add postgres create index concurrently support

README.md

@@ -118,9 +118,32 @@ It is up to you to ensure that the expressions are otherwise valid SQL and have
 Using [Django's query expressions](https://docs.djangoproject.com/en/1.11/ref/models/expressions/) that check the syntax and generate valid SQL
 for either database is planned for a future version.
 
+To use concurrent index creation in postgres, you should add index in a regular way,
+but after makemigration, change generated migration:
+ - atomic=False,
+ - add arg: concurrently=True
 
+```python
+class Migration(migrations.Migration):
+    atomic = False
+
+    operations = [
+        migrations.AddIndex(
+            model_name='dog',
+            index=partial_index.PartialIndex(
+                fields=[b'id'],
+                name='dog_id_c78984_partial', unique=True,
+                concurrently=True
+            ),
+        ),
+    ]
+
+```
 ## Version History
 
+### 0.4.1.dev
+add Postgres Create Index Concurrently support
+
 ### 0.4.0 (latest)
 * Add support for Django 2.0.
 

partial_index/__init__.py

@@ -26,14 +26,17 @@ class PartialIndex(Index):
     # The "partial" suffix is 4 letters longer than the default "idx".
     max_name_length = 34
     sql_create_index = {
-        'postgresql': 'CREATE%(unique)s INDEX %(name)s ON %(table)s%(using)s (%(columns)s)%(extra)s WHERE %(where)s',
+        'postgresql': 'CREATE%(unique)s INDEX%(concurrently)s %(name)s ON %(table)s%(using)s (%(columns)s)%(extra)s WHERE %(where)s;',
         'sqlite': 'CREATE%(unique)s INDEX %(name)s ON %(table)s%(using)s (%(columns)s) WHERE %(where)s',
     }
 
     # Mutable default fields=[] looks wrong, but it's copied from super class.
-    def __init__(self, fields=[], name=None, unique=None, where='', where_postgresql='', where_sqlite=''):
+    def __init__(self, fields=[], name=None, unique=None, where='', where_postgresql='',
+                 where_sqlite='', concurrently=False):
         if unique not in [True, False]:
             raise ValueError('Unique must be True or False')
+        if concurrently not in [True, False]:
+            raise ValueError('Unique must be True or False')
         if where:
             if where_postgresql or where_sqlite:
                 raise ValueError('If providing a single where predicate, must not provide where_postgresql or where_sqlite')
@@ -44,6 +47,7 @@ def __init__(self, fields=[], name=None, unique=None, where='', where_postgresql
                 raise ValueError('If providing a separate where_postgresql and where_sqlite, then they must be different.' +
                                  'If the same expression works for both, just use single where.')
         self.unique = unique
+        self.concurrently = concurrently
         self.where = where
         self.where_postgresql = where_postgresql
         self.where_sqlite = where_sqlite
@@ -99,6 +103,7 @@ def get_sql_create_template_values(self, model, schema_editor, using):
 
         # PartialIndex updates:
         parameters['unique'] = ' UNIQUE' if self.unique else ''
+        parameters['concurrently'] = ' CONCURRENTLY' if self.concurrently else ''
         # Note: the WHERE predicate is not yet checked for syntax or field names, and is inserted into the CREATE INDEX query unescaped.
         # This is bad for usability, but is not a security risk, as the string cannot come from user input.
         vendor = self.get_valid_vendor(schema_editor)

setup.py

@@ -6,7 +6,7 @@
 setup(
     name='django-partial-index',
     packages=['partial_index'],
-    version='0.4.0',
+    version='0.4.1.dev',
     description='PostgreSQL and SQLite partial indexes for Django models',
     long_description=open('README.md').read(),
     author='Mattias Linnap',