DbEnv::set_data_dir(const char *dir);
Set the path of a directory to be used as the location of the access
method database files. Paths specified to the Db::open function
will be searched relative to this path. Paths set using this interface
are additive, and specifying more than one will result in each specified
directory being searched for database files. If any directories are
specified, created database files will always be created in the first path
If no database directories are specified, database files can exist only
in the environment home directory. See Berkeley DB File Naming for more information.
For the greatest degree of recoverability from system or application
failure, database files and log files should be located on separate
The DbEnv::set_data_dir method configures operations performed using the specified
DbEnv handle, not all operations performed on the underlying
The DbEnv::set_data_dir interface may not be called after the DbEnv::open
interface is called.
If the database environment already exists when
DbEnv::open is called, the information specified to DbEnv::set_data_dir
must be consistent with the existing environment or corruption can
The DbEnv::set_data_dir method either returns a non-zero error value or throws an exception that
encapsulates a non-zero error value on failure, and returns 0 on success.
The database environment's data directory may also be set using the environment's
DB_CONFIG file. The syntax of the entry in that file is a
single line with the string "set_data_dir", one or more whitespace characters,
and the directory name. Because the DB_CONFIG file is read when the database
environment is opened, it will silently overrule configuration done
before that time.
The DbEnv::set_data_dir method may fail and throw an exception or return a non-zero error for the following conditions:
- An invalid flag value or parameter was specified.
Called after DbEnv::open was called.
The DbEnv::set_data_dir method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods.
If a catastrophic error has occurred, the DbEnv::set_data_dir method may fail and
either return DB_RUNRECOVERY or throw a
in which case all subsequent Berkeley DB calls will fail in the same way.
Database Environments and Related Methods
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