Fixed #8901 -- Corrected the PostgreSQL sequence reset code when field identifiers exceed the maximum identifier length. Thanks to adam@zuerchertech.com for the report, and Matt Hoskins for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13328 bcc190cf-cafb-0310-a4f2-bffc1f526a37

AUTHORS

@@ -220,6 +220,7 @@ answer newbie questions, and generally made Django that much better:
     Kieran Holland <http://www.kieranholland.com>
     Sung-Jin Hong <serialx.net@gmail.com>
     Leo "hylje" Honkanen <sealage@gmail.com>
+    Matt Hoskins <skaffenuk@googlemail.com>
     Tareque Hossain <http://www.codexn.com>
     Richard House <Richard.House@i-logue.com>
     Robert Rock Howard <http://djangomojo.com/>

django/db/backends/postgresql/creation.py

@@ -1,4 +1,5 @@
 from django.db.backends.creation import BaseDatabaseCreation
+from django.db.backends.util import truncate_name
 
 class DatabaseCreation(BaseDatabaseCreation):
     # This dictionary maps Field objects to their associated PostgreSQL column
@@ -51,7 +52,7 @@ class DatabaseCreation(BaseDatabaseCreation):
 
             def get_index_sql(index_name, opclass=''):
                 return (style.SQL_KEYWORD('CREATE INDEX') + ' ' +
-                        style.SQL_TABLE(qn(index_name)) + ' ' +
+                        style.SQL_TABLE(qn(truncate_name(index_name,self.connection.ops.max_name_length()))) + ' ' +
                         style.SQL_KEYWORD('ON') + ' ' +
                         style.SQL_TABLE(qn(db_table)) + ' ' +
                         "(%s%s)" % (style.SQL_FIELD(qn(f.column)), opclass) +

django/db/backends/postgresql/operations.py

@@ -54,7 +54,9 @@ class DatabaseOperations(BaseDatabaseOperations):
         return '%s'
 
     def last_insert_id(self, cursor, table_name, pk_name):
-        cursor.execute("SELECT CURRVAL('\"%s_%s_seq\"')" % (table_name, pk_name))
+        # Use pg_get_serial_sequence to get the underlying sequence name
+        # from the table name and column name (available since PostgreSQL 8)
+        cursor.execute("SELECT CURRVAL(pg_get_serial_sequence('%s','%s'))" % (table_name, pk_name))
         return cursor.fetchone()[0]
 
     def no_limit_value(self):
@@ -90,13 +92,14 @@ class DatabaseOperations(BaseDatabaseOperations):
             for sequence_info in sequences:
                 table_name = sequence_info['table']
                 column_name = sequence_info['column']
-                if column_name and len(column_name) > 0:
+                if not (column_name and len(column_name) > 0):
-                    sequence_name = '%s_%s_seq' % (table_name, column_name)
+                    # This will be the case if it's an m2m using an autogenerated
-                else:
+                    # intermediate table (see BaseDatabaseIntrospection.sequence_list)
-                    sequence_name = '%s_id_seq' % table_name
+                    column_name = 'id'
-                sql.append("%s setval('%s', 1, false);" % \
+                sql.append("%s setval(pg_get_serial_sequence('%s','%s'), 1, false);" % \
                     (style.SQL_KEYWORD('SELECT'),
-                    style.SQL_FIELD(self.quote_name(sequence_name)))
+                    style.SQL_TABLE(table_name),
+                    style.SQL_FIELD(column_name))
                 )
             return sql
         else:
@@ -110,11 +113,15 @@ class DatabaseOperations(BaseDatabaseOperations):
             # Use `coalesce` to set the sequence for each model to the max pk value if there are records,
             # or 1 if there are none. Set the `is_called` property (the third argument to `setval`) to true
             # if there are records (as the max pk value is already in use), otherwise set it to false.
+            # Use pg_get_serial_sequence to get the underlying sequence name from the table name
+            # and column name (available since PostgreSQL 8)
+
             for f in model._meta.local_fields:
                 if isinstance(f, models.AutoField):
-                    output.append("%s setval('%s', coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
+                    output.append("%s setval(pg_get_serial_sequence('%s','%s'), coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
                         (style.SQL_KEYWORD('SELECT'),
-                        style.SQL_FIELD(qn('%s_%s_seq' % (model._meta.db_table, f.column))),
+                        style.SQL_TABLE(model._meta.db_table),
+                        style.SQL_FIELD(f.column),
                         style.SQL_FIELD(qn(f.column)),
                         style.SQL_FIELD(qn(f.column)),
                         style.SQL_KEYWORD('IS NOT'),
@@ -123,9 +130,10 @@ class DatabaseOperations(BaseDatabaseOperations):
                     break # Only one AutoField is allowed per model, so don't bother continuing.
             for f in model._meta.many_to_many:
                 if not f.rel.through:
-                    output.append("%s setval('%s', coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
+                    output.append("%s setval(pg_get_serial_sequence('%s','%s'), coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
                         (style.SQL_KEYWORD('SELECT'),
-                        style.SQL_FIELD(qn('%s_id_seq' % f.m2m_db_table())),
+                        style.SQL_TABLE(model._meta.db_table),
+                        style.SQL_FIELD('id'),
                         style.SQL_FIELD(qn('id')),
                         style.SQL_FIELD(qn('id')),
                         style.SQL_KEYWORD('IS NOT'),

tests/regressiontests/backends/models.py

@@ -1,5 +1,7 @@
+from django.conf import settings
 from django.db import models
-from django.db import connection
+from django.db import connection, DEFAULT_DB_ALIAS
+
 
 class Square(models.Model):
     root = models.IntegerField()
@@ -8,6 +10,7 @@ class Square(models.Model):
     def __unicode__(self):
         return "%s ** 2 == %s" % (self.root, self.square)
 
+
 class Person(models.Model):
     first_name = models.CharField(max_length=20)
     last_name = models.CharField(max_length=20)
@@ -15,11 +18,25 @@ class Person(models.Model):
     def __unicode__(self):
         return u'%s %s' % (self.first_name, self.last_name)
 
+
 class SchoolClass(models.Model):
     year = models.PositiveIntegerField()
     day = models.CharField(max_length=9, blank=True)
     last_updated = models.DateTimeField()
 
+# Unfortunately, the following model breaks MySQL hard.
+# Until #13711 is fixed, this test can't be run under MySQL.
+if settings.DATABASES[DEFAULT_DB_ALIAS]['ENGINE'] != 'django.db.backends.mysql':
+    class VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ(models.Model):
+        class Meta:
+            # We need to use a short actual table name or
+            # we hit issue #8548 which we're not testing!
+            verbose_name = 'model_with_long_table_name'
+        primary_key_is_quite_long_zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz = models.AutoField(primary_key=True)
+        charfield_is_quite_long_zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz = models.CharField(max_length=100)
+        m2m_also_quite_long_zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz = models.ManyToManyField(Person,blank=True)
+
+
 qn = connection.ops.quote_name
 
 __test__ = {'API_TESTS': """

tests/regressiontests/backends/tests.py

@@ -1,13 +1,17 @@
 # -*- coding: utf-8 -*-
 # Unit and doctests for specific database backends.
 import datetime
-import models
 import unittest
+
+from django.conf import settings
+from django.core import management
+from django.core.management.color import no_style
 from django.db import backend, connection, DEFAULT_DB_ALIAS
 from django.db.backends.signals import connection_created
-from django.conf import settings
 from django.test import TestCase
 
+from regressiontests.backends import models
+
 class Callproc(unittest.TestCase):
 
     def test_dbms_session(self):
@@ -76,6 +80,7 @@ class DateQuotingTest(TestCase):
         classes = models.SchoolClass.objects.filter(last_updated__day=20)
         self.assertEqual(len(classes), 1)
 
+
 class ParameterHandlingTest(TestCase):
     def test_bad_parameter_count(self):
         "An executemany call with too many/not enough parameters will raise an exception (Refs #12612)"
@@ -88,6 +93,50 @@ class ParameterHandlingTest(TestCase):
         self.assertRaises(Exception, cursor.executemany, query, [(1,2,3),])
         self.assertRaises(Exception, cursor.executemany, query, [(1,),])
 
+# Unfortunately, the following tests would be a good test to run on all
+# backends, but it breaks MySQL hard. Until #13711 is fixed, it can't be run
+# everywhere (although it would be an effective test of #13711).
+if settings.DATABASES[DEFAULT_DB_ALIAS]['ENGINE'] != 'django.db.backends.mysql':
+    class LongNameTest(TestCase):
+        """Long primary keys and model names can result in a sequence name
+        that exceeds the database limits, which will result in truncation
+        on certain databases (e.g., Postgres). The backend needs to use
+        the correct sequence name in last_insert_id and other places, so
+        check it is. Refs #8901.
+        """
+
+        def test_sequence_name_length_limits_create(self):
+            """Test creation of model with long name and long pk name doesn't error. Ref #8901"""
+            models.VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ.objects.create()
+
+        def test_sequence_name_length_limits_m2m(self):
+            """Test an m2m save of a model with a long name and a long m2m field name doesn't error as on Django >=1.2 this now uses object saves. Ref #8901"""
+            obj = models.VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ.objects.create()
+            rel_obj = models.Person.objects.create(first_name='Django', last_name='Reinhardt')
+            obj.m2m_also_quite_long_zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz.add(rel_obj)
+
+        def test_sequence_name_length_limits_flush(self):
+            """Test that sequence resetting as part of a flush with model with long name and long pk name doesn't error. Ref #8901"""
+            # A full flush is expensive to the full test, so we dig into the
+            # internals to generate the likely offending SQL and run it manually
+
+            # Some convenience aliases
+            VLM = models.VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
+            VLM_m2m = VLM.m2m_also_quite_long_zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz.through
+            tables = [
+                VLM._meta.db_table,
+                VLM_m2m._meta.db_table,
+            ]
+            sequences = [
+                {
+                    'column': VLM._meta.pk.column,
+                    'table': VLM._meta.db_table
+                },
+            ]
+            cursor = connection.cursor()
+            for statement in connection.ops.sql_flush(no_style(), tables, sequences):
+                cursor.execute(statement)
+
 
 def connection_created_test(sender, **kwargs):
     print 'connection_created signal'