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| author | Philip Robinson <[email protected]> | 2011-04-27 22:42:18 +1000 |
|---|---|---|
| committer | Philip Robinson <[email protected]> | 2011-04-27 22:42:18 +1000 |
| commit | 67a20c0e2f91e143536202ae969d8211e3ac3da8 (patch) | |
| tree | c2b1e74237ab1c95a41fa11ee5769e03e169ef36 | |
| parent | ef407fad10bccb97aab140f5b99786b8c7b2237a (diff) | |
| download | otp-67a20c0e2f91e143536202ae969d8211e3ac3da8.tar.gz otp-67a20c0e2f91e143536202ae969d8211e3ac3da8.tar.bz2 otp-67a20c0e2f91e143536202ae969d8211e3ac3da8.zip | |
Reduce calls to phash in key_to_frag_number
Original code calls phash 1..2 times, based on which fragment the hashed key
targets and how many fragments exist. New code always calls phash only once.
| -rw-r--r-- | lib/mnesia/src/mnesia_frag_hash.erl | 18 |
1 files changed, 8 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; |