Skip migration 0141 if partitioned

Closes #3993

posthog/migrations/0141_events_created_at_index.py

@@ -1,7 +1,24 @@
 # Generated by Django 3.0.11 on 2021-03-26 12:10
 
 from django.contrib.postgres.operations import AddIndexConcurrently  # type: ignore
-from django.db import migrations, models
+from django.db import connection, migrations, models
+
+
+def migrate(apps, schema_editor):
+    with connection.cursor() as cursor:
+        cursor.execute(
+            """SELECT exists(SELECT FROM information_schema.tables where table_name = \'posthog_event_default\')"""
+        )
+        exists = cursor.fetchone()
+        if not exists[0]:
+            cursor.execute("CREATE INDEX CONCURRENTLY posthog_eve_created_6a34ca_idx ON posthog_event(created_at)")
+            return
+        else:
+            print("Skipping migration 0141 because of partitions!")
+
+
+def backwards(apps, schema_editor):
+    pass
 
 
 class Migration(migrations.Migration):
@@ -12,7 +29,5 @@ class Migration(migrations.Migration):
     ]
 
     operations = [
-        AddIndexConcurrently(
-            model_name="event", index=models.Index(fields=["created_at"], name="posthog_eve_created_6a34ca_idx"),
-        ),
+        migrations.RunPython(migrate, backwards),
     ]

posthog/migrations/0143_user_uuid.py

@@ -12,6 +12,10 @@ def create_user_uuid(apps, schema_editor):
         user.save()
 
 
+def backwards(app, schema_editor):
+    pass
+
+
 class Migration(migrations.Migration):
 
     dependencies = [
@@ -20,7 +24,7 @@ class Migration(migrations.Migration):
 
     operations = [
         migrations.AddField(model_name="user", name="uuid", field=models.UUIDField(blank=True, null=True),),
-        migrations.RunPython(create_user_uuid),
+        migrations.RunPython(create_user_uuid, backwards),
         migrations.AlterField(
             model_name="user",
             name="uuid",