diff options
| author | Adam Kocoloski <kocolosk@apache.org> | 2010-03-10 22:12:13 +0000 |
|---|---|---|
| committer | Adam Kocoloski <kocolosk@apache.org> | 2010-03-10 22:12:13 +0000 |
| commit | 68ac2db910581555b9f3063bba2421c8fc2b391b (patch) | |
| tree | 1c8681b1642a6a214023249698e6884ab6817809 /src | |
| parent | b9f749b5529af985abcb53681244416fe8e2b4cc (diff) | |
_stats builtin reduction for min/max/mean/variance
git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@921592 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'src')
| -rw-r--r-- | src/couchdb/couch_query_servers.erl | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/src/couchdb/couch_query_servers.erl b/src/couchdb/couch_query_servers.erl index 3095b199..ff89a67a 100644 --- a/src/couchdb/couch_query_servers.erl +++ b/src/couchdb/couch_query_servers.erl @@ -154,7 +154,10 @@ builtin_reduce(reduce, [<<"_count">>|BuiltinReds], KVs, Acc) -> builtin_reduce(reduce, BuiltinReds, KVs, [Count|Acc]); builtin_reduce(rereduce, [<<"_count">>|BuiltinReds], KVs, Acc) -> Count = builtin_sum_rows(KVs), - builtin_reduce(rereduce, BuiltinReds, KVs, [Count|Acc]). + builtin_reduce(rereduce, BuiltinReds, KVs, [Count|Acc]); +builtin_reduce(Re, [<<"_stats">>|BuiltinReds], KVs, Acc) -> + Stats = builtin_stats(Re, KVs), + builtin_reduce(Re, BuiltinReds, KVs, [Stats|Acc]). builtin_sum_rows(KVs) -> lists:foldl(fun @@ -164,6 +167,24 @@ builtin_sum_rows(KVs) -> throw({invalid_value, <<"builtin _sum function requires map values to be numbers">>}) end, 0, KVs). +builtin_stats(reduce, [[_,First]|Rest]) when is_number(First) -> + Stats = lists:foldl(fun([_K,V], {S,C,Mi,Ma,Sq}) when is_number(V) -> + {S+V, C+1, erlang:min(Mi,V), erlang:max(Ma,V), Sq+(V*V)}; + (_, _) -> + throw({invalid_value, + <<"builtin _stats function requires map values to be numbers">>}) + end, {First,1,First,First,First*First}, Rest), + {Sum, Cnt, Min, Max, Sqr} = Stats, + {[{sum,Sum}, {count,Cnt}, {min,Min}, {max,Max}, {sumsqr,Sqr}]}; + +builtin_stats(rereduce, [[_,First]|Rest]) -> + {[{sum,Sum0}, {count,Cnt0}, {min,Min0}, {max,Max0}, {sumsqr,Sqr0}]} = First, + Stats = lists:foldl(fun([_K,Red], {S,C,Mi,Ma,Sq}) -> + {[{sum,Sum}, {count,Cnt}, {min,Min}, {max,Max}, {sumsqr,Sqr}]} = Red, + {Sum+S, Cnt+C, erlang:min(Min,Mi), erlang:max(Max,Ma), Sqr+Sq} + end, {Sum0,Cnt0,Min0,Max0,Sqr0}, Rest), + {Sum, Cnt, Min, Max, Sqr} = Stats, + {[{sum,Sum}, {count,Cnt}, {min,Min}, {max,Max}, {sumsqr,Sqr}]}. % use the function stored in ddoc.validate_doc_update to test an update. validate_doc_update(DDoc, EditDoc, DiskDoc, Ctx, SecObj) -> |