Add a more clear note about query builder caching (issue #2721)

1 files changed, 6 insertions, 1 deletions

diff --git a/user_guide_src/source/database/query_builder.rst b/user_guide_src/source/database/query_builder.rst
index 9a96db003..5bfdfdb52 100644
--- a/user_guide_src/source/database/query_builder.rst
+++ b/user_guide_src/source/database/query_builder.rst
@@ -1058,4 +1058,9 @@ run the query::
 	$data = $this->db->get()->result_array();
 
 	// Would execute and return an array of results of the following query:
-	// SELECT field1, field1 from mytable where field3 = 5;
\ No newline at end of file
+	// SELECT field1, field1 from mytable where field3 = 5;
+
+.. note:: Double calls to ``get_compiled_select()`` while you're using the
+	Query Builder Caching functionality and NOT resetting your queries
+	will results in the cache being merged twice. That in turn will
+	i.e. if you're caching a ``select()`` - select the same field twice.
\ No newline at end of file