The database parameters of SAP MaxDB influence the SAP MaxDB SQL lock management.

a) MaxUserTasks (MAXUSERTASKS):

The database parameter MaxUserTasks defines the maximum number of parallel user sessions.

b) MaxSQLLocks (MAXLOCKS):

The database parameter MaxSQLLocks defines the maximum number of line locks and table locks that can be held or requested at the same time. If the MaxSQLLocks VALUE is reached, statements that request locks are REJECTED (-1000: Too many lock requests).

c) RequestTimeout (REQUEST_TIMEOUT):

The database parameter RequestTimeout defines how long a transaction must wait for the assignment of a lock. If this wait time has expired before the lock is assigned, the transaction TERMINATES with an error.

d) DeadlockDetectionLevel (DEADLOCK_DETECTION):

The database parameter DeadlockDetectionLevel defines the maximum depth of search for the deadlock detection with SQL locks.

If this database parameter is set to value 0, the deadlock detection is deactivated (in other words, deadlocks are removed only by RequestTimeout). A value that is higher than 0 defines the depth of search. Up to the specified depth of search, deadlocks are detected and immediately removed. The initial value for the deadlock detection is 4. A higher value RESULTS in considerable costs. Consider using a higher value only if an application triggers SERIOUS deadlock problems that cannot be solved in the application.

The database parameters of SAP MaxDB influence the SAP MaxDB SQL lock management.

a) MaxUserTasks (MAXUSERTASKS):

The database parameter MaxUserTasks defines the maximum number of parallel user sessions.

b) MaxSQLLocks (MAXLOCKS):

The database parameter MaxSQLLocks defines the maximum number of line locks and table locks that can be held or requested at the same time. If the MaxSQLLocks value is reached, statements that request locks are rejected (-1000: Too many lock requests).

c) RequestTimeout (REQUEST_TIMEOUT):

The database parameter RequestTimeout defines how long a transaction must wait for the assignment of a lock. If this wait time has expired before the lock is assigned, the transaction terminates with an error.

d) DeadlockDetectionLevel (DEADLOCK_DETECTION):

The database parameter DeadlockDetectionLevel defines the maximum depth of search for the deadlock detection with SQL locks.

If this database parameter is set to value 0, the deadlock detection is deactivated (in other words, deadlocks are removed only by RequestTimeout). A value that is higher than 0 defines the depth of search. Up to the specified depth of search, deadlocks are detected and immediately removed. The initial value for the deadlock detection is 4. A higher value results in considerable costs. Consider using a higher value only if an application triggers serious deadlock problems that cannot be solved in the application.