nickva commented on a change in pull request #1972: Introduce Shard Splitting To CouchDB URL: https://github.com/apache/couchdb/pull/1972#discussion_r268386865
########## File path: src/mem3/src/mem3_reshard_index.erl ########## @@ -0,0 +1,169 @@ +% 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(mem3_reshard_index). + + +-export([ + design_docs/1, + target_indices/2, + spawn_builders/1 +]). + + +-include_lib("mem3/include/mem3.hrl"). +-include_lib("couch/include/couch_db.hrl"). + + +%% Public API + +design_docs(DbName) -> + try + case fabric_design_docs(mem3:dbname(DbName)) of + {error, {maintenance_mode, _, _Node}} -> + {ok, []}; + {ok, DDocs} -> + JsonDocs = [couch_doc:from_json_obj(DDoc) || DDoc <- DDocs], + {ok, JsonDocs}; + Else -> + Else + end + catch error:database_does_not_exist -> + {ok, []} + end. + + +target_indices(Docs, Targets) -> + Indices = [[indices(N, D) || D <- Docs] || #shard{name = N} <- Targets], + lists:flatten(Indices). + + +spawn_builders(Indices) -> + Results = [build_index(Index) || Index <- Indices], + Oks = [{ok, Pid} || {ok, Pid} <- Results, is_pid(Pid)], + case Results -- Oks of + [] -> + {ok, [Pid || {ok, Pid} <- Results]}; + Error -> + % Do a all or nothing pattern, if some indices could not be + % spawned, kill the spawned ones and and return the error. + ErrMsg = "~p failed to spawn index builders: ~p ~p", + couch_log:error(ErrMsg, [?MODULE, Error, Indices]), + lists:foreach(fun({ok, Pid}) -> + catch unlink(Pid), + catch exit(Pid, kill) + end, Oks), + {error, Error} + end. + + +%% Private API + +fabric_design_docs(DbName) -> + case couch_util:with_proc(fabric, design_docs, [DbName], infinity) of + {ok, Resp} -> Resp; + {error, Error} -> Error + end. + + +indices(DbName, Doc) -> + mrview_indices(DbName, Doc) ++ + [dreyfus_indices(DbName, Doc) || has_app(dreyfus)] ++ Review comment: Emilio had requested 2 indents after `++` :-) `src/mem3/src/mem3_reshard_index.erl:80(56) - 123 - indentation does not increase two levels for trailing ++ operator` But I'll make it at the same level, I think it looks better that way. That is ``` abc() ++ def() ++ ghi(). ``` ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services
