tdb_sql: Up the number of frames in traceback.

tdb_sql has a lot of functions. Seven frames was frequently insufficient
to see who was phone.

r2/r2/lib/db/tdb_sql.py

@@ -369,7 +369,7 @@ def add_request_info(select):
     def sanitize(txt):
         return _spaces.sub(' ', txt).replace("/", "|").replace("-", "_").replace(';', "").replace("*", "").replace(r"/", "")
 
-    tb = simple_traceback()
+    tb = simple_traceback(limit=12)
     try:
         if (hasattr(request, 'path') and
             hasattr(request, 'ip') and

r2/r2/lib/lock.py

@@ -65,7 +65,7 @@ class MemcacheLock(object):
     def acquire(self):
         start = datetime.now()
 
-        my_info = (reddit_host, reddit_pid, simple_traceback())
+        my_info = (reddit_host, reddit_pid, simple_traceback(limit=7))
 
         #if this thread already has this lock, move on
         if self.key in self.locks:

r2/r2/lib/utils/utils.py

@@ -1401,10 +1401,14 @@ def parse_http_basic(authorization_header):
     return require_split(auth_data, 2, ":")
 
 
-def simple_traceback():
-    """Generate a pared-down traceback that's human readable but small."""
+def simple_traceback(limit):
+    """Generate a pared-down traceback that's human readable but small.
 
-    stack_trace = traceback.extract_stack(limit=7)[:-2]
+    `limit` is how many frames of the stack to put in the traceback.
+
+    """
+
+    stack_trace = traceback.extract_stack(limit=limit)[:-2]
     return "\n".join(":".join((os.path.basename(filename),
                                function_name,
                                str(line_number),