Documented a limit of the SQLite backend, in relation with the bulk_create function. Refs #17788.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17653 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 15 insertions, 0 deletions

diff --git a/docs/ref/models/querysets.txt b/docs/ref/models/querysets.txt
index 13504f41cf..2b24fdd05c 100644
--- a/docs/ref/models/querysets.txt
+++ b/docs/ref/models/querysets.txt
@@ -1371,6 +1371,21 @@ This has a number of caveats though:
 * If the model's primary key is an :class:`~django.db.models.AutoField` it
   does not retrieve and set the primary key attribute, as ``save()`` does.
 
+.. admonition:: Limits of SQLite
+
+    SQLite sets a limit on the number of parameters per SQL statement. The
+    maximum is defined by the SQLITE_MAX_VARIABLE_NUMBER_ compilation option,
+    which defaults to 999. For instance, if your model has 8 fields (including
+    the primary key), you cannot create more than 999 // 8 = 124 instances at
+    a time. If you exceed this limit, you will get an exception::
+
+        django.db.utils.DatabaseError: too many SQL variables
+
+    If your application's performance requirements exceed SQLite's limits, you
+    should switch to another database engine, such as PostgreSQL.
+
+.. _SQLITE_MAX_VARIABLE_NUMBER: http://sqlite.org/limits.html#max_variable_number
+
 count
 ~~~~~