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Diffstat (limited to 'src/couchdb/couch_rep_reader.erl')
| -rw-r--r-- | src/couchdb/couch_rep_reader.erl | 277 |
1 files changed, 0 insertions, 277 deletions
diff --git a/src/couchdb/couch_rep_reader.erl b/src/couchdb/couch_rep_reader.erl deleted file mode 100644 index 1e8ca074..00000000 --- a/src/couchdb/couch_rep_reader.erl +++ /dev/null @@ -1,277 +0,0 @@ -% 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_rep_reader). --behaviour(gen_server). --export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, - code_change/3]). - --export([start_link/4, next/1]). - --import(couch_util, [encode_doc_id/1]). - --define (BUFFER_SIZE, 1000). --define (MAX_CONCURRENT_REQUESTS, 100). - --include("couch_db.hrl"). - --record (state, { - parent, - source, - missing_revs, - reader_loop, - reader_from = [], - count = 0, - docs = queue:new(), - reply_to = nil, - complete = false, - monitor_count = 0, - pending_doc_request = nil, - requested_seqs = [], - opened_seqs = [] -}). - -start_link(Parent, Source, MissingRevs, PostProps) -> - gen_server:start_link(?MODULE, [Parent, Source, MissingRevs, PostProps], []). - -next(Pid) -> - gen_server:call(Pid, next_docs, infinity). - -init([Parent, Source, MissingRevs, _PostProps]) -> - process_flag(trap_exit, true), - Self = self(), - ReaderLoop = spawn_link( - fun() -> reader_loop(Self, Parent, Source, MissingRevs) end), - State = #state{ - parent = Parent, - source = Source, - missing_revs = MissingRevs, - reader_loop = ReaderLoop - }, - {ok, State}. - -handle_call({add_docs, Seq, Docs}, From, State) -> - State#state.parent ! {update_stats, docs_read, length(Docs)}, - handle_add_docs(Seq, lists:flatten(Docs), From, State); - -handle_call({add_request_seqs, Seqs}, _From, State) -> - SeqList = State#state.requested_seqs, - {reply, ok, State#state{requested_seqs = lists:merge(Seqs, SeqList)}}; - -handle_call(next_docs, From, State) -> - handle_next_docs(From, State); - -handle_call({open_remote_doc, Id, Seq, Revs}, From, State) -> - handle_open_remote_doc(Id, Seq, Revs, From, State). - -handle_cast(_Msg, State) -> - {noreply, State}. - -handle_info({'DOWN', _, _, _, Reason}, State) -> - handle_monitor_down(Reason, State); - -handle_info({'EXIT', Loop, complete}, #state{reader_loop=Loop} = State) -> - handle_reader_loop_complete(State). - -terminate(_Reason, _State) -> - % ?LOG_INFO("rep reader terminating with reason ~p", [_Reason]), - ok. - -code_change(_OldVsn, State, _Extra) -> - {ok, State}. - -%internal funs - -handle_add_docs(_Seq, [], _From, State) -> - {reply, ok, State}; -handle_add_docs(Seq, DocsToAdd, From, #state{reply_to=nil} = State) -> - State1 = update_sequence_lists(Seq, State), - NewState = State1#state{ - docs = queue:join(State1#state.docs, queue:from_list(DocsToAdd)), - count = State1#state.count + length(DocsToAdd) - }, - if NewState#state.count < ?BUFFER_SIZE -> - {reply, ok, NewState}; - true -> - {noreply, NewState#state{reader_from=[From|State#state.reader_from]}} - end; -handle_add_docs(Seq, DocsToAdd, _From, #state{count=0} = State) -> - NewState = update_sequence_lists(Seq, State), - HighSeq = calculate_new_high_seq(NewState), - gen_server:reply(State#state.reply_to, {HighSeq, DocsToAdd}), - {reply, ok, NewState#state{reply_to=nil}}. - -handle_next_docs(From, #state{count=0} = State) -> - if State#state.complete -> - {stop, normal, {complete, calculate_new_high_seq(State)}, State}; - true -> - {noreply, State#state{reply_to=From}} - end; -handle_next_docs(_From, State) -> - #state{ - reader_from = ReaderFrom, - docs = Docs - } = State, - [gen_server:reply(F, ok) || F <- ReaderFrom], - NewState = State#state{count=0, reader_from=[], docs=queue:new()}, - {reply, {calculate_new_high_seq(State), queue:to_list(Docs)}, NewState}. - -handle_open_remote_doc(Id, Seq, Revs, From, #state{monitor_count=N} = State) - when N > ?MAX_CONCURRENT_REQUESTS -> - {noreply, State#state{pending_doc_request={From,Id,Seq,Revs}}}; -handle_open_remote_doc(Id, Seq, Revs, _, #state{source=#http_db{}} = State) -> - #state{ - monitor_count = Count, - source = Source - } = State, - {_, _Ref} = spawn_document_request(Source, Id, Seq, Revs), - {reply, ok, State#state{monitor_count = Count+1}}. - -handle_monitor_down(normal, #state{pending_doc_request=nil, reply_to=nil, - monitor_count=1, complete=waiting_on_monitors} = State) -> - {noreply, State#state{complete=true, monitor_count=0}}; -handle_monitor_down(normal, #state{pending_doc_request=nil, reply_to=From, - monitor_count=1, complete=waiting_on_monitors} = State) -> - gen_server:reply(From, {complete, calculate_new_high_seq(State)}), - {stop, normal, State#state{complete=true, monitor_count=0}}; -handle_monitor_down(normal, #state{pending_doc_request=nil} = State) -> - #state{monitor_count = Count} = State, - {noreply, State#state{monitor_count = Count-1}}; -handle_monitor_down(normal, State) -> - #state{ - source = Source, - pending_doc_request = {From, Id, Seq, Revs} - } = State, - gen_server:reply(From, ok), - {_, _NewRef} = spawn_document_request(Source, Id, Seq, Revs), - {noreply, State#state{pending_doc_request=nil}}; -handle_monitor_down(Reason, State) -> - {stop, Reason, State}. - -handle_reader_loop_complete(#state{reply_to=nil, monitor_count=0} = State) -> - {noreply, State#state{complete = true}}; -handle_reader_loop_complete(#state{monitor_count=0} = State) -> - HighSeq = calculate_new_high_seq(State), - gen_server:reply(State#state.reply_to, {complete, HighSeq}), - {stop, normal, State}; -handle_reader_loop_complete(State) -> - {noreply, State#state{complete = waiting_on_monitors}}. - -calculate_new_high_seq(#state{requested_seqs=[], opened_seqs=[Open|_]}) -> - Open; -calculate_new_high_seq(#state{requested_seqs=[Req|_], opened_seqs=[Open|_]}) - when Req < Open -> - 0; -calculate_new_high_seq(#state{opened_seqs=[]}) -> - 0; -calculate_new_high_seq(State) -> - hd(State#state.opened_seqs). - -split_revlist(Rev, {[CurrentAcc|Rest], BaseLength, Length}) -> - case Length+size(Rev)+3 > 8192 of - false -> - {[[Rev|CurrentAcc] | Rest], BaseLength, Length+size(Rev)+3}; - true -> - {[[Rev],CurrentAcc|Rest], BaseLength, BaseLength} - end. - -% We store outstanding requested sequences and a subset of already opened -% sequences in 2 ordered lists. The subset of opened seqs is a) the largest -% opened seq smaller than the smallest outstanding request seq plus b) all the -% opened seqs greater than the smallest outstanding request. I believe its the -% minimal set of info needed to correctly calculate which seqs have been -% replicated (because remote docs can be opened out-of-order) -- APK -update_sequence_lists(Seq, State) -> - Requested = lists:delete(Seq, State#state.requested_seqs), - AllOpened = lists:merge([Seq], State#state.opened_seqs), - Opened = case Requested of - [] -> - [lists:last(AllOpened)]; - [EarliestReq|_] -> - case lists:splitwith(fun(X) -> X < EarliestReq end, AllOpened) of - {[], Greater} -> - Greater; - {Less, Greater} -> - [lists:last(Less) | Greater] - end - end, - State#state{ - requested_seqs = Requested, - opened_seqs = Opened - }. - -open_doc_revs(#http_db{url = Url} = DbS, DocId, Revs) -> - %% all this logic just splits up revision lists that are too long for - %% MochiWeb into multiple requests - BaseQS = [{revs,true}, {latest,true}, {att_encoding_info,true}], - BaseReq = DbS#http_db{resource=encode_doc_id(DocId), qs=BaseQS}, - BaseLength = length(couch_rep_httpc:full_url(BaseReq) ++ "&open_revs=[]"), - - {RevLists, _, _} = lists:foldl(fun split_revlist/2, - {[[]], BaseLength, BaseLength}, couch_doc:revs_to_strs(Revs)), - - Requests = [BaseReq#http_db{ - qs = [{open_revs, ?JSON_ENCODE(RevList)} | BaseQS] - } || RevList <- RevLists], - JsonResults = lists:flatten([couch_rep_httpc:request(R) || R <- Requests]), - - Transform = - fun({[{<<"ok">>, Json}]}, Acc) -> - #doc{id=Id, revs=Rev, atts=Atts} = Doc = couch_doc:from_json_obj(Json), - Doc1 = Doc#doc{ - atts=[couch_rep_att:convert_stub(A, {DbS,Id,Rev}) || A <- Atts] - }, - [Doc1 | Acc]; - ({ErrorProps}, Acc) -> - Err = couch_util:get_value(<<"error">>, ErrorProps, - ?JSON_ENCODE({ErrorProps})), - ?LOG_ERROR("Replicator: error accessing doc ~s at ~s, reason: ~s", - [DocId, couch_util:url_strip_password(Url), Err]), - Acc - end, - lists:reverse(lists:foldl(Transform, [], JsonResults)). - -reader_loop(ReaderServer, Parent, Source, MissingRevsServer) -> - case couch_rep_missing_revs:next(MissingRevsServer) of - complete -> - exit(complete); - {_HighSeq, IdsRevs} -> - % to be safe, make sure Results are sorted by source_seq - SortedIdsRevs = lists:keysort(2, IdsRevs), - RequestSeqs = [S || {_,S,_} <- SortedIdsRevs], - gen_server:call(ReaderServer, {add_request_seqs, RequestSeqs}, infinity), - case Source of - #http_db{} -> - [gen_server:call(ReaderServer, {open_remote_doc, Id, Seq, Revs}, - infinity) || {Id,Seq,Revs} <- SortedIdsRevs], - reader_loop(ReaderServer, Parent, Source, MissingRevsServer); - _Local -> - {ok, Source2} = couch_db:open( - Source#db.name, [{user_ctx, Source#db.user_ctx}]), - lists:foreach(fun({Id,Seq,Revs}) -> - {ok, Docs} = couch_db:open_doc_revs(Source2, Id, Revs, [latest]), - JustTheDocs = [Doc || {ok, Doc} <- Docs], - gen_server:call(ReaderServer, {add_docs, Seq, JustTheDocs}, - infinity) - end, SortedIdsRevs), - couch_db:close(Source2), - reader_loop(ReaderServer, Parent, Source2, MissingRevsServer) - end - end. - -spawn_document_request(Source, Id, Seq, Revs) -> - Server = self(), - SpawnFun = fun() -> - Results = open_doc_revs(Source, Id, Revs), - gen_server:call(Server, {add_docs, Seq, Results}, infinity) - end, - spawn_monitor(SpawnFun). |