LmdbBackend

class mmengine.fileio.LmdbBackend(db_path, readonly=True, lock=False, readahead=False, **kwargs)

Lmdb storage backend.

Parameters:

• db_path (str) – Lmdb database path.

• readonly (bool) – Lmdb environment parameter. If True, disallow any write operations. Defaults to True.

• lock (bool) – Lmdb environment parameter. If False, when concurrent access occurs, do not lock the database. Defaults to False.

• readahead (bool) – Lmdb environment parameter. If False, disable the OS filesystem readahead mechanism, which may improve random read performance when a database is larger than RAM. Defaults to False.

• **kwargs – Keyword arguments passed to lmdb.open.

db_path

Lmdb database path.

Type:

str

get(filepath)

Get values according to the filepath.

Parameters:

filepath (str or Path) – Here, filepath is the lmdb key.

Returns:

Expected bytes object.

Return type:

bytes

Examples

>>> backend = LmdbBackend('path/to/lmdb')
>>> backend.get('key')
b'hello world'