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-module(dbs_cache).
-behaviour(gen_server).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2,
code_change/3]).
-export([start_link/0]).
-include("membership.hrl").
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
init([]) ->
ets:new(partitions, [bag, protected, named_table, {keypos,#shard.dbname}]),
ets:new(memnodes, [bag, protected, named_table]),
cache_dbs(),
Self = self(),
couch_db_update_notifier:start_link(fun({updated, <<"dbs">>}) ->
Self ! rebuild_dbs_cache;
(_) -> ok end),
{ok, nil}.
handle_call(_Msg, _From, State) ->
{reply, ok, State}.
handle_cast(_Msg, State) ->
{noreply, State}.
handle_info(rebuild_dbs_cache, State) ->
receive rebuild_dbs_cache ->
handle_info(rebuild_dbs_cache, State)
after 0 -> ok end,
T0 = now(),
?LOG_INFO("rebuilding dbs DB cache", []),
ets:delete_all_objects(partitions),
ets:delete_all_objects(memnodes),
cache_dbs(),
?LOG_INFO("rebuild of dbs DB cache complete in ~p ms",
[round(timer:now_diff(now(),T0)/1000)]),
{noreply, State}.
terminate(_Reason, _State) ->
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
cache_dbs() ->
try couch_db:open(<<"dbs">>, []) of
{ok, Db} ->
Bt = Db#db.id_tree,
FoldFun = fun(#full_doc_info{id=Id, deleted=false} = FullDocInfo, _, _) ->
{ok, Doc} = couch_db:open_doc_int(Db, FullDocInfo, []),
{Props} = couch_doc:to_json_obj(Doc, []),
cache_map(Id, Props),
cache_nodes(Id, Props),
{ok, true};
(_, _, _) ->
{ok, nil}
end,
couch_btree:foldl(Bt, FoldFun, nil),
couch_db:close(Db)
catch exit:{noproc,{gen_server,call,[couch_server|_]}} ->
timer:sleep(1000),
exit(couch_server_is_dead)
end.
cache_map(Id, Props) ->
Map = couch_util:get_value(<<"map">>, Props),
lists:foreach(fun({[{<<"node">>,Node},{<<"b">>,Beg},{<<"e">>,End}]}) ->
Part = #shard{
name = partitions:shard_name(Beg, Id),
dbname = Id,
node = to_atom(Node),
range = [Beg,End]
},
ets:insert(partitions, Part)
end, Map).
cache_nodes(Id, Props) ->
Nodes = couch_util:get_value(<<"nodes">>, Props),
lists:foreach(fun({[{<<"order">>,Order},{<<"node">>, Node},{<<"options">>,Opts}]}) ->
ets:insert(memnodes, {Id, {Order, to_atom(Node), Opts}})
end, Nodes).
to_atom(Node) when is_binary(Node) ->
list_to_atom(binary_to_list(Node));
to_atom(Node) when is_atom(Node) ->
Node.
%{ok, ets:insert(dbs_cache, {Id, Props})};
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