diff options
author | Dan Gudmundsson <[email protected]> | 2019-01-25 13:05:18 +0100 |
---|---|---|
committer | GitHub <[email protected]> | 2019-01-25 13:05:18 +0100 |
commit | 5ed2f3d9757c9f2b8e49a4796e2a384c938d80dd (patch) | |
tree | 980ffc10ff8629430acc0fd514232457939a65cd | |
parent | 7cd0271e226ddd727867b0f923a00d9f58167a5f (diff) | |
parent | 8332bff4ceebd08d103623f59f7761d8e9367f69 (diff) | |
download | otp-5ed2f3d9757c9f2b8e49a4796e2a384c938d80dd.tar.gz otp-5ed2f3d9757c9f2b8e49a4796e2a384c938d80dd.tar.bz2 otp-5ed2f3d9757c9f2b8e49a4796e2a384c938d80dd.zip |
Merge pull request #2029 from richcarl/mnesia-read-local-if-available
Mnesia should always use the local context if available
OTP-15550
-rw-r--r-- | lib/mnesia/src/mnesia.erl | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/lib/mnesia/src/mnesia.erl b/lib/mnesia/src/mnesia.erl index 223dba3f90..77afb8250c 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, LockKind); _Protocol -> dirty_read(Tab, Key) end; @@ -1202,14 +1204,20 @@ 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, _LockKind) -> + ObjsFun(); % standard normal fast case +add_written(Written, Tab, ObjsFun, LockKind) -> case val({Tab, setorbag}) of bag -> - add_written_to_bag(Written, Objs, []); + add_written_to_bag(Written, ObjsFun(), []); + _ when LockKind == read; + LockKind == write -> + add_written_to_set(Written); _ -> + _ = ObjsFun(), % Fall back to request new lock and read from source add_written_to_set(Written) end. |