wip: add POST /db/_max_generation

Author: jcoglan

src/chttpd/src/chttpd_db.erl

@@ -855,6 +855,19 @@ db_req(#httpd{method = 'GET', path_parts = [_, <<"_revs_limit">>]} = Req, Db) ->
     send_json(Req, fabric:get_revs_limit(Db));
 db_req(#httpd{path_parts = [_, <<"_revs_limit">>]} = Req, _Db) ->
     send_method_not_allowed(Req, "PUT,GET");
+db_req(#httpd{method = 'PUT', path_parts = [_, <<"_max_generation">>]} = Req, Db) ->
+    Options = [{user_ctx, Req#httpd.user_ctx}],
+    case chttpd:json_body(Req) of
+        MaxGen when is_integer(MaxGen), MaxGen > 0 ->
+            case fabric:set_max_generation(Db, MaxGen, Options) of
+                ok ->
+                    send_json(Req, {[{<<"ok">>, true}]});
+                Error ->
+                    throw(Error)
+            end;
+        _ ->
+            throw({bad_request, "`max_generation` must be positive integer"})
+    end;
 db_req(#httpd{method = 'PUT', path_parts = [_, <<"_purged_infos_limit">>]} = Req, Db) ->
     Options = [{user_ctx, Req#httpd.user_ctx}],
     case chttpd:json_body(Req) of

src/couch/src/couch_bt_engine.erl

@@ -49,6 +49,7 @@
     get_uuid/1,
 
     set_revs_limit/2,
+    set_max_generation/2,
     set_purge_infos_limit/2,
     set_security/2,
     set_props/2,
@@ -388,6 +389,17 @@ set_revs_limit(#st{header = Header} = St, RevsLimit) ->
     },
     {ok, increment_update_seq(NewSt)}.
 
+set_max_generation(#st{filepath = FilePath, gen_fds = GenFds, header = Header} = St, MaxGen) ->
+    NewSt = St#st{
+        header = couch_bt_engine_header:set(Header, [
+            {max_generation, MaxGen}
+        ]),
+        needs_commit = true
+    },
+    GenFds1 = open_missing_generation_files(FilePath, GenFds, MaxGen),
+    NewSt1 = NewSt#st{gen_fds = GenFds1},
+    {ok, increment_update_seq(NewSt1)}.
+
 set_purge_infos_limit(#st{header = Header} = St, PurgeInfosLimit) ->
     NewSt = St#st{
         header = couch_bt_engine_header:set(Header, [
@@ -982,6 +994,18 @@ open_generation_files(FilePath, Generations, Options) ->
         lists:seq(1, Generations)
     ).
 
+open_missing_generation_files(FilePath, GenFds, MaxGen) ->
+    open_missing_generation_files(FilePath, GenFds, MaxGen, 1).
+
+open_missing_generation_files(FilePath, GenFds, MaxGen, Gen) when Gen > MaxGen ->
+    GenFds;
+open_missing_generation_files(FilePath, [], MaxGen, Gen) ->
+    Rest = open_missing_generation_files(FilePath, [], MaxGen, Gen + 1),
+    Fd = open_generation_file(FilePath, Gen, []),
+    [Fd | Rest];
+open_missing_generation_files(FilePath, [Fd | Rest], MaxGen, Gen) ->
+    [Fd | open_missing_generation_files(FilePath, Rest, MaxGen, Gen + 1)].
+
 maybe_open_generation_files(FilePath, Generations, Options) ->
     case lists:member(compacting, Options) of
         true -> [];

src/couch/src/couch_db.erl

@@ -63,6 +63,7 @@
     is_partitioned/1,
 
     set_revs_limit/2,
+    set_max_generation/2,
     set_purge_infos_limit/2,
     set_security/2,
     set_user_ctx/2,
@@ -540,6 +541,12 @@ purge_client_exists(DbName, DocId, Props) ->
             true
     end.
 
+set_max_generation(#db{main_pid = Pid} = Db, MaxGen) when MaxGen > 0 ->
+    check_is_admin(Db),
+    gen_server:call(Pid, {set_max_generation, MaxGen}, infinity);
+set_max_generation(_Db, _MaxGen) ->
+    throw(invalid_purge_infos_limit).
+
 set_purge_infos_limit(#db{main_pid = Pid} = Db, Limit) when Limit > 0 ->
     check_is_admin(Db),
     gen_server:call(Pid, {set_purge_infos_limit, Limit}, infinity);

src/couch/src/couch_db_engine.erl

@@ -276,6 +276,9 @@
 -callback set_revs_limit(DbHandle :: db_handle(), RevsLimit :: pos_integer()) ->
     {ok, NewDbHandle :: db_handle()}.
 
+-callback set_max_generation(DbHandle :: db_handle(), MaxGen :: pos_integer()) ->
+    {ok, NewDbHandle :: db_handle()}.
+
 -callback set_purge_infos_limit(DbHandle :: db_handle(), Limit :: pos_integer()) ->
     {ok, NewDbHandle :: db_handle()}.
 
@@ -685,6 +688,7 @@
 
     set_revs_limit/2,
     set_security/2,
+    set_max_generation/2,
     set_purge_infos_limit/2,
     set_props/2,
 
@@ -851,6 +855,11 @@ set_revs_limit(#db{} = Db, RevsLimit) ->
     {ok, NewSt} = Engine:set_revs_limit(EngineState, RevsLimit),
     {ok, Db#db{engine = {Engine, NewSt}}}.
 
+set_max_generation(#db{} = Db, MaxGen) ->
+    #db{engine = {Engine, EngineState}} = Db,
+    {ok, NewSt} = Engine:set_max_generation(EngineState, MaxGen),
+    {ok, Db#db{engine = {Engine, NewSt}}}.
+
 set_purge_infos_limit(#db{} = Db, PurgedDocsLimit) ->
     #db{engine = {Engine, EngineState}} = Db,
     {ok, NewSt} = Engine:set_purge_infos_limit(EngineState, PurgedDocsLimit),

src/couch/src/couch_db_updater.erl

@@ -89,6 +89,10 @@ handle_call({set_revs_limit, Limit}, _From, Db) ->
     Db3 = commit_data(Db2),
     ok = couch_server:db_updated(Db3),
     {reply, ok, Db3};
+handle_call({set_max_generation, MaxGen}, _From, Db) ->
+    {ok, Db2} = couch_db_engine:set_max_generation(Db, MaxGen),
+    ok = couch_server:db_updated(Db2),
+    {reply, ok, Db2};
 handle_call({set_purge_infos_limit, Limit}, _From, Db) ->
     {ok, Db2} = couch_db_engine:set_purge_infos_limit(Db, Limit),
     ok = couch_server:db_updated(Db2),

src/fabric/src/fabric.erl

@@ -29,6 +29,7 @@
     get_revs_limit/1,
     get_security/1, get_security/2,
     get_all_security/1, get_all_security/2,
+    set_max_generation/3,
     get_purge_infos_limit/1,
     set_purge_infos_limit/3,
     get_purged_infos/1,
@@ -185,6 +186,13 @@ set_security(DbName, SecObj) ->
 set_security(DbName, SecObj, Options) ->
     fabric_db_meta:set_security(dbname(DbName), SecObj, opts(Options)).
 
+%% @doc sets the upper bound for the number of storage generations
+-spec set_max_generation(dbname(), pos_integer(), [option()]) -> ok.
+set_max_generation(DbName, MaxGen, Options) when
+    is_integer(MaxGen), MaxGen > 0
+->
+    fabric_db_meta:set_max_generation(dbname(DbName), MaxGen, opts(Options)).
+
 %% @doc sets the upper bound for the number of stored purge requests
 -spec set_purge_infos_limit(dbname(), pos_integer(), [option()]) -> ok.
 set_purge_infos_limit(DbName, Limit, Options) when

src/fabric/src/fabric_db_meta.erl

@@ -16,6 +16,7 @@
     set_revs_limit/3,
     set_security/3,
     get_all_security/2,
+    set_max_generation/3,
     set_purge_infos_limit/3
 ]).
 
@@ -51,6 +52,21 @@ handle_revs_message(ok, Worker, {Workers, Waiting}) ->
 handle_revs_message(Error, _, _Acc) ->
     {error, Error}.
 
+set_max_generation(DbName, MaxGen, Options) ->
+    Shards = mem3:shards(DbName),
+    Workers = fabric_util:submit_jobs(Shards, set_max_generation, [MaxGen, Options]),
+    Handler = fun handle_purge_message/3,
+    Acc0 = {Workers, length(Workers) - 1},
+    case fabric_util:recv(Workers, #shard.ref, Handler, Acc0) of
+        {ok, ok} ->
+            ok;
+        {timeout, {DefunctWorkers, _}} ->
+            fabric_util:log_timeout(DefunctWorkers, "set_purged_docs_limit"),
+            {error, timeout};
+        Error ->
+            Error
+    end.
+
 set_purge_infos_limit(DbName, Limit, Options) ->
     Shards = mem3:shards(DbName),
     Workers = fabric_util:submit_jobs(Shards, set_purge_infos_limit, [Limit, Options]),

src/fabric/src/fabric_rpc.erl

@@ -39,7 +39,9 @@
 ]).
 -export([get_all_security/2, open_shard/2]).
 -export([compact/1, compact/2]).
--export([get_purge_seq/2, get_purged_infos/1, purge_docs/3, set_purge_infos_limit/3]).
+-export([
+    get_purge_seq/2, get_purged_infos/1, purge_docs/3, set_max_generation/3, set_purge_infos_limit/3
+]).
 
 -export([
     get_db_info/2,
@@ -259,6 +261,9 @@ get_all_security(DbName, Options) ->
 set_revs_limit(DbName, Limit, Options) ->
     with_db(DbName, Options, {couch_db, set_revs_limit, [Limit]}).
 
+set_max_generation(DbName, MaxGen, Options) ->
+    with_db(DbName, Options, {couch_db, set_max_generation, [MaxGen]}).
+
 set_purge_infos_limit(DbName, Limit, Options) ->
     with_db(DbName, Options, {couch_db, set_purge_infos_limit, [Limit]}).
 

t.sh

@@ -20,6 +20,23 @@ test_doc_with_att_compact () {
   check-files 'OBVIOUS ATTACHMENT'  0 1
 }
 
+test_max_gen_upgrade () {
+  create-db 0
+
+  create-doc 'the-doc' '{ "basic": "DOC BODY" }'
+  add-att 'the-doc' 'the-att' 'VERY OBVIOUS ATTACHMENT DATA'
+  compact 0
+
+  check-files 'DOC BODY'            1
+  check-files 'OBVIOUS ATTACHMENT'  1
+
+  cdb '/asd/_max_generation' -X PUT -d '2'
+  compact 0
+
+  check-files 'DOC BODY'            0 1
+  check-files 'OBVIOUS ATTACHMENT'  0 1
+}
+
 test_doc_compact_add_att () {
   create-doc 'the-doc' '{ "basic": "DOC BODY" }'
   compact 0