The txn_commit function ends the transaction. In the case of nested
transactions, if the transaction is a parent transaction, committing
the parent transaction causes all unresolved children of the parent to
be committed.
In the case of nested transactions, if the transaction is a child
transaction, its locks are not released, but are acquired by its parent.
While the commit of the child transaction will succeed, the actual
resolution of the child transaction is postponed until the parent
transaction is committed or aborted, i.e., if its parent transaction
commits, it will be committed, and if its parent transaction aborts, it
will be aborted.
The flags parameter must be set to 0 or one of the following
values:
Do not synchronously flush the log. This means the transaction will
exhibit the ACI (atomicity, consistency and isolation) properties, but
not D (durability), i.e., database integrity will be maintained but it is
possible that this transaction may be undone during recovery instead of
being redone.
This behavior may be set for an entire Berkeley DB environment as part of the
DBENV->set_flags interface.
Once the txn_commit function returns, the DB_TXN handle may not
be accessed again. If txn_commit encounters an error, the
transaction and all child transactions of the transaction are aborted.
The txn_commit function returns a non-zero error value on failure and 0 on success.
Errors
The txn_commit function may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions.
If a catastrophic error has occurred, the txn_commit function may fail and return
DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail
in the same way.