Merge branch 'is/mnesia-send-compressed' into ccase/r13b04_dev

* is/mnesia-send-compressed:
  Add option to compress data when copying tables between Mnesia nodes

OTP-8406  Igor Ribeiro Sucupira added the option to compress data when
          copying tables between Mnesia nodes.

4 files changed, 71 insertions, 23 deletions

diff --git a/lib/mnesia/doc/src/mnesia.xml b/lib/mnesia/doc/src/mnesia.xml
index 3484cd104a..07f9fce8c7 100644
--- a/lib/mnesia/doc/src/mnesia.xml
+++ b/lib/mnesia/doc/src/mnesia.xml
@@ -4,7 +4,7 @@
 <erlref>
   <header>
     <copyright>
-      <year>1996</year><year>2009</year>
+      <year>1996</year><year>2010</year>
       <holder>Ericsson AB. All Rights Reserved.</holder>
     </copyright>
     <legalnotice>
@@ -13,12 +13,12 @@
       compliance with the License. You should have received a copy of the
       Erlang Public License along with this software. If not, it can be
       retrieved online at http://www.erlang.org/.
-    
+
       Software distributed under the License is distributed on an "AS IS"
       basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
       the License for the specific language governing rights and limitations
       under the License.
-    
+
     </legalnotice>
 
     <title>mnesia</title>
@@ -3045,6 +3045,17 @@ raise(Name, Amount) ->
           </p>
       </item>
       <item>
+        <p><c>-mnesia send_compressed Level</c> specifies the level of
+          compression to be used when copying a table from the local node to
+          another one. The default level is 0.
+          </p>
+        <p><c>Level</c> must be an integer in the interval [0, 9], with 0
+          representing no compression and 9 representing maximum compression.
+          Before setting it to a non-zero value, make sure the remote nodes
+          understand this configuration.
+          </p>
+      </item>
+      <item>
         <p><c>-mnesia schema_location Loc</c> controls where
           Mnesia will look for its schema. The parameter
           <c>Loc</c> may be one of the following atoms: </p>
diff --git a/lib/mnesia/src/mnesia.erl b/lib/mnesia/src/mnesia.erl
index 9a630f18eb..fb29007780 100644
--- a/lib/mnesia/src/mnesia.erl
+++ b/lib/mnesia/src/mnesia.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 1996-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 1996-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 
@@ -2200,6 +2200,7 @@ system_info2(transaction_log_writes) -> mnesia_dumper:get_log_writes();
 system_info2(core_dir) ->  mnesia_monitor:get_env(core_dir); 
 system_info2(no_table_loaders) ->  mnesia_monitor:get_env(no_table_loaders); 
 system_info2(dc_dump_limit) ->  mnesia_monitor:get_env(dc_dump_limit); 
+system_info2(send_compressed) -> mnesia_monitor:get_env(send_compressed);
 
 system_info2(Item) -> exit({badarg, Item}).
 
@@ -2244,6 +2245,7 @@ system_info_items(yes) ->
      core_dir,
      no_table_loaders,
      dc_dump_limit,
+     send_compressed,
      version
     ];
 system_info_items(no) ->
diff --git a/lib/mnesia/src/mnesia_loader.erl b/lib/mnesia/src/mnesia_loader.erl
index 77c317abc5..3de329503e 100644
--- a/lib/mnesia/src/mnesia_loader.erl
+++ b/lib/mnesia/src/mnesia_loader.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 1998-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 1998-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 
@@ -438,6 +438,9 @@ make_table_fun(Pid, TabRec) ->
 
 get_data(Pid, TabRec) ->
     receive 
+	{Pid, {more_z, CompressedRecs}} when is_binary(CompressedRecs) ->
+	    Pid ! {TabRec, more},
+	    {zlib_uncompress(CompressedRecs), make_table_fun(Pid,TabRec)};
 	{Pid, {more, Recs}} ->
 	    Pid ! {TabRec, more},
 	    {Recs, make_table_fun(Pid,TabRec)};
@@ -769,6 +772,27 @@ dets_bchunk(Tab, Chunk) -> %% Arrg
 	Else -> Else
     end.	    
 
+zlib_compress(Data, Level) ->
+    BinData = term_to_binary(Data),
+    Z = zlib:open(),
+    zlib:deflateInit(Z, Level),
+    Bs = zlib:deflate(Z, BinData, finish),
+    zlib:deflateEnd(Z),
+    zlib:close(Z),
+    list_to_binary(Bs).
+
+zlib_uncompress(Data) when is_binary(Data) ->
+    binary_to_term(zlib:uncompress(Data)).
+
+compression_level() ->
+    NoCompression = 0,
+    case ?catch_val(send_compressed) of
+	{'EXIT', _} ->
+	    mnesia_lib:set(send_compressed, NoCompression),
+	    NoCompression;
+	Val -> Val
+    end.
+
 send_packet(N, Pid, _Chunk, '$end_of_table', OldNode) ->
     case OldNode of
 	true -> ignore; %% Old nodes can't handle the new no_more
@@ -779,8 +803,15 @@ send_packet(N, Pid, Chunk, {[], Cont}, OldNode) ->
     send_packet(N, Pid, Chunk, Chunk(Cont), OldNode);
 send_packet(N, Pid, Chunk, {Recs, Cont}, OldNode) when N < ?MAX_NOPACKETS ->
     case OldNode of
-	true -> Pid ! {self(), {more, [Recs]}}; %% Old need's wrapping list
-	false -> Pid ! {self(), {more, Recs}}
+        true ->
+            Pid ! {self(), {more, [Recs]}}; %% Old need's wrapping list
+        false ->
+            case compression_level() of
+                0 ->
+                    Pid ! {self(), {more, Recs}};
+                Level ->
+                    Pid ! {self(), {more_z, zlib_compress(Recs, Level)}}
+            end
     end,
     send_packet(N+1, Pid, Chunk, Chunk(Cont), OldNode);
 send_packet(_N, _Pid, _Chunk, DataState, _OldNode) ->
diff --git a/lib/mnesia/src/mnesia_monitor.erl b/lib/mnesia/src/mnesia_monitor.erl
index 05ae943e3b..ab1500d439 100644
--- a/lib/mnesia/src/mnesia_monitor.erl
+++ b/lib/mnesia/src/mnesia_monitor.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 1996-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 1996-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 
@@ -674,7 +674,8 @@ env() ->
      core_dir,
      pid_sort_order,
      no_table_loaders,
-     dc_dump_limit
+     dc_dump_limit,
+     send_compressed
     ].
 
 default_env(access_module) -> 
@@ -717,7 +718,9 @@ default_env(pid_sort_order) ->
 default_env(no_table_loaders) ->
     2;
 default_env(dc_dump_limit) ->
-    4.
+    4;
+default_env(send_compressed) ->
+    0.
 
 check_type(Env, Val) ->
     case catch do_check_type(Env, Val) of
@@ -763,7 +766,8 @@ do_check_type(pid_sort_order, standard) -> standard;
 do_check_type(pid_sort_order, "standard") -> standard;
 do_check_type(pid_sort_order, _) -> false;
 do_check_type(no_table_loaders, N) when is_integer(N), N > 0 -> N;
-do_check_type(dc_dump_limit,N) when is_number(N), N > 0 -> N.
+do_check_type(dc_dump_limit,N) when is_number(N), N > 0 -> N;
+do_check_type(send_compressed, L) when is_integer(L), L >= 0, L =< 9 -> L.
 
 bool(true) -> true;
 bool(false) -> false.