diff options
| -rw-r--r-- | lib/mnesia/src/mnesia_frag_hash.erl | 18 | ||||
| -rw-r--r-- | lib/mnesia/test/mnesia_frag_hash_test.erl | 94 |
2 files changed, 102 insertions, 10 deletions
diff --git a/lib/mnesia/src/mnesia_frag_hash.erl b/lib/mnesia/src/mnesia_frag_hash.erl index 610ba2535c..d70579c3b3 100644 --- a/lib/mnesia/src/mnesia_frag_hash.erl +++ b/lib/mnesia/src/mnesia_frag_hash.erl @@ -101,21 +101,19 @@ del_frag(OldState) -> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -key_to_frag_number(#hash_state{function = phash, next_n_to_split = SplitN, n_doubles = L}, Key) -> - P = SplitN, - A = erlang:phash(Key, power2(L)), +key_to_frag_number(#hash_state{function = phash, n_fragments = N, n_doubles = L}, Key) -> + A = erlang:phash(Key, power2(L + 1)), if - A < P -> - erlang:phash(Key, power2(L + 1)); + A > N -> + A - power2(L); true -> A end; -key_to_frag_number(#hash_state{function = phash2, next_n_to_split = SplitN, n_doubles = L}, Key) -> - P = SplitN, - A = erlang:phash2(Key, power2(L)) + 1, +key_to_frag_number(#hash_state{function = phash2, n_fragments = N, n_doubles = L}, Key) -> + A = erlang:phash2(Key, power2(L + 1)) + 1, if - A < P -> - erlang:phash2(Key, power2(L + 1)) + 1; + A > N -> + A - power2(L); true -> A end; diff --git a/lib/mnesia/test/mnesia_frag_hash_test.erl b/lib/mnesia/test/mnesia_frag_hash_test.erl new file mode 100644 index 0000000000..095d25e74f --- /dev/null +++ b/lib/mnesia/test/mnesia_frag_hash_test.erl @@ -0,0 +1,94 @@ +-module(mnesia_frag_hash_test). + +-export([test/0]). + +-define(NUM_FRAGS, 20). +-define(NUM_KEYS, 10000). + +-record(hash_state, + {n_fragments, + next_n_to_split, + n_doubles, + function}). + +% OLD mnesia_frag_hash:key_to_frag_number/2. +old_key_to_frag_number(#hash_state{function = phash, next_n_to_split = SplitN, n_doubles = L}, Key) -> + P = SplitN, + A = erlang:phash(Key, power2(L)), + if + A < P -> + erlang:phash(Key, power2(L + 1)); + true -> + A + end; +old_key_to_frag_number(#hash_state{function = phash2, next_n_to_split = SplitN, n_doubles = L}, Key) -> + P = SplitN, + A = erlang:phash2(Key, power2(L)) + 1, + if + A < P -> + erlang:phash2(Key, power2(L + 1)) + 1; + true -> + A + end; +old_key_to_frag_number(OldState, Key) -> + State = convert_old_state(OldState), + old_key_to_frag_number(State, Key). + + +% NEW mnesia_frag_hash:key_to_frag_number/2. +new_key_to_frag_number(#hash_state{function = phash, n_fragments = N, n_doubles = L}, Key) -> + A = erlang:phash(Key, power2(L + 1)), + if + A > N -> + A - power2(L); + true -> + A + end; +new_key_to_frag_number(#hash_state{function = phash2, n_fragments = N, n_doubles = L}, Key) -> + A = erlang:phash2(Key, power2(L + 1)) + 1, + if + A > N -> + A - power2(L); + true -> + A + end; +new_key_to_frag_number(OldState, Key) -> + State = convert_old_state(OldState), + new_key_to_frag_number(State, Key). + + +% Helpers for key_to_frag_number functions. + +power2(Y) -> + 1 bsl Y. % trunc(math:pow(2, Y)). + +convert_old_state({hash_state, N, P, L}) -> + #hash_state{n_fragments = N, + next_n_to_split = P, + n_doubles = L, + function = phash}. + + +test() -> + test2(mnesia_frag_hash:init_state(undefined, undefined)), % phash2 + test2({hash_state, 1, 1, 0}). % phash + +test2(I) -> + test_keys(I), + lists:foldl( + fun(_, S) -> test_frag(S) end, + I, lists:seq(1, ?NUM_FRAGS)), + ok. + +test_frag(State) -> + {State2,_,_} = mnesia_frag_hash:add_frag(State), + test_keys(State2), + State2. + +test_keys(State) -> + [test_key(State, Key) || Key <- lists:seq(1, ?NUM_KEYS)]. + +test_key(State, Key) -> + Old = old_key_to_frag_number(State, Key), + New = new_key_to_frag_number(State, Key), + Old = New. |