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author | Magnus Fröberg <[email protected]> | 2018-11-19 15:28:37 +0100 |
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committer | Richard Carlsson <[email protected]> | 2018-11-22 13:28:31 +0100 |
commit | 482cde369a02391b30511e10fb24a1a836d643e8 (patch) | |
tree | e99e4ebf184ee504599b00c5f366ae157d5a9881 /lib/mnesia/src/mnesia.erl | |
parent | a411b7dedd42cc4cbe160eec3e5aae8027e7833b (diff) | |
download | otp-482cde369a02391b30511e10fb24a1a836d643e8.tar.gz otp-482cde369a02391b30511e10fb24a1a836d643e8.tar.bz2 otp-482cde369a02391b30511e10fb24a1a836d643e8.zip |
Mnesia should always use the local context if available
Do not read from (set | order_set) source table if the content is
already in the transactional context (i.e., a previous write/delete).
Diffstat (limited to 'lib/mnesia/src/mnesia.erl')
-rw-r--r-- | lib/mnesia/src/mnesia.erl | 36 |
1 files changed, 20 insertions, 16 deletions
diff --git a/lib/mnesia/src/mnesia.erl b/lib/mnesia/src/mnesia.erl index 223dba3f90..89b7207483 100644 --- a/lib/mnesia/src/mnesia.erl +++ b/lib/mnesia/src/mnesia.erl @@ -838,18 +838,20 @@ read(Tid, Ts, Tab, Key, LockKind) tid -> Store = Ts#tidstore.store, Oid = {Tab, Key}, - Objs = - case LockKind of - read -> - mnesia_locker:rlock(Tid, Store, Oid); - write -> - mnesia_locker:rwlock(Tid, Store, Oid); - sticky_write -> - mnesia_locker:sticky_rwlock(Tid, Store, Oid); - _ -> - abort({bad_type, Tab, LockKind}) - end, - add_written(?ets_lookup(Store, Oid), Tab, Objs); + ObjsFun = + fun() -> + case LockKind of + read -> + mnesia_locker:rlock(Tid, Store, Oid); + write -> + mnesia_locker:rwlock(Tid, Store, Oid); + sticky_write -> + mnesia_locker:sticky_rwlock(Tid, Store, Oid); + _ -> + abort({bad_type, Tab, LockKind}) + end + end, + add_written(?ets_lookup(Store, Oid), Tab, ObjsFun); _Protocol -> dirty_read(Tab, Key) end; @@ -1202,13 +1204,15 @@ add_previous(_Tid, Ts, _Type, Tab) -> %% This routine fixes up the return value from read/1 so that %% it is correct with respect to what this particular transaction %% has already written, deleted .... etc +%% The actual read from the table is not done if not needed due to local +%% transaction context, and if so, no extra read lock is needed either. -add_written([], _Tab, Objs) -> - Objs; % standard normal fast case -add_written(Written, Tab, Objs) -> +add_written([], _Tab, ObjsFun) -> + ObjsFun(); % standard normal fast case +add_written(Written, Tab, ObjsFun) -> case val({Tab, setorbag}) of bag -> - add_written_to_bag(Written, Objs, []); + add_written_to_bag(Written, ObjsFun(), []); _ -> add_written_to_set(Written) end. |