* src/ejabberd_rdbms.erl: fix SQL database reconnection

issues (EJAB-764) and add odbc_start_interval configuration
directive (default to 30 seconds).
* src/odbc/ejabberd_odbc.erl: likewise.
* src/odbc/ejabberd_odbc_sup.erl: likewise.
* doc/guide.tex: likewise.

SVN Revision: 1600

ChangeLog

@@ -1,3 +1,12 @@
+2008-10-06  Jerome Sautret  <jerome.sautret@process-one.net>
+
+	* src/ejabberd_rdbms.erl: fix SQL database reconnection
+	issues (EJAB-764) and add odbc_start_interval configuration
+	directive (default to 30 seconds).
+	* src/odbc/ejabberd_odbc.erl: likewise.
+	* src/odbc/ejabberd_odbc_sup.erl: likewise.
+	* doc/guide.tex: likewise.
+
 2008-10-03  Jerome Sautret  <jerome.sautret@process-one.net>
 
 	* src/odbc/odbc_queries.erl: Fix empty query that fail on MySQL.

doc/guide.tex

@@ -1617,6 +1617,13 @@ Specify in seconds: for example 28800 means 8 hours.
 {odbc_keepalive_interval, undefined}.
 \end{verbatim}
 
+If the connection to the database fails, \ejabberd{} waits 30 seconds before retrying.
+You can modify this interval with this option:
+\begin{verbatim}
+{odbc_start_interval, 30}.
+\end{verbatim}
+
+
 \makesubsubsection{compilemysql}{Driver Compilation}
 \ind{MySQL!Driver Compilation}
 

src/ejabberd_rdbms.erl

@@ -52,14 +52,21 @@ start_hosts() ->
 
 %% Start the ODBC module on the given host
 start_odbc(Host) ->
+    Supervisor_name = gen_mod:get_module_proc(Host, ejabberd_odbc_sup),
     ChildSpec =
-	{gen_mod:get_module_proc(Host, ejabberd_odbc_sup),
+	{Supervisor_name,
 	 {ejabberd_odbc_sup, start_link, [Host]},
-	 temporary,
+	 transient,
 	 infinity,
 	 supervisor,
 	 [ejabberd_odbc_sup]},
-    supervisor:start_child(ejabberd_sup, ChildSpec).
+    case supervisor:start_child(ejabberd_sup, ChildSpec) of
+	{ok, _PID} ->
+	    ok;
+	_Error ->
+	    ?ERROR_MSG("Start of supervisor ~p failed:~n~p~nRetrying...~n", [Supervisor_name, _Error]),
+	    start_odbc(Host)
+    end.
 
 %% Returns true if we have configured odbc_server for the given host
 needs_odbc(Host) ->

src/odbc/ejabberd_odbc.erl

@@ -30,7 +30,7 @@
 -behaviour(gen_server).
 
 %% External exports
--export([start/1, start_link/1,
+-export([start/1, start_link/2,
 	 sql_query/2,
 	 sql_query_t/1,
 	 sql_transaction/2,
@@ -63,8 +63,8 @@
 start(Host) ->
     gen_server:start(ejabberd_odbc, [Host], []).
 
-start_link(Host) ->
+start_link(Host, StartInterval) ->
-    gen_server:start_link(ejabberd_odbc, [Host], []).
+    gen_server:start_link(ejabberd_odbc, [Host, StartInterval], []).
 
 sql_query(Host, Query) ->
     gen_server:call(ejabberd_odbc_sup:get_random_pid(Host),
@@ -131,10 +131,10 @@ escape_like(C)  -> odbc_queries:escape(C).
 %%          ignore               |
 %%          {stop, Reason}
 %%----------------------------------------------------------------------
-init([Host]) ->
+init([Host, StartInterval]) ->
     case ejabberd_config:get_local_option({odbc_keepalive_interval, Host}) of
-	Interval when is_integer(Interval) ->
+	KeepaliveInterval when is_integer(KeepaliveInterval) ->
-	    timer:apply_interval(Interval*1000, ?MODULE, keep_alive, [self()]);
+	    timer:apply_interval(KeepaliveInterval*1000, ?MODULE, keep_alive, [self()]);
 	undefined ->
 	    ok;
 	_Other ->
@@ -144,16 +144,16 @@ init([Host]) ->
     case SQLServer of
 	%% Default pgsql port
 	{pgsql, Server, DB, Username, Password} ->
-	    pgsql_connect(Server, ?PGSQL_PORT, DB, Username, Password);
+	    pgsql_connect(Server, ?PGSQL_PORT, DB, Username, Password, StartInterval);
 	{pgsql, Server, Port, DB, Username, Password} when is_integer(Port) ->
-	    pgsql_connect(Server, Port, DB, Username, Password);
+	    pgsql_connect(Server, Port, DB, Username, Password, StartInterval);
 	%% Default mysql port
 	{mysql, Server, DB, Username, Password} ->
-	    mysql_connect(Server, ?MYSQL_PORT, DB, Username, Password);
+	    mysql_connect(Server, ?MYSQL_PORT, DB, Username, Password, StartInterval);
 	{mysql, Server, Port, DB, Username, Password} when is_integer(Port) ->
-	    mysql_connect(Server, Port, DB, Username, Password);
+	    mysql_connect(Server, Port, DB, Username, Password, StartInterval);
 	_ when is_list(SQLServer) ->
-	    odbc_connect(SQLServer)
+	    odbc_connect(SQLServer, StartInterval)
     end.
 
 %%----------------------------------------------------------------------
@@ -259,7 +259,7 @@ execute_transaction(State, F, NRestarts) ->
 
 %% part of init/1
 %% Open an ODBC database connection
-odbc_connect(SQLServer) ->
+odbc_connect(SQLServer, StartInterval) ->
     application:start(odbc),
     case odbc:connect(SQLServer,[{scrollable_cursors, off}]) of
 	{ok, Ref} ->
@@ -268,8 +268,8 @@ odbc_connect(SQLServer) ->
 	{error, Reason} ->
 	    ?ERROR_MSG("ODBC connection (~s) failed: ~p~n",
 		       [SQLServer, Reason]),
-	    %% If we can't connect we wait for 30 seconds before retrying
+	    %% If we can't connect we wait before retrying
-	    timer:sleep(30000),
+	    timer:sleep(StartInterval),
 	    {stop, odbc_connection_failed}
     end.
 
@@ -278,15 +278,15 @@ odbc_connect(SQLServer) ->
 
 %% part of init/1
 %% Open a database connection to PostgreSQL
-pgsql_connect(Server, Port, DB, Username, Password) ->
+pgsql_connect(Server, Port, DB, Username, Password, StartInterval) ->
     case pgsql:connect(Server, DB, Username, Password, Port) of
 	{ok, Ref} ->
 	    erlang:monitor(process, Ref),
 	    {ok, #state{db_ref = Ref, db_type = pgsql}};
 	{error, Reason} ->
 	    ?ERROR_MSG("PostgreSQL connection failed: ~p~n", [Reason]),
-	    %% If we can't connect we wait for 30 seconds before retrying
+	    %% If we can't connect we wait before retrying
-	    timer:sleep(30000),
+	    timer:sleep(StartInterval),
 	    {stop, pgsql_connection_failed}
     end.
 
@@ -317,7 +317,7 @@ pgsql_item_to_odbc(_) ->
 
 %% part of init/1
 %% Open a database connection to MySQL
-mysql_connect(Server, Port, DB, Username, Password) ->
+mysql_connect(Server, Port, DB, Username, Password, StartInterval) ->
     NoLogFun = fun(_Level,_Format,_Argument) -> ok end,
     case mysql_conn:start(Server, Port, Username, Password, DB, NoLogFun) of
 	{ok, Ref} ->
@@ -330,9 +330,10 @@ mysql_connect(Server, Port, DB, Username, Password) ->
 				   "SERIALIZABLE;"], self()),
 	    {ok, #state{db_ref = Ref, db_type = mysql}};
 	{error, Reason} ->
-	    ?ERROR_MSG("MySQL connection failed: ~p~n", [Reason]),
+	    ?ERROR_MSG("MySQL connection failed: ~p~nWaiting ~p seconds before retrying...~n",
-	    %% If we can't connect we wait for 30 seconds before retrying
+		       [Reason, StartInterval div 1000]),
-	    timer:sleep(30000),
+	    %% If we can't connect we wait before retrying
+	    timer:sleep(StartInterval),
 	    {stop, mysql_connection_failed}
     end.
 

src/odbc/ejabberd_odbc_sup.erl

@@ -37,32 +37,44 @@
 -include("ejabberd.hrl").
 
 -define(DEFAULT_POOL_SIZE, 10).
+-define(DEFAULT_ODBC_START_INTERVAL, 30). % 30 seconds
 
 start_link(Host) ->
     supervisor:start_link({local, gen_mod:get_module_proc(Host, ?MODULE)},
 			  ?MODULE, [Host]).
 
 init([Host]) ->
-    N = case ejabberd_config:get_local_option({odbc_pool_size, Host}) of
+    PoolSize = case ejabberd_config:get_local_option({odbc_pool_size, Host}) of
-	    I when is_integer(I) ->
+		   I when is_integer(I) ->
-		I;
+		       I;
 	    undefined ->
-		?DEFAULT_POOL_SIZE;
+		       ?DEFAULT_POOL_SIZE;
-	    Other ->
+		   Other ->
-		?ERROR_MSG("Wrong odbc_pool_size definition '~p' for host ~p, default to ~p~n",
+		       ?ERROR_MSG("Wrong odbc_pool_size definition '~p' for host ~p, default to ~p~n",
-			   [Other, Host, ?DEFAULT_POOL_SIZE]),
+				  [Other, Host, ?DEFAULT_POOL_SIZE]),
-		?DEFAULT_POOL_SIZE
+		       ?DEFAULT_POOL_SIZE
-	end,
+	       end,
-    {ok, {{one_for_one, 10, 6},
+    StartInterval = case ejabberd_config:get_local_option({odbc_start_interval, Host}) of
+			Interval when is_integer(Interval) ->
+			    Interval;
+			undefined ->
+			    ?DEFAULT_ODBC_START_INTERVAL;
+			_Other2 ->
+			    ?ERROR_MSG("Wrong odbc_start_interval definition '~p' for host ~p"
+				       ", defaulting to ~p~n",
+				       [_Other2, Host, ?DEFAULT_ODBC_START_INTERVAL]),
+			    ?DEFAULT_ODBC_START_INTERVAL
+		    end,
+    {ok, {{one_for_one, PoolSize+1, StartInterval},
 	  lists:map(
 	    fun(I) ->
 		    {I,
-		     {ejabberd_odbc, start_link, [Host]},
+		     {ejabberd_odbc, start_link, [Host, StartInterval*1000]},
 		     transient,
 		     brutal_kill,
 		     worker,
 		     [?MODULE]}
-	    end, lists:seq(1, N))}}.
+	    end, lists:seq(1, PoolSize))}}.
 
 get_pids(Host) ->
     Proc = gen_mod:get_module_proc(Host, ?MODULE),