Caching

When you request a database the first time, audb will unpack (and convert) annotations and data to <cache>/<name>/<version>/<flavor>/. Next time your request it again, audb will directly load the database from there.

audb distinguishes two <cache> folders. A system wide shared cache folder and a user cache folder.

Shared cache

By default the shared cache is located at

>>> audb.default_cache_root(shared=True)
'/data/audb'

and is meant to be shared by several users.

In order to provide read and write access to all users to the shared cache folder, they need to be in the same group and you have to adjust the rights of the shared cache folder with

$ chmod 775 /data/audb  # set right of cache folder
$ chmod g+s /data/audb  # content inherits group ownership
$ setfacl -d -m u::rwx,g::rwx,o::rx- /data/audb  # content inherits rights

User cache

The second cache folder should be accessible to you only. By default it points to

>>> audb.default_cache_root(shared=False)
'.../audb'

When you request a database with audb.load(), audb first looks for it in the shared cache folder and afterwards in your local cache folder.

Changing cache locations

There are four ways to change the default locations:

1. By setting the argument cache_root during a function call, e.g.

>>> db = audb.load("emodb", ..., cache_root="/cache/root/audb")

2. System-wide by setting the following system variables

export AUDB_CACHE_ROOT=/new/local/cache/audb
export AUDB_SHARED_CACHE_ROOT=/new/shared/cache/audb

3. Program-wide by overwriting the default values in audb.config

>>> audb.config.SHARED_CACHE_ROOT = "/new/shared/cache/audb"
>>> audb.default_cache_root(shared=True)
'/new/shared/cache/audb'

>>> audb.config.CACHE_ROOT = "/new/local/cache/audb"
>>> audb.default_cache_root(shared=False)
'/new/local/cache/audb'

4. System wide by using the configuration file ~/.config/audb.yaml

Note, 1. overwrites all other methods, 2. overwrites 3. and 4., and so on.