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Diffstat (limited to 'deps/fabric/src/fabric_view_map.erl')
| -rw-r--r-- | deps/fabric/src/fabric_view_map.erl | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/deps/fabric/src/fabric_view_map.erl b/deps/fabric/src/fabric_view_map.erl new file mode 100644 index 00000000..96741a8e --- /dev/null +++ b/deps/fabric/src/fabric_view_map.erl @@ -0,0 +1,151 @@ +% Copyright 2010 Cloudant +% +% Licensed under the Apache License, Version 2.0 (the "License"); you may not +% use this file except in compliance with the License. You may obtain a copy of +% the License at +% +% http://www.apache.org/licenses/LICENSE-2.0 +% +% Unless required by applicable law or agreed to in writing, software +% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +% License for the specific language governing permissions and limitations under +% the License. + +-module(fabric_view_map). + +-export([go/6]). + +-include("fabric.hrl"). +-include_lib("mem3/include/mem3.hrl"). +-include_lib("couch/include/couch_db.hrl"). + +go(DbName, GroupId, View, Args, Callback, Acc0) when is_binary(GroupId) -> + {ok, DDoc} = fabric:open_doc(DbName, <<"_design/", GroupId/binary>>, []), + go(DbName, DDoc, View, Args, Callback, Acc0); + +go(DbName, DDoc, View, Args, Callback, Acc0) -> + Shards = fabric_view:get_shards(DbName, Args), + Workers = fabric_util:submit_jobs(Shards, map_view, [DDoc, View, Args]), + BufferSize = couch_config:get("fabric", "map_buffer_size", "2"), + #view_query_args{limit = Limit, skip = Skip, keys = Keys} = Args, + State = #collector{ + db_name=DbName, + query_args = Args, + callback = Callback, + buffer_size = list_to_integer(BufferSize), + counters = fabric_dict:init(Workers, 0), + skip = Skip, + limit = Limit, + keys = fabric_view:keydict(Keys), + sorted = Args#view_query_args.sorted, + user_acc = Acc0 + }, + RexiMon = fabric_util:create_monitors(Workers), + try rexi_utils:recv(Workers, #shard.ref, fun handle_message/3, + State, infinity, 1000 * 60 * 60) of + {ok, NewState} -> + {ok, NewState#collector.user_acc}; + {timeout, NewState} -> + Callback({error, timeout}, NewState#collector.user_acc); + {error, Resp} -> + {ok, Resp} + after + rexi_monitor:stop(RexiMon), + fabric_util:cleanup(Workers) + end. + +handle_message({rexi_DOWN, _, {_, NodeRef}, _}, _, State) -> + fabric_view:remove_down_shards(State, NodeRef); + +handle_message({rexi_EXIT, Reason}, Worker, State) -> + #collector{callback=Callback, counters=Counters0, user_acc=Acc} = State, + Counters = fabric_dict:erase(Worker, Counters0), + case fabric_view:is_progress_possible(Counters) of + true -> + {ok, State#collector{counters = Counters}}; + false -> + {ok, Resp} = Callback({error, fabric_util:error_info(Reason)}, Acc), + {error, Resp} + end; + +handle_message({total_and_offset, Tot, Off}, {Worker, From}, State) -> + #collector{ + callback = Callback, + counters = Counters0, + total_rows = Total0, + offset = Offset0, + user_acc = AccIn + } = State, + case fabric_dict:lookup_element(Worker, Counters0) of + undefined -> + % this worker lost the race with other partition copies, terminate + gen_server:reply(From, stop), + {ok, State}; + 0 -> + gen_server:reply(From, ok), + Counters1 = fabric_dict:update_counter(Worker, 1, Counters0), + Counters2 = fabric_view:remove_overlapping_shards(Worker, Counters1), + Total = Total0 + Tot, + Offset = Offset0 + Off, + case fabric_dict:any(0, Counters2) of + true -> + {ok, State#collector{ + counters = Counters2, + total_rows = Total, + offset = Offset + }}; + false -> + FinalOffset = erlang:min(Total, Offset+State#collector.skip), + {Go, Acc} = Callback({total_and_offset, Total, FinalOffset}, AccIn), + {Go, State#collector{ + counters = fabric_dict:decrement_all(Counters2), + total_rows = Total, + offset = FinalOffset, + user_acc = Acc + }} + end + end; + +handle_message(#view_row{}, {_, _}, #collector{limit=0} = State) -> + #collector{callback=Callback} = State, + {_, Acc} = Callback(complete, State#collector.user_acc), + {stop, State#collector{user_acc=Acc}}; + +handle_message(#view_row{} = Row, {_,From}, #collector{sorted=false} = St) -> + #collector{callback=Callback, user_acc=AccIn, limit=Limit} = St, + {Go, Acc} = Callback(fabric_view:transform_row(Row), AccIn), + gen_server:reply(From, ok), + {Go, St#collector{user_acc=Acc, limit=Limit-1}}; + +handle_message(#view_row{} = Row, {Worker, From}, State) -> + #collector{ + query_args = #view_query_args{direction=Dir}, + counters = Counters0, + rows = Rows0, + keys = KeyDict + } = State, + Rows = merge_row(Dir, KeyDict, Row#view_row{worker=Worker}, Rows0), + Counters1 = fabric_dict:update_counter(Worker, 1, Counters0), + State1 = State#collector{rows=Rows, counters=Counters1}, + State2 = fabric_view:maybe_pause_worker(Worker, From, State1), + fabric_view:maybe_send_row(State2); + +handle_message(complete, Worker, State) -> + Counters = fabric_dict:update_counter(Worker, 1, State#collector.counters), + fabric_view:maybe_send_row(State#collector{counters = Counters}). + +merge_row(fwd, undefined, Row, Rows) -> + lists:merge(fun(#view_row{key=KeyA, id=IdA}, #view_row{key=KeyB, id=IdB}) -> + couch_view:less_json([KeyA, IdA], [KeyB, IdB]) + end, [Row], Rows); +merge_row(rev, undefined, Row, Rows) -> + lists:merge(fun(#view_row{key=KeyA, id=IdA}, #view_row{key=KeyB, id=IdB}) -> + couch_view:less_json([KeyB, IdB], [KeyA, IdA]) + end, [Row], Rows); +merge_row(_, KeyDict, Row, Rows) -> + lists:merge(fun(#view_row{key=A, id=IdA}, #view_row{key=B, id=IdB}) -> + if A =:= B -> IdA < IdB; true -> + dict:fetch(A, KeyDict) < dict:fetch(B, KeyDict) + end + end, [Row], Rows). |