Test and fix for infinite loops in view_servers, fix for crashed OS processes causing leaked erlang processes and fix for view server crashing when view group process terminates.

git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@780165 13f79535-47bb-0310-9956-ffa450edef68

9 files changed, 233 insertions, 172 deletions

diff --git a/share/www/script/test/view_errors.js b/share/www/script/test/view_errors.js
index 5d5223e8..c9ef6d0c 100644
--- a/share/www/script/test/view_errors.js
+++ b/share/www/script/test/view_errors.js
@@ -15,125 +15,149 @@ couchTests.view_errors = function(debug) {
   db.deleteDb();
   db.createDb();
   if (debug) debugger;
+  
+  
 
-  var doc = {integer: 1, string: "1", array: [1, 2, 3]};
-  T(db.save(doc).ok);
+  run_on_modified_server(
+    [{section: "couchdb",
+      key: "os_process_timeout",
+      value: "500"}],
+    function() {    
+      var doc = {integer: 1, string: "1", array: [1, 2, 3]};
+      T(db.save(doc).ok);
 
-  // emitting a key value that is undefined should result in that row not
-  // being included in the view results
-  var results = db.query(function(doc) {
-    emit(doc.undef, null);
-  });
-  T(results.total_rows == 0);
+      // emitting a key value that is undefined should result in that row not
+      // being included in the view results
+      var results = db.query(function(doc) {
+        emit(doc.undef, null);
+      });
+      T(results.total_rows == 0);
 
-  // if a view function throws an exception, its results are not included in
-  // the view index, but the view does not itself raise an error
-  var results = db.query(function(doc) {
-    doc.undef(); // throws an error
-  });
-  T(results.total_rows == 0);
+      // if a view function throws an exception, its results are not included in
+      // the view index, but the view does not itself raise an error
+      var results = db.query(function(doc) {
+        doc.undef(); // throws an error
+      });
+      T(results.total_rows == 0);
 
-  // if a view function includes an undefined value in the emitted key or
-  // value, an error is logged and the result is not included in the view
-  // index, and the view itself does not raise an error
-  var results = db.query(function(doc) {
-    emit([doc._id, doc.undef], null);
-  });
-  T(results.total_rows == 0);
+      // if a view function includes an undefined value in the emitted key or
+      // value, an error is logged and the result is not included in the view
+      // index, and the view itself does not raise an error
+      var results = db.query(function(doc) {
+        emit([doc._id, doc.undef], null);
+      });
+      T(results.total_rows == 0);
   
-  // querying a view with invalid params should give a resonable error message
-  var xhr = CouchDB.request("POST", "/test_suite_db/_temp_view?startkey=foo", {
-    headers: {"Content-Type": "application/json"},
-    body: JSON.stringify({language: "javascript", 
-      map : "function(doc){emit(doc.integer)}"
-    })
-  });
-  T(JSON.parse(xhr.responseText).error == "invalid_json");
+      // querying a view with invalid params should give a resonable error message
+      var xhr = CouchDB.request("POST", "/test_suite_db/_temp_view?startkey=foo", {
+        headers: {"Content-Type": "application/json"},
+        body: JSON.stringify({language: "javascript", 
+          map : "function(doc){emit(doc.integer)}"
+        })
+      });
+      T(JSON.parse(xhr.responseText).error == "invalid_json");
   
-  // views should ignore Content-Type, like the rest of CouchDB
-  var xhr = CouchDB.request("POST", "/test_suite_db/_temp_view", {
-    headers: {"Content-Type": "application/x-www-form-urlencoded"},
-    body: JSON.stringify({language: "javascript", 
-      map : "function(doc){}"
-    })
-  });
-  T(xhr.status == 200);
+      // views should ignore Content-Type, like the rest of CouchDB
+      var xhr = CouchDB.request("POST", "/test_suite_db/_temp_view", {
+        headers: {"Content-Type": "application/x-www-form-urlencoded"},
+        body: JSON.stringify({language: "javascript", 
+          map : "function(doc){}"
+        })
+      });
+      T(xhr.status == 200);
   
-  var map = function (doc) {emit(doc.integer, doc.integer);};
+      var map = function (doc) {emit(doc.integer, doc.integer);};
   
-  try {
-      db.query(map, null, {group: true});
-      T(0 == 1);
-  } catch(e) {
-      T(e.error == "query_parse_error");
-  }
+      try {
+          db.query(map, null, {group: true});
+          T(0 == 1);
+      } catch(e) {
+          T(e.error == "query_parse_error");
+      }
   
-  // reduce=false on map views doesn't work, so group=true will
-  // never throw for temp reduce views.
+      // reduce=false on map views doesn't work, so group=true will
+      // never throw for temp reduce views.
   
-  var designDoc = {
-    _id:"_design/test",
-    language: "javascript",
-    views: {
-      "no_reduce": {map:"function(doc) {emit(doc._id, null);}"},
-      "with_reduce": {
-        map:"function (doc) {emit(doc.integer, doc.integer)};",
-        reduce:"function (keys, values) { return sum(values); };"}
-    }
-  };
-  T(db.save(designDoc).ok);
+      var designDoc = {
+        _id:"_design/test",
+        language: "javascript",
+        views: {
+          "no_reduce": {map:"function(doc) {emit(doc._id, null);}"},
+          "with_reduce": {
+            map:"function (doc) {emit(doc.integer, doc.integer)};",
+            reduce:"function (keys, values) { return sum(values); };"}
+        }
+      };
+      T(db.save(designDoc).ok);
   
-  var designDoc2 = {
-    _id:"_design/testbig",
-    language: "javascript",
-    views: {
-      "reduce_too_big"  : {
-        map:"function (doc) {emit(doc.integer, doc.integer)};",
-        reduce:"function (keys, values) { var chars = []; for (var i=0; i < 1000; i++) {chars.push('wazzap');};return chars; };"}
-    }
-  };
-  T(db.save(designDoc2).ok);
+      var designDoc2 = {
+        _id:"_design/testbig",
+        language: "javascript",
+        views: {
+          "reduce_too_big"  : {
+            map:"function (doc) {emit(doc.integer, doc.integer)};",
+            reduce:"function (keys, values) { var chars = []; for (var i=0; i < 1000; i++) {chars.push('wazzap');};return chars; };"}
+        }
+      };
+      T(db.save(designDoc2).ok);
   
-  try {
-      db.view("test/no_reduce", {group: true});
-      T(0 == 1);
-  } catch(e) {
-      T(e.error == "query_parse_error");
-  }
+      try {
+          db.view("test/no_reduce", {group: true});
+          T(0 == 1);
+      } catch(e) {
+          T(e.error == "query_parse_error");
+      }
+  
+      try {
+        db.view("test/no_reduce", {reduce: true});
+        T(0 == 1);
+      } catch(e) {
+        T(db.last_req.status == 400);
+        T(e.error == "query_parse_error");
+      }
+
+      try {
+          db.view("test/with_reduce", {group: true, reduce: false});
+          T(0 == 1);
+      } catch(e) {
+          T(e.error == "query_parse_error");
+      }
   
-  try {
-    db.view("test/no_reduce", {reduce: true});
-    T(0 == 1);
-  } catch(e) {
-    T(db.last_req.status == 400);
-    T(e.error == "query_parse_error");
-  }
+      var designDoc3 = {
+        _id:"_design/infinite",
+        language: "javascript",
+        views: {
+          "infinite_loop" :{map:"function(doc) {while(true){emit(doc,doc);}};"}
+        }
+      };
+      T(db.save(designDoc3).ok);
 
-  try {
-      db.view("test/with_reduce", {group: true, reduce: false});
-      T(0 == 1);
-  } catch(e) {
-      T(e.error == "query_parse_error");
-  }
+      try {
+          db.view("infinite/infinite_loop");
+          T(0 == 1);
+      } catch(e) {
+          T(e.error == "os_process_error");
+      }
     
-  // Check error responses for invalid multi-get bodies.
-  var path = "/test_suite_db/_design/test/_view/no_reduce";
-  var xhr = CouchDB.request("POST", path, {body: "[]"});
-  T(xhr.status == 400);
-  result = JSON.parse(xhr.responseText);
-  T(result.error == "bad_request");
-  T(result.reason == "Request body must be a JSON object");
-  var data = "{\"keys\": 1}";
-  xhr = CouchDB.request("POST", path, {body:data});
-  T(xhr.status == 400);
-  result = JSON.parse(xhr.responseText);
-  T(result.error == "bad_request");
-  T(result.reason == "`keys` member must be a array.");
+      // Check error responses for invalid multi-get bodies.
+      var path = "/test_suite_db/_design/test/_view/no_reduce";
+      var xhr = CouchDB.request("POST", path, {body: "[]"});
+      T(xhr.status == 400);
+      result = JSON.parse(xhr.responseText);
+      T(result.error == "bad_request");
+      T(result.reason == "Request body must be a JSON object");
+      var data = "{\"keys\": 1}";
+      xhr = CouchDB.request("POST", path, {body:data});
+      T(xhr.status == 400);
+      result = JSON.parse(xhr.responseText);
+      T(result.error == "bad_request");
+      T(result.reason == "`keys` member must be a array.");
 
-  // if the reduce grows to fast, throw an overflow error
-  var path = "/test_suite_db/_design/testbig/_view/reduce_too_big";
-  xhr = CouchDB.request("GET", path);
-  T(xhr.status == 500);
-  result = JSON.parse(xhr.responseText);
-  T(result.error == "reduce_overflow_error");
+      // if the reduce grows to fast, throw an overflow error
+      var path = "/test_suite_db/_design/testbig/_view/reduce_too_big";
+      xhr = CouchDB.request("GET", path);
+      T(xhr.status == 500);
+      result = JSON.parse(xhr.responseText);
+      T(result.error == "reduce_overflow_error");
+    });
 };
diff --git a/src/couchdb/Makefile.am b/src/couchdb/Makefile.am
index 7105300b..e19a7539 100644
--- a/src/couchdb/Makefile.am
+++ b/src/couchdb/Makefile.am
@@ -13,9 +13,11 @@
 ICU_LOCAL_FLAGS = $(ICU_LOCAL_CFLAGS) $(ICU_LOCAL_LDFLAGS)
 
 # devdocdir = $(localdocdir)/developer/couchdb
-couchprivlibdir = $(localerlanglibdir)/couch-$(version)/priv/lib
-couchincludedir = $(localerlanglibdir)/couch-$(version)/include
-couchebindir = $(localerlanglibdir)/couch-$(version)/ebin
+couchlibdir = $(localerlanglibdir)/couch-$(version)
+couchprivdir = $(couchlibdir)/priv
+couchprivlibdir = $(couchlibdir)/priv/lib
+couchincludedir = $(couchlibdir)/include
+couchebindir = $(couchlibdir)/ebin
 
 couchprivlib_LTLIBRARIES = couch_erl_driver.la
 couch_erl_driver_la_SOURCES = couch_erl_driver.c
@@ -33,6 +35,8 @@ couchinclude_DATA = couch_db.hrl
 
 couchebin_DATA = $(compiled_files)
 
+couchpriv_SCRIPTS = priv/couchspawnkillable
+
 # dist_devdoc_DATA = $(doc_base) $(doc_modules)
 
 CLEANFILES = $(compiled_files) $(doc_base)
diff --git a/src/couchdb/couch.app.tpl.in b/src/couchdb/couch.app.tpl.in
index e0100cb4..259bac6c 100644
--- a/src/couchdb/couch.app.tpl.in
+++ b/src/couchdb/couch.app.tpl.in
@@ -1,4 +1,4 @@
-{application,couch,
+{application,couchdb,
              [{description,"@package_name@"},
               {vsn,"@version@"},
               {modules,[couch_btree,
diff --git a/src/couchdb/couch_os_process.erl b/src/couchdb/couch_os_process.erl
index 9a1fcb0c..75937eb8 100644
--- a/src/couchdb/couch_os_process.erl
+++ b/src/couchdb/couch_os_process.erl
@@ -14,7 +14,7 @@
 -behaviour(gen_server).
 
 -export([start_link/1, start_link/2, start_link/3, stop/1]).
--export([set_timeout/2, write/2, read/1, prompt/2, async/3]).
+-export([set_timeout/2, prompt/2]).
 -export([writeline/2, readline/1, writejson/2, readjson/1]).
 -export([init/1, terminate/2, handle_call/3, handle_cast/2, handle_info/2, code_change/3]).
 
@@ -27,7 +27,7 @@
      port,
      writer,
      reader,
-     timeout
+     timeout=5000
     }).
 
 start_link(Command) ->
@@ -44,24 +44,15 @@ stop(Pid) ->
 set_timeout(Pid, TimeOut) when is_integer(TimeOut) ->
     ok = gen_server:call(Pid, {set_timeout, TimeOut}).
 
-write(Pid, Data) ->
-    gen_server:call(Pid, {write, Data}).
-
-read(Pid) ->
-    gen_server:call(Pid, read).
-
 prompt(Pid, Data) ->
     case gen_server:call(Pid, {prompt, Data}, infinity) of
         {ok, Result} ->
             Result;
-        {error, Error} ->
+        Error ->
             ?LOG_DEBUG("OS Process Error ~p",[Error]),
             throw(Error)
     end.
 
-async(Pid, Data, CallBack) ->
-    gen_server:cast(Pid, {async, Data, CallBack}).
-
 % Utility functions for reading and writing
 % in custom functions
 writeline(OsProc, Data) when is_record(OsProc, os_proc) ->
@@ -103,17 +94,31 @@ readjson(OsProc) when is_record(OsProc, os_proc) ->
         Result
     end.
 
+
 % gen_server API
 init([Command, Options, PortOptions]) ->
-    BaseTimeOut = list_to_integer(couch_config:get(
-        "couchdb", "os_process_timeout", "5000")),
+    case code:priv_dir(couch) of
+    {error, bad_name} ->
+        % small hack, in dev mode "app" is couchdb. Fixing requires renaming
+        % src/couch to src/couch. Not really worth the hassle.-Damien
+        PrivDir = code:priv_dir(couchdb);
+    PrivDir -> ok
+    end,
+    Spawnkiller = filename:join(PrivDir, "couchspawnkillable"),
     BaseProc = #os_proc{
         command=Command,
-        port=open_port({spawn, Command}, PortOptions),
+        port=open_port({spawn, Spawnkiller ++ " " ++ Command}, PortOptions),
         writer=fun writejson/2,
-        reader=fun readjson/1,
-        timeout=BaseTimeOut
+        reader=fun readjson/1
     },
+    KillCmd = readline(BaseProc),
+    Pid = self(),
+    spawn(fun() ->
+            % this ensure the real os process is killed when this process dies.
+            erlang:monitor(process, Pid),
+            receive _ -> ok end,
+            os:cmd(?b2l(KillCmd))
+        end),
     OsProc =
     lists:foldl(fun(Opt, Proc) ->
         case Opt of
@@ -127,36 +132,22 @@ init([Command, Options, PortOptions]) ->
     end, BaseProc, Options),
     {ok, OsProc}.
 
-terminate(_Reason, #os_proc{port=nil}) ->
-    ok;
 terminate(_Reason, #os_proc{port=Port}) ->
     catch port_close(Port),
     ok.
 
 handle_call({set_timeout, TimeOut}, _From, OsProc) ->
     {reply, ok, OsProc#os_proc{timeout=TimeOut}};
-handle_call({write, Data}, _From, OsProc) ->
-    Writer = OsProc#os_proc.writer,
-    {reply, Writer(OsProc, Data), OsProc};
-handle_call(read, _From, OsProc) ->
-    Reader = OsProc#os_proc.reader,
-    {reply, Reader(OsProc), OsProc};
 handle_call({prompt, Data}, _From, OsProc) ->
     #os_proc{writer=Writer, reader=Reader} = OsProc,
-    Writer(OsProc, Data),
-    Result = try Reader(OsProc) of
-        Ok -> {ok, Ok}
+    try
+        Writer(OsProc, Data),
+        {reply, {ok, Reader(OsProc)}, OsProc}
     catch
         throw:OsError ->
-            {error, OsError}
-    end,
-    {reply, Result, OsProc}.
+            {stop, normal, OsError, OsProc}
+    end.
 
-handle_cast({async, Data, CallBack}, OsProc) ->
-    #os_proc{writer=Writer, reader=Reader} = OsProc,
-    Writer(OsProc, Data),
-    CallBack(Reader(OsProc)),
-    {noreply, OsProc};
 handle_cast(stop, OsProc) ->
     {stop, normal, OsProc};
 handle_cast(Msg, OsProc) ->
diff --git a/src/couchdb/couch_query_servers.erl b/src/couchdb/couch_query_servers.erl
index 7c82abe7..ef2bde3b 100644
--- a/src/couchdb/couch_query_servers.erl
+++ b/src/couchdb/couch_query_servers.erl
@@ -118,7 +118,7 @@ recombine_reduce_results([<<"_", _/binary>>|RedSrcs], OsResults, [BRes|BuiltinRe
 recombine_reduce_results([_OsFun|RedSrcs], [OsR|OsResults], BuiltinResults, Acc) ->
     recombine_reduce_results(RedSrcs, OsResults, BuiltinResults, [OsR|Acc]).
 
-os_reduce(Lang, [], KVs) ->
+os_reduce(_Lang, [], _KVs) ->
     {ok, []};
 os_reduce(Lang, OsRedSrcs, KVs) ->
     Pid = get_os_process(Lang),
@@ -130,7 +130,7 @@ os_reduce(Lang, OsRedSrcs, KVs) ->
     end,
     {ok, OsResults}.
 
-builtin_reduce(_Re, [], KVs, Acc) ->
+builtin_reduce(_Re, [], _KVs, Acc) ->
     {ok, lists:reverse(Acc)};
 builtin_reduce(Re, [<<"_sum">>|BuiltinReds], KVs, Acc) ->
     Sum = builtin_sum_rows(KVs),
@@ -242,6 +242,7 @@ init([]) ->
     lists:foreach(fun({Lang, Command}) ->
         true = ets:insert(Langs, {?l2b(Lang), Command})
     end, couch_config:get("query_servers")),
+    process_flag(trap_exit, true),
     {ok, {Langs, PidLangs, Pids, InUse}}.
 
 terminate(_Reason, _Server) ->
@@ -255,13 +256,15 @@ handle_call({get_proc, Lang}, _From, {Langs, PidLangs, Pids, InUse}=Server) ->
         add_value(PidLangs, Pid, Lang),
         rem_from_list(Pids, Lang, Pid),
         add_to_list(InUse, Lang, Pid),
-        QueryConfig = get_query_server_config(),
-        true = couch_os_process:prompt(Pid, [<<"reset">>, QueryConfig]),
-        {reply, Pid, Server};
+        {reply, {recycled, Pid, get_query_server_config()}, Server};
     _ ->
-        {ok, Pid} = new_process(Langs, Lang),
-        add_to_list(InUse, Lang, Pid),
-        {reply, Pid, Server}
+        case (catch new_process(Langs, Lang)) of
+        {ok, Pid} ->
+            add_to_list(InUse, Lang, Pid),
+            {reply, {new, Pid}, Server};
+        Error ->
+            {reply, Error, Server}
+        end
     end;
 handle_call({ret_proc, Lang, Pid}, _From, {_, _, Pids, InUse}=Server) ->
     % Along with max process limit, here we should check
@@ -273,22 +276,20 @@ handle_call({ret_proc, Lang, Pid}, _From, {_, _, Pids, InUse}=Server) ->
 handle_cast(_Whatever, Server) ->
     {noreply, Server}.
 
-handle_info({'EXIT', Pid, Status}, {Langs, PidLangs, Pids, InUse}) ->
+handle_info({'EXIT', Pid, Status}, {_, PidLangs, Pids, InUse}=Server) ->
     case ets:lookup(PidLangs, Pid) of
     [{Pid, Lang}] ->
         case Status of
         normal -> ok;
         _ -> ?LOG_DEBUG("Linked process died abnormally: ~p (reason: ~p)", [Pid, Status])
         end,
-        {ok, {
-            Langs,
-            rem_value(PidLangs, Pid),
-            rem_from_list(Pids, Lang, Pid),
-            rem_from_list(InUse, Lang, Pid)
-        }};
+        rem_value(PidLangs, Pid),
+        catch rem_from_list(Pids, Lang, Pid),
+        catch rem_from_list(InUse, Lang, Pid),
+        {noreply, Server};
     [] ->
         ?LOG_DEBUG("Unknown linked process died: ~p (reason: ~p)", [Pid, Status]),
-        {ok, {Langs, PidLangs, Pids, InUse}}
+        {stop, Status, Server}
     end.
 
 code_change(_OldVsn, State, _Extra) ->
@@ -302,27 +303,45 @@ get_query_server_config() ->
     {[{<<"reduce_limit">>, ReduceLimit}]}.
 
 new_process(Langs, Lang) ->
-    Proc =
     case ets:lookup(Langs, Lang) of
     [{Lang, Command}] ->
         couch_os_process:start_link(Command);
     _ ->
-        throw({unknown_query_language, Lang})
-    end,
-    Proc.
+        {unknown_query_language, Lang}
+    end.
 
 get_os_process(Lang) ->
-    gen_server:call(couch_query_servers, {get_proc, Lang}).
+    case gen_server:call(couch_query_servers, {get_proc, Lang}) of
+    {new, Pid} ->
+        couch_os_process:set_timeout(Pid, list_to_integer(couch_config:get(
+                "couchdb", "os_process_timeout", "5000"))),
+        link(Pid),
+        Pid;
+    {recycled, Pid, QueryConfig} ->
+        case (catch couch_os_process:prompt(Pid, [<<"reset">>, QueryConfig])) of
+        true ->
+            couch_os_process:set_timeout(Pid, list_to_integer(couch_config:get(
+                "couchdb", "os_process_timeout", "5000"))),
+            link(Pid),
+            Pid;
+        _ ->
+            catch couch_os_process:stop(Pid),
+            get_os_process(Lang)
+        end;
+    Error ->
+        throw(Error)
+    end.
 
 ret_os_process(Lang, Pid) ->
     true = gen_server:call(couch_query_servers, {ret_proc, Lang, Pid}),
+    catch unlink(Pid),
     ok.
 
 add_value(Tid, Key, Value) ->
     true = ets:insert(Tid, {Key, Value}).
 
 rem_value(Tid, Key) ->
-    true = ets:insert(Tid, Key).
+    true = ets:delete(Tid, Key).
 
 add_to_list(Tid, Key, Value) ->
     case ets:lookup(Tid, Key) of
diff --git a/src/couchdb/couch_server_sup.erl b/src/couchdb/couch_server_sup.erl
index 344073a3..e59286f3 100644
--- a/src/couchdb/couch_server_sup.erl
+++ b/src/couchdb/couch_server_sup.erl
@@ -32,8 +32,10 @@ start_link(IniFiles) ->
     end.
 
 restart_core_server() ->
+    supervisor:terminate_child(couch_secondary_services, couch_server),
     supervisor:terminate_child(couch_primary_services, couch_server),
-    supervisor:restart_child(couch_primary_services, couch_server).
+    supervisor:restart_child(couch_primary_services, couch_server),
+    supervisor:restart_child(couch_secondary_services, couch_server).
 
 couch_config_start_link_wrapper(IniFiles, FirstConfigPid) ->
     case is_process_alive(FirstConfigPid) of
diff --git a/src/couchdb/couch_view.erl b/src/couchdb/couch_view.erl
index b74fb47d..301ea8b7 100644
--- a/src/couchdb/couch_view.erl
+++ b/src/couchdb/couch_view.erl
@@ -260,7 +260,7 @@ handle_call({start_group_server, DbName, GroupId}, _From, #server{root_dir=Root}
     case ets:lookup(group_servers_by_name, {DbName, GroupId}) of
     [] ->
         ?LOG_DEBUG("Spawning new group server for view group ~s in database ~s.", [GroupId, DbName]),
-        case couch_view_group:start_link({view, Root, DbName, GroupId}) of
+        case (catch couch_view_group:start_link({view, Root, DbName, GroupId})) of
         {ok, NewPid} ->
             add_to_ets(NewPid, DbName, GroupId),
             {reply, {ok, NewPid}, Server};
diff --git a/src/couchdb/couch_view_group.erl b/src/couchdb/couch_view_group.erl
index 28679927..0ab1077e 100644
--- a/src/couchdb/couch_view_group.erl
+++ b/src/couchdb/couch_view_group.erl
@@ -274,9 +274,10 @@ handle_info({'DOWN',_,_,_,_}, State) ->
     {stop, normal, reply_all(State, shutdown)}.
 
 
-terminate(Reason, State) ->
-    reply_all(State, Reason),
-    couch_util:terminate_linked(Reason),
+terminate(Reason, #group_state{updater_pid=Update, compactor_pid=Compact}=S) ->
+    reply_all(S, Reason),
+    catch exit(Update, Reason),
+    catch exit(Compact, Reason),
     ok.
 
 code_change(_OldVsn, State, _Extra) ->
diff --git a/src/couchdb/priv/couchspawnkillable b/src/couchdb/priv/couchspawnkillable
new file mode 100644
index 00000000..3d85ea3c
--- /dev/null
+++ b/src/couchdb/priv/couchspawnkillable
@@ -0,0 +1,20 @@
+#! /bin/sh -e
+
+# 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.
+
+# The purpose of this script is to echo an OS specific command before launching
+# the actual process. This provides a way for Erlang to hard-kill its external
+# processes.
+
+echo "kill -9 $$"
+exec $*
\ No newline at end of file