make sure that verbose mode is only applied once

lib/sqlite3.js

@@ -48,22 +48,28 @@ Database.prototype.each = function(sql) {
     return this;
 }
 
+var isVerbose = false;
+
 // Save the stack trace over EIO callbacks.
 sqlite3.verbose = function() {
-    var trace = require('./trace');
-    trace.extendTrace(Database.prototype, 'prepare');
-    trace.extendTrace(Database.prototype, 'get');
-    trace.extendTrace(Database.prototype, 'run');
-    trace.extendTrace(Database.prototype, 'all');
-    trace.extendTrace(Database.prototype, 'each');
-    trace.extendTrace(Database.prototype, 'exec');
-    trace.extendTrace(Database.prototype, 'close');
-    trace.extendTrace(Statement.prototype, 'bind');
-    trace.extendTrace(Statement.prototype, 'get');
-    trace.extendTrace(Statement.prototype, 'run');
-    trace.extendTrace(Statement.prototype, 'all');
-    trace.extendTrace(Statement.prototype, 'each');
-    trace.extendTrace(Statement.prototype, 'reset');
-    trace.extendTrace(Statement.prototype, 'finalize');
+    if (!isVerbose) {
+        var trace = require('./trace');
+        trace.extendTrace(Database.prototype, 'prepare');
+        trace.extendTrace(Database.prototype, 'get');
+        trace.extendTrace(Database.prototype, 'run');
+        trace.extendTrace(Database.prototype, 'all');
+        trace.extendTrace(Database.prototype, 'each');
+        trace.extendTrace(Database.prototype, 'exec');
+        trace.extendTrace(Database.prototype, 'close');
+        trace.extendTrace(Statement.prototype, 'bind');
+        trace.extendTrace(Statement.prototype, 'get');
+        trace.extendTrace(Statement.prototype, 'run');
+        trace.extendTrace(Statement.prototype, 'all');
+        trace.extendTrace(Statement.prototype, 'each');
+        trace.extendTrace(Statement.prototype, 'reset');
+        trace.extendTrace(Statement.prototype, 'finalize');
+        isVerbose = true;
+    }
+
     return this;
 };