erlang r19里面的mnesia_ext
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r19据说支持了mnesia_ext,终于可以给那个恶心2gb limit的mnesia换存储引擎了
先下载r19源码,编译
./otp_build all -a ~/dev/erlang/r19
./Install ~/dev/erlang/r19
关于mnesia_ext,r19说是有了,但是怎么做,没有文档,也没有资料,最后在otp的pull request里面找
https://github.com/erlang/otp/pull/858/files
看到create_schema,发现有两个参数了,看来似乎是有了,但是怎么写呢
再次google mnesia_ext,找到下面这个
https://github.com/klarna/mnesia_pg
搜索
grep -nr "mnesia:create_schema" ./
看到
mnesia:create_schema([node()], [{backend_types, [{pg, mnesia_pg}]}]),
然后去mnesia_pg里面看了下,貌似有个
-behaviour(mnesia_backend_type).
那我们直接在r19里面搜索
grep -nr "module(mnesia_backend_type)" ./
ok,找到了
mnesia_backend_type.erl
%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 1996-2015. All Rights Reserved. %% %% 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. %% %% %CopyrightEnd% %% %% %% Behaviour definition for mnesia backend types. %% %%%header_doc_include -module(mnesia_backend_type). -export([behaviour_info/1]). %%%header_doc_include %%%impl_doc_include %% Note that mnesia considers all callbacks mandatory!! %% behaviour_info(callbacks) -> [ {add_aliases, 1}, % (Aliases) -> ok {check_definition, 4}, % (TypeAlias, Tab, Nodes, Properties) -> ok {close_table, 2}, % (TypeAlias, Tab) -> ok {create_table, 3}, % (TypeAlias, Tab, Properties) -> ok {delete, 3}, % (TypeAlias, Tab, Key) -> true | ok {delete_table, 2}, % (TypeAlias, Tab) -> ok {first, 2}, % (TypeAlias, Tab) -> Key::Term | ‘$end_of_table‘ {fixtable, 3}, % (TypeAlias, Tab, Bool) -> ok | true {last, 2}, % (TypeAlias, Tab) -> Key::Term | ‘$end_of_table‘ {index_is_consistent,3}, % (TypeAlias, IxTag, Bool) -> ok {init_backend, 0}, % () -> ok {info, 3}, % (TypeAlias, Tab, Item) -> Term {insert, 3}, % (TypeAlias, Tab, Object) -> ok {lookup, 3}, % (TypeAlias, Tab, Key) -> [Objects] {is_index_consistent,2}, % (TypeAlias, IxTag) -> Bool {load_table, 4}, % (TypeAlias, Tab, Reason, CsList) -> ok {match_delete, 3}, % (TypeAlias, Tab, Pattern) -> ok {next, 3}, % (TypeAlias, Tab, Key) -> Key::Term | ‘$end_of_table‘ {prev, 3}, % (TypeAlias, Tab, Key) -> Key::Term | ‘$end_of_table‘ {receiver_first_message, 4}, % (Sender, FirstMsg, Alias, Tab) -> {Size, State} {receive_data, 5}, % (Data, Alias, Name, Sender, State) -> {more, State} | {{more, Msg}, State} {receive_done, 4}, % (Alias, Tab, Sender, State) -> ok {real_suffixes, 0}, % () -> [FileSuffix] {remove_aliases, 1}, % (Aliases) -> ok {repair_continuation, 2}, % (Continuation, MatchSpec) -> Continuation {select, 1}, % (Continuation) -> {[Match], Continuation‘} | ‘$end_of_table‘ {select, 3}, % (TypeAlias, Tab, Pattern) -> {[Match], Continuation‘} | ‘$end_of_table‘ {select, 4}, % (TypeAlias, Tab, MatchSpec, Limit) {[Match], Continuation‘} | ‘$end_of_table‘ {sender_init, 4}, % (TypeAlias, Tab, LoadReason, Pid) -> % {standard, Init(), Chunk()} | {Init(), Chunk()} {semantics, 2}, % (TypeAlias, storage | types | index_fun | index_types) -> % ram_copies | disc_copies, set | ordered_set | bag, fun(), ordered | bag {slot, 3}, % (TypeAlias, Tab, Pos) -> ‘$end_of_table‘ | Objects | {error, Reason} {sync_close_table, 2}, % (TypeAlias, Tab) -> ok {tmp_suffixes, 0}, % () -> [FileSuffix] {update_counter, 4}, % (TypeAlias, Tab, Counter, Val) -> NewVal {validate_key, 6}, % (TypeAlias, Tab, RecName, Arity, Type, Key) -> {RecName, Arity, Type} {validate_record, 6} % (TypeAlias, Tab, RecName, Arity, Type, Obj) -> {RecName, Arity, Type} ]. %%%impl_doc_include %% -type tab() :: atom(). %% -type alias() :: atom(). %% -type rec_name() :: atom(). %% -type type() :: set | bag | ordered_set. %% -type proplist() :: [{atom(), any()}]. %% -type key() :: any(). %% -type db_object() :: tuple(). %% -type matchspec() :: ets:match_spec(). %% -type limit() :: integer() | infinity. %% -type cont_fun() :: any(). %% -type cont() :: ‘$end_of_table‘ | cont_fun(). %% -callback check_definition(alias(), tab(), [node()], proplist()) -> ok. %% -callback create_table(alias(), tab(), proplist()) -> tab(). %% -callback load_table(alias(), tab(), any()) -> ok. %% -callback delete_table(alias(), tab()) -> ok. %% -callback first(alias(), tab()) -> key(). %% -callback last(alias(), tab()) -> key(). %% -callback next(alias(), tab(), key()) -> key(). %% -callback prev(alias(), tab(), key()) -> key(). %% -callback insert(alias(), tab(), db_object()) -> ok. %% -callback lookup(alias(), tab(), key()) -> [db_object()]. %% -callback delete(alias(), tab(), key()) -> ok. %% -callback update_counter(alias(), tab(), key(), integer()) -> integer(). %% -callback select(cont()) -> {list(), cont()}. %% -callback select(alias(), tab(), matchspec()) -> list() | ‘$end_of_table‘. %% -callback select(alias(), tab(), matchspec(), limit()) -> {list(), cont()}. %% -callback slot(alias(), tab(), integer()) -> key(). %% -callback validate_key(alias(), tab(), rec_name(), arity(), type(), key()) -> %% {rec_name(), arity(), type()}. %% -callback validate_record(alias(),tab(),rec_name(),arity(),type(),db_obj()) -> %% {rec_name(), arity(), type()}. %% -callback repair_continuation(cont(), matchspec()) -> cont().
应该就是这些了吧,具体的和后端存储引擎的对接,还是等大牛吧。
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