--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/book/en/annexes/rql/debugging.rst	Wed Jul 07 10:53:03 2010 +0200
@@ -0,0 +1,56 @@
+.. -*- coding: utf-8 -*-
+
+.. _DEBUGGING:
+
+Debugging RQL
+-------------
+
+Available levels
+~~~~~~~~~~~~~~~~
+
+:DBG_NONE:
+    no debug information (current mode)
+
+:DBG_RQL:
+    rql execution information
+
+:DBG_SQL:
+    executed sql
+
+:DBG_REPO:
+    repository events
+
+:DBG_MS:
+    multi-sources
+
+:DBG_MORE:
+    more verbosity
+
+:DBG_ALL:
+    all level enabled
+
+
+Enable verbose output
+~~~~~~~~~~~~~~~~~~~~~
+
+It may be interested to enable a verboser output to debug your RQL statements:
+
+.. sourcecode:: python
+
+    from cubicweb import server
+    server.set_debug(server.DBG_RQL|server.DBG_SQL|server.DBG_ALL)
+
+
+Detect largest RQL queries
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+See `Profiling and performance` chapter (see :ref:`PROFILING`).
+
+
+API
+~~~
+
+.. autofunction:: cubicweb.server.set_debug
+
+.. autoclass:: cubicweb.server.debugged
+