Commit b4353ac6 authored by Jens W. Klein's avatar Jens W. Klein

reduce dup information and compress

parent e1a789c1
...@@ -272,20 +272,13 @@ the value ``None`` rather than a dictionary for :ref:`ghosts ...@@ -272,20 +272,13 @@ the value ``None`` rather than a dictionary for :ref:`ghosts
Volatile Attributes Volatile Attributes
------------------- -------------------
Attributes with names starting with ``_v_`` are treated as volatile. Attributes with names starting with ``_v_`` are volatile,
They are useful for caching data that can be computed from saved data they are never serialized and not saved to the database.
and should not be saved [#cache]_. They are useful for caching data that can be computed from other data[#cache]_.
They are never serialized and not saved to the database.
Volatile attributes are local to a specific active object in memory and Volatile attributes are local to a specific active object in memory and
thus to a specific connection. thus to a specific connection. If an object is removed from the connection
They should be treated as though they can disappear between transactions: cache the volatile attribute is lost.
If an object is removed from the connection cache the volatile attribute is
gone.
Because ZODB connections can be used (in a serial fashion) from one thread
and then another, it is possible to see volatile attributes that were set
in one thread in a process appear in another thread in that process.
Setting a volatile attribute does not cause an object to be considered to Setting a volatile attribute does not cause an object to be considered to
be modified. be modified.
......
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