�There are 2 causes of the lock time out error. One is when a transaction has to wait too long for another transaciton to release its lock. Locks are released by commit or rollback of a transaction. So, long running transactions can cause other transactions to get lock time outs if they need locks on the same table(s). The other cause of the time out error is dead lock. In this scenario, transaction t1 has a lock on table A and transaction t2 has a lock on table B. If t2 now tries to lock table A and t1 tries to lock table B, they will encounter a lock time out since they are dead locked.
If the lock time out is caused by a long running transaction, the problem can be remedied in one of the following ways:
1) Increase the LockWaitTime property setting. This setting defaults to 10,000 milliseconds. For JDBC connections this property can be set by passing in a Properties Object that has a "lockWaitTime" property setting. For DataStoreConnection JavaBean this property can be set by calling DataStoreConnection.setLockWaitTime().
2) Make the long duration transaction read only if it does not perform any write operations. For JDBC connections this property can be set by calling Connection.setReadOnly(true). For a DataStoreConneciton JavaBean this property can be set by calling DataStoreConnection.setReadOnlyTx(true).
If the lock time out is caused by a deadlock situation, this problem can be resolved in versions of JDataStore 3.51 and above by locking the tables in contention at the start of the transaction. If the tables are locked in the same order, deadlock cannot occur. For JDBC connections The LOCK statement will lock the specified tables in the sorted order of the table names. So in the deadlock scenario discussed above, you can execute the following lock statement to avoid deadlock:
"LOCK A, B"
You can also explicitly lock tables from a DataStoreConnection JavaBean component by calling the DataStoreConnection.lockTableStream() method.
