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B<DB_CREATE>

If any of the files specified do not already exist, create them.

B<DB_INIT_CDB>

Initialise the Concurrent Access Methods

B<DB_INIT_LOCK>

Initialise the Locking sub-system.

B<DB_INIT_LOG>

Initialise the Logging sub-system.

B<DB_INIT_MPOOL>

Initialize the shared memory buffer pool subsystem. This subsystem should be used whenever an application is using any Berkeley DB access method.

B<DB_INIT_TXN>

Initialize the transaction subsystem. This subsystem should be used when recovery and atomicity of multiple operations are important. The DB_INIT_TXN flag implies the DB_INIT_LOG flag.


B<DB_MPOOL_PRIVATE>

Create a private memory pool; see memp_open. Ignored unless DB_INIT_MPOOL is also specified.


B<DB_INIT_MPOOL> is also specified.


B<DB_NOMMAP>

Do not map this database into process memory.


B<DB_RECOVER>

Run normal recovery on this environment before opening it for normal use. If this flag is set, the DB_CREATE flag must also be set since the regions will be removed and recreated.

The db_appinit function returns successfully if DB_RECOVER is specified and no log files exist, so it is necessary to ensure all necessary log files are present before running recovery.


B<DB_PRIVATE>

B<DB_RECOVER_FATAL>

Run catastrophic recovery on this environment before opening it for normal use. If this flag is set, the DB_CREATE flag must also be set since the regions will be removed and recreated.

The db_appinit function returns successfully if DB_RECOVER_FATAL is specified and no log files exist, so it is necessary to ensure all necessary log files are present before running recovery.

B<DB_THREAD>

Ensure that handles returned by the Berkeley DB subsystems are useable by multiple threads within a single process, i.e., that the system is free-threaded.

B<DB_TXN_NOSYNC>

On transaction commit, do not synchronously flush the log; see txn_open. Ignored unless DB_INIT_TXN is also specified.

B<DB_USE_ENVIRON>

The Berkeley DB process' environment may be permitted to specify information to be used when naming files; see Berkeley DB File Naming. As permitting users to specify which files are used can create security problems, environment information will be ...

B<DB_USE_ENVIRON_ROOT>

The Berkeley DB process' environment may be permitted to specify information to be used when naming files; see Berkeley DB File Naming. As permitting users to specify which files are used can create security problems, if the DB_USE_ENVIRON_ROOT flag ...

=item -SetFlags

Calls ENV->set_flags with the supplied bitmask. Use this when you need to make
use of DB_ENV->set_flags before DB_ENV->open is called.

Only valid when Berkeley DB 3.x or better is used.

=item -LockDetect

Specifies what to do when a lock conflict occurs. The value should be one of

B<DB_LOCK_DEFAULT>

Use the default policy as specified by db_deadlock.

B<DB_LOCK_OLDEST>

Abort the oldest transaction.

B<DB_LOCK_RANDOM>

Abort a random transaction involved in the deadlock.

B<DB_LOCK_YOUNGEST>

Abort the youngest transaction.


=item -Verbose

Add extra debugging information to the messages sent to B<-ErrFile>.

=back

=head2 Methods

The environment class has the following methods:

=over 5

=item $env->errPrefix("string") ;

This method is identical to the B<-ErrPrefix> flag. It allows the
error prefix string to be changed dynamically.

=item $env->set_flags(bitmask, 1|0);

=item $txn = $env->TxnMgr()

Constructor for creating a B<TxnMgr> object.
See L<"TRANSACTIONS"> for more details of using transactions.