just described, you may need to increase the value of the maxappls parameter. Increasing the value helps ensure that all processes can be accommodated.
This database configuration parameter specifies whether the RESTART DATABASE routine will be invoked when needed. The default is yes (that is, enabled).
A database containing indoubt transactions will require the RESTART DATABASE command/routine to be invoked in order to start up. If the autorestart option is not enabled, when the last connection to the database is dropped, the next connection will fail and require an explicit RESTART DATABASE again. This condition will exist until the indoubt transaction has been removed either by the transaction manager's resync operation, or through a heuristic operation performed by the administrator. When the RESTART DATABASE is issued, a message will be displayed if there are any indoubt transactions in the database. The administrator can then use the LIST INDOUBT TRANSACTION command and other command line processor commands to find out information about those indoubt transactions.