iilyak commented on a change in pull request #3127: URL: https://github.com/apache/couchdb/pull/3127#discussion_r484871069
########## File path: src/couch_views/src/couch_views_batch.erl ########## @@ -0,0 +1,192 @@ +% 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(couch_views_batch). + + +-export([ + start/0, + success/2, + failure/0 +]). + +-export([ + start/1, + success/3, + failure/1 +]). + + +-callback start(State::term()) -> {NewState::term(), BatchSize::pos_integer()}. +-callback success( + TxSize::non_neg_integer(), + DocsRead::non_neg_integer(), + State::term() + ) -> NewState::term(). +-callback failure(State::term()) -> NewState::term(). + + +-define(DEFAULT_MOD, atom_to_list(?MODULE)). + + +-record(batch_st, { + start_time, + size, + state = search, + search_incr, + sense_incr, + max_tx_size, + max_tx_time, + threshold_penalty +}). + + +start() -> + {Mod, State} = case load_state() of + {M, S} -> + {M, S}; + undefined -> + ModStr = config:get("couch_views", "batch_module", ?DEFAULT_MOD), + ModAtom = list_to_existing_atom(ModStr), + {ModAtom, undefined} + end, + {NewState, BatchSize} = Mod:start(State), + save_state(Mod, NewState), + BatchSize. + + +success(TxSize, DocsRead) -> + {Mod, State} = load_state(), + NewState = Mod:success(TxSize, DocsRead, State), + save_state(Mod, NewState), + ok. + + +failure() -> + {Mod, State} = load_state(), + NewState = Mod:failure(State), + save_state(Mod, NewState), + ok. + + +-spec start(State::term()) -> {NewState::term(), BatchSize::pos_integer()}. +start(undefined) -> + St = #batch_st{ + size = get_config("batch_initial_size", "100"), + search_incr = get_config("batch_search_increment", "500"), + sense_incr = get_config("batch_sense_increment", "100"), + max_tx_size = get_config("batch_max_tx_size", "9000000"), + max_tx_time = get_config("batch_max_tx_time", "4500"), + threshold_penalty = get_config("batch_threshold_penalty", "0.2") + }, + start(validate_opts(St)); + +start(#batch_st{size = Size} = St) -> + NewSt = St#batch_st{ + start_time = erlang:monotonic_time() + }, + {NewSt, Size}. + + +-spec success( + TxSize::non_neg_integer(), + DocsRead::non_neg_integer(), + State::term() + ) -> NewState::term(). +success(TxSize, _DocsRead, #batch_st{} = St) -> + #batch_st{ + start_time = StartTime, + size = Size, + state = State, + search_incr = SearchIncr, + sense_incr = SenseIncr, + max_tx_size = MaxTxSize, + max_tx_time = MaxTxTime, + threshold_penalty = ThresholdPenalty + } = St, + + TxTimeNative = erlang:monotonic_time() - StartTime, + TxTime = erlang:convert_time_unit(TxTimeNative, native, millisecond), + + {NewSize, NewState} = case TxSize > MaxTxSize orelse TxTime > MaxTxTime of + true -> + {round(Size * (1.0 - ThresholdPenalty)), sense}; + false when State == search -> + {Size + SearchIncr, State}; + false when State == sense -> + {Size + SenseIncr, State} + end, + + St#batch_st{ + size = erlang:max(1, NewSize), + state = NewState + }. + + +-spec failure(State::term()) -> NewState::term(). +failure(#batch_st{} = St) -> + St#batch_st{ + size = erlang:max(1, St#batch_st.size div 2), + state = sense + }. + + +validate_opts(St) -> + #batch_st{ + size = Size, + search_incr = SearchIncr, + sense_incr = SenseIncr, + max_tx_size = MaxTxSize, + max_tx_time = MaxTxTime, + threshold_penalty = Penalty + } = St, + St#batch_st{ + size = non_neg_integer(Size, batch_initial_size), + search_incr = non_neg_integer(SearchIncr, batch_search_increment), + sense_incr = non_neg_integer(SenseIncr, batch_sense_increment), + max_tx_size = non_neg_integer(MaxTxSize, batch_max_tx_size), + max_tx_time = non_neg_integer(MaxTxTime, batch_max_tx_time), + threshold_penalty = float_0_to_1(Penalty, batch_threshold_penalty) + }. + + +get_config(Key, Default) -> + config:get("couch_views", Key, Default). + + +non_neg_integer(Str, Name) -> + try + Val = list_to_integer(Str), + true = Val > 0, + Val + catch _:_ -> + erlang:error({invalid_non_neg_integer, {couch_views, Name, Str}}) + end. + + +float_0_to_1(Str, Name) -> + Val = try + list_to_float(Str) + catch error:badarg -> + erlang:error({invalid_float, {couch_views, Name, Str}}) + end, + if Val >= 0.0 andalso Val =< 1.0 -> Val; true -> + erlang:error({float_out_of_range, {couch_views, Name, Str}}) + end. + + +load_state() -> + get(?MODULE). + + +save_state(Mod, Batch) -> Review comment: Should we rename `Batch` into `State`? Because we call it as `save_state(Mod, NewState),` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
