Publish node metadata in a protected ets table This allows for far cheaper access to the zone information. The fallback to gen_server:calls is only for the initial hot upgrade and can be removed afterwards along with the code_change.
BugzID: 13606 Project: http://git-wip-us.apache.org/repos/asf/couchdb-mem3/repo Commit: http://git-wip-us.apache.org/repos/asf/couchdb-mem3/commit/f92f9cc6 Tree: http://git-wip-us.apache.org/repos/asf/couchdb-mem3/tree/f92f9cc6 Diff: http://git-wip-us.apache.org/repos/asf/couchdb-mem3/diff/f92f9cc6 Branch: refs/heads/import Commit: f92f9cc6ef0d46148a6bb76c62f894ca5f72387a Parents: 8ca5c51 Author: Adam Kocoloski <a...@cloudant.com> Authored: Mon May 21 21:32:22 2012 -0400 Committer: Adam Kocoloski <a...@cloudant.com> Committed: Wed May 23 17:07:03 2012 -0400 ---------------------------------------------------------------------- src/mem3_nodes.erl | 65 ++++++++++++++++++++++++++++++------------------- 1 file changed, 40 insertions(+), 25 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/couchdb-mem3/blob/f92f9cc6/src/mem3_nodes.erl ---------------------------------------------------------------------- diff --git a/src/mem3_nodes.erl b/src/mem3_nodes.erl index 460a006..454b5f9 100644 --- a/src/mem3_nodes.erl +++ b/src/mem3_nodes.erl @@ -22,37 +22,48 @@ -include("mem3.hrl"). -include_lib("couch/include/couch_db.hrl"). --record(state, {changes_pid, update_seq, nodes}). +-record(state, {changes_pid, update_seq}). start_link() -> gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). get_nodelist() -> - gen_server:call(?MODULE, get_nodelist). + try + lists:sort([N || {N,_} <- ets:tab2list(?MODULE)]) + catch error:badarg -> + gen_server:call(?MODULE, get_nodelist) + end. get_node_info(Node, Key) -> - gen_server:call(?MODULE, {get_node_info, Node, Key}). + try + couch_util:get_value(Key, ets:lookup_element(?MODULE, Node, 2)) + catch error:badarg -> + gen_server:call(?MODULE, {get_node_info, Node, Key}) + end. init([]) -> - {Nodes, UpdateSeq} = initialize_nodelist(), + ets:new(?MODULE, [named_table, {read_concurrency, true}]), + UpdateSeq = initialize_nodelist(), {Pid, _} = spawn_monitor(fun() -> listen_for_changes(UpdateSeq) end), - {ok, #state{changes_pid = Pid, update_seq = UpdateSeq, nodes = Nodes}}. + {ok, #state{changes_pid = Pid, update_seq = UpdateSeq}}. handle_call(get_nodelist, _From, State) -> - {reply, lists:sort(dict:fetch_keys(State#state.nodes)), State}; + {reply, lists:sort([N || {N,_} <- ets:tab2list(?MODULE)]), State}; handle_call({get_node_info, Node, Key}, _From, State) -> - case dict:find(Node, State#state.nodes) of - {ok, NodeInfo} -> - {reply, couch_util:get_value(Key, NodeInfo), State}; - error -> - {reply, error, State} - end; + Resp = try + couch_util:get_value(Key, ets:lookup_element(?MODULE, Node, 2)) + catch error:badarg -> + error + end, + {reply, Resp, State}; handle_call({add_node, Node, NodeInfo}, _From, #state{nodes=Nodes} = State) -> gen_event:notify(mem3_events, {add_node, Node}), - {reply, ok, State#state{nodes = dict:store(Node, NodeInfo, Nodes)}}; + ets:insert(?MODULE, Node, NodeInfo), + {reply, ok, State}; handle_call({remove_node, Node}, _From, #state{nodes=Nodes} = State) -> gen_event:notify(mem3_events, {remove_node, Node}), - {reply, ok, State#state{nodes = dict:erase(Node, Nodes)}}; + ets:delete(?MODULE, Node), + {reply, ok, State}; handle_call(_Call, _From, State) -> {noreply, State}. @@ -74,6 +85,10 @@ handle_info(_Info, State) -> terminate(_Reason, _State) -> ok. +code_change(_OldVsn, {state, ChangesPid, UpdateSeq, _}, _Extra) -> + ets:new(?MODULE, [named_table, {read_concurrency, true}]), + initialize_nodelist(), + {ok, #state{changes_pid = ChangesPid, update_seq = UpdateSeq}}; code_change(_OldVsn, State, _Extra) -> {ok, State}. @@ -82,27 +97,27 @@ code_change(_OldVsn, State, _Extra) -> initialize_nodelist() -> DbName = couch_config:get("mem3", "node_db", "nodes"), {ok, Db} = mem3_util:ensure_exists(DbName), - {ok, _, {_, Nodes0}} = couch_btree:fold(Db#db.id_tree, fun first_fold/3, - {Db, dict:new()}, []), + {ok, _, Db} = couch_btree:fold(Db#db.id_tree, fun first_fold/3, Db, []), % add self if not already present - case dict:find(node(), Nodes0) of - {ok, _} -> - Nodes = Nodes0; - error -> + case ets:lookup(?MODULE, node()) of + [_] -> + ok; + [] -> + ets:insert(?MODULE, {node(), []}), Doc = #doc{id = couch_util:to_binary(node())}, - {ok, _} = couch_db:update_doc(Db, Doc, []), - Nodes = dict:store(node(), [], Nodes0) + {ok, _} = couch_db:update_doc(Db, Doc, []) end, couch_db:close(Db), - {Nodes, Db#db.update_seq}. + Db#db.update_seq. first_fold(#full_doc_info{id = <<"_design/", _/binary>>}, _, Acc) -> {ok, Acc}; first_fold(#full_doc_info{deleted=true}, _, Acc) -> {ok, Acc}; -first_fold(#full_doc_info{id=Id}=DocInfo, _, {Db, Dict}) -> +first_fold(#full_doc_info{id=Id}=DocInfo, _, Db) -> {ok, #doc{body={Props}}} = couch_db:open_doc(Db, DocInfo), - {ok, {Db, dict:store(mem3_util:to_atom(Id), Props, Dict)}}. + ets:insert(?MODULE, {mem3_util:to_atom(Id), Props}), + {ok, Db}. listen_for_changes(Since) -> DbName = couch_config:get("mem3", "node_db", "nodes"),
