上一篇博文介绍了mnesia的事务提交准备过程，为每个事务参与结点构造了其提交结构commit，下面将进入到提交过程中，此后将继续分析。

?

mnesia_tm.erl

?

multi_commit(sym_trans, _Maj = [], Tid, CR, Store) ->

? ? {DiscNs, RamNs} = commit_nodes(CR, [], []),

? ? Pending = mnesia_checkpoint:tm_enter_pending(Tid, DiscNs, RamNs),

? ? ?ets_insert(Store, Pending),

?

? ? {WaitFor, Local} = ask_commit(sym_trans, Tid, CR, DiscNs, RamNs),

? ? {Outcome, []} = rec_all(WaitFor, Tid, do_commit, []),

? ? ?eval_debug_fun({?MODULE, multi_commit_sym},

? ?[{tid, Tid}, {outcome, Outcome}]),

? ? rpc:abcast(DiscNs -- [node()], ?MODULE, {Tid, Outcome}),

? ? rpc:abcast(RamNs -- [node()], ?MODULE, {Tid, Outcome}),

? ? case Outcome of

do_commit ->

? ?mnesia_recover:note_decision(Tid, committed),

? ?do_dirty(Tid, Local),

? ?mnesia_locker:release_tid(Tid),

? ??MODULE ! {delete_transaction, Tid};

{do_abort, _Reason} ->

? ?mnesia_recover:note_decision(Tid, aborted)

? ? end,

? ? ?eval_debug_fun({?MODULE, multi_commit_sym, post},

? ?[{tid, Tid}, {outcome, Outcome}]),

Outcome;

commit_nodes([C | Tail], AccD, AccR)

? ? ? ? when C#commit.disc_copies == [],

? ? ? ? ? ? ?C#commit.disc_only_copies ?== [],

? ? ? ? ? ? ?C#commit.schema_ops == [] ->

? ? commit_nodes(Tail, AccD, [C#commit.node | AccR]);

commit_nodes([C | Tail], AccD, AccR) ->

? ? commit_nodes(Tail, [C#commit.node | AccD], AccR);

commit_nodes([], AccD, AccR) ->

? ? {AccD, AccR}.

取出所有参与事务的结点，这实质上等同于where_to_commit属性记录的所有结点。