| % 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. |
| |
| |
| % Maintain cluster membership and stability notifications for replications. |
| % On changes to cluster membership, broadcast events to `replication` gen_event. |
| % Listeners will get `{cluster, stable}` or `{cluster, unstable}` events. |
| % |
| % Cluster stability is defined as "there have been no nodes added or removed in |
| % last `QuietPeriod` seconds". QuietPeriod value is configurable. To ensure a |
| % speedier startup, during initialization there is a shorter StartupQuietPeriod |
| % in effect (also configurable). |
| % |
| % This module is also in charge of calculating ownership of replications based |
| % on where their _repicator db documents shards live. |
| |
| -module(couch_replicator_rate_limiter_tables). |
| |
| -export([ |
| create/1, |
| tids/0, |
| term_to_table/1 |
| ]). |
| |
| -define(SHARDS_N, 16). |
| |
| |
| -spec create(non_neg_integer()) -> ok. |
| create(KeyPos) -> |
| Opts = [named_table, public, {keypos, KeyPos}, {read_concurrency, true}], |
| [ets:new(list_to_atom(TableName), Opts) || TableName <- table_names()], |
| ok. |
| |
| |
| -spec tids() -> [atom()]. |
| tids() -> |
| [list_to_existing_atom(TableName) || TableName <- table_names()]. |
| |
| |
| -spec term_to_table(any()) -> atom(). |
| term_to_table(Term) -> |
| PHash = erlang:phash2(Term), |
| list_to_existing_atom(table_name(PHash rem ?SHARDS_N)). |
| |
| |
| -spec table_names() -> [string()]. |
| table_names() -> |
| [table_name(N) || N <- lists:seq(0, ?SHARDS_N - 1)]. |
| |
| |
| -spec table_name(non_neg_integer()) -> string(). |
| table_name(Id) when is_integer(Id), Id >= 0 andalso Id < ?SHARDS_N -> |
| atom_to_list(?MODULE) ++ "_" ++ integer_to_list(Id). |