mod_mam_mnesia: Don't exceed table size limit

Don't write MAM messages into an Mnesia archive if the size of the table
comes close to the 2 GB limit for tables with disc-only copies.  That
way, the table is at least not corrupted when the limit is reached.

diff --git a/src/mod_mam_mnesia.erl b/src/mod_mam_mnesia.erl
index 1e1f20c9ada6ad92e0cb54c109cd9758f1921bee..225d1c4ce298aca3611c53509fff5ee02c2a46b1 100644 (file)
--- a/src/mod_mam_mnesia.erl
+++ b/src/mod_mam_mnesia.erl
@@ -26,6 +26,8 @@
        ((A < B andalso byte_size(A) == byte_size(B))
         orelse byte_size(A) < byte_size(B))).
 
+-define(TABLE_SIZE_LIMIT, 2000000000). % A bit less than 2 GiB.
+
 %%%===================================================================
 %%% API
 %%%===================================================================
@@ -83,26 +85,35 @@ extended_fields() ->
     [].
 
 store(Pkt, _, {LUser, LServer}, Type, Peer, Nick, _Dir) ->
-    LPeer = {PUser, PServer, _} = jid:tolower(Peer),
-    TS = p1_time_compat:timestamp(),
-    ID = jlib:integer_to_binary(now_to_usec(TS)),
-    F = fun() ->
-               mnesia:write(#archive_msg{us = {LUser, LServer},
-                                         id = ID,
-                                         timestamp = TS,
-                                         peer = LPeer,
-                                         bare_peer = {PUser, PServer, <<>>},
-                                         type = Type,
-                                         nick = Nick,
-                                         packet = Pkt})
-       end,
-    case mnesia:transaction(F) of
-       {atomic, ok} ->
-           {ok, ID};
-       {aborted, Err} ->
-           ?ERROR_MSG("Cannot add message to MAM archive of ~s@~s: ~s",
-                      [LUser, LServer, Err]),
-           Err
+    case {mnesia:table_info(archive_msg, disc_only_copies),
+         mnesia:table_info(archive_msg, memory)} of
+       {[_|_], TableSize} when TableSize > ?TABLE_SIZE_LIMIT ->
+           ?ERROR_MSG("MAM archive of ~s@~s too large, won't store message",
+                      [LUser, LServer]),
+           {error, overflow};
+       _ ->
+           LPeer = {PUser, PServer, _} = jid:tolower(Peer),
+           TS = p1_time_compat:timestamp(),
+           ID = jlib:integer_to_binary(now_to_usec(TS)),
+           F = fun() ->
+                       mnesia:write(
+                         #archive_msg{us = {LUser, LServer},
+                                      id = ID,
+                                      timestamp = TS,
+                                      peer = LPeer,
+                                      bare_peer = {PUser, PServer, <<>>},
+                                      type = Type,
+                                      nick = Nick,
+                                      packet = Pkt})
+               end,
+           case mnesia:transaction(F) of
+               {atomic, ok} ->
+                   {ok, ID};
+               {aborted, Err} ->
+                   ?ERROR_MSG("Cannot add message to MAM archive of ~s@~s: ~s",
+                              [LUser, LServer, Err]),
+                   Err
+           end
     end.
 
 write_prefs(_LUser, _LServer, Prefs, _ServerHost) ->