[erlang-bugs] documentation bug(s) - mnesia:lock/2

Ulf Wiger <>
Mon Oct 8 14:59:56 CEST 2007

In the documentation for mnesia:lock/2,


one can read the following:

Currently, two kinds of LockItem's are supported by this function:

"{table, Tab}
    This acquires a lock of type LockKind on the entire table Tab.
{global, GlobalKey, Nodes}
    This acquires a lock of type LockKind on the global resource
GlobalKey. The lock is acquired on all active nodes in the Nodes list.

but the function also supports a third kind of LockItem (perhaps the most

{record, Tab, Key}

Furthermore, it states that stick_write is not supported by the
function, but looking at the source, not only is sticky_write
(note the spelling) supported, but also 'none'.

Finally, looking at the function prototype:

lock(LockItem, LockKind) -> GoodNodes | transaction abort

This doesn't seem to be correct either. The function returns
the result of mnesia:read({Tab,Key}), or something to that

Ulf W

Ulf W

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