- data manager
The object responsible for storing and loading an object's
pickled data
in a backing store. Also called ajar
.- jar
Alias for
data manager
: short for "pickle jar", because it traditionally holds thepickled data
of persistent objects.- object cache
An MRU cache for objects associated with a given
data manager
.- ghost
An object whose
pickled data
has not yet been loaded from itsjar
. Accessing or mutating any of its attributes causes that data to be loaded, which is referred to asactivation
.- volatile attribute
Attributes of a persistent object which are not captured as part of its
pickled data
. These attributes thus disappear duringdeactivation
orinvalidation
.- pickled data
The serialized data of a persistent object, stored in and retrieved from a backing store by a
data manager
.- activation
Moving an object from the
GHOST
state to theUPTODATE
state, load itspickled data
from itsjar
.- deactivation
Moving an object from the
UPTODATE
state to theGHOST
state, discarding itspickled data
.- invalidation
Moving an object from either the
UPTODATE
state or theCHANGED
state to theGHOST
state, discarding itspickled data
.- object id
The stable identifier that uniquely names a particular object. This is analogous to Python's id, but unlike id, object ids remain the same for a given object across different processes.