MySQL Load: Combine sql and exit signal in one port command (#724)

Author: greg-rychlewski

lib/ecto/adapters/myxql.ex

@@ -588,16 +588,10 @@ defmodule Ecto.Adapters.MyXQL do
       args: args
     ]
 
-    # Trap exits in case mysql dies in the middle of execution so that we can surface the error
-    old_trap_exit = Process.flag(:trap_exit, true)
     port = Port.open({:spawn_executable, abs_cmd}, port_opts)
-    Port.command(port, contents)
-    # Use this as a signal to close the port since we cannot
-    # send an exit command to mysql in batch mode
-    Port.command(port, ";SELECT '__ECTO_EOF__';\n")
-    result = collect_output(port, "")
-    Process.flag(:trap_exit, old_trap_exit)
-    result
+    send(port, {self(), {:command, contents}})
+    send(port, {self(), {:command, ";SELECT '__ECTO_EOF__';\n"}})
+    collect_output(port, "")
   end
 
   defp args_env(opts, opt_args) do
@@ -657,9 +651,6 @@ defmodule Ecto.Adapters.MyXQL do
           collect_output(port, acc)
         end
 
-      {:EXIT, ^port, _reason} ->
-        {acc, 1}
-
       {^port, {:exit_status, status}} ->
         {acc, status}
     end