Refs #31318 -- Optimized sqlmigrate by using MigrationLoader.

David-Wobrock · felixxm · commit 271e108b29a1 · 2020-03-09T08:34:41.000+01:00
Only loader from MigrationExecutor was used.
diff --git a/django/core/management/commands/sqlmigrate.py b/django/core/management/commands/sqlmigrate.py
@@ -1,8 +1,7 @@
 from django.apps import apps
 from django.core.management.base import BaseCommand, CommandError
 from django.db import DEFAULT_DB_ALIAS, connections
-from django.db.migrations.executor import MigrationExecutor
-from django.db.migrations.loader import AmbiguityError
+from django.db.migrations.loader import AmbiguityError, MigrationLoader
 
 
 class Command(BaseCommand):
@@ -33,8 +32,8 @@ def handle(self, *args, **options):
         # Get the database we're operating from
         connection = connections[options['database']]
 
-        # Load up an executor to get all the migration data
-        executor = MigrationExecutor(connection)
+        # Load up an loader to get all the migration data
+        loader = MigrationLoader(connection)
 
         # Resolve command-line arguments into a migration
         app_label, migration_name = options['app_label'], options['migration_name']
@@ -43,10 +42,10 @@ def handle(self, *args, **options):
             apps.get_app_config(app_label)
         except LookupError as err:
             raise CommandError(str(err))
-        if app_label not in executor.loader.migrated_apps:
+        if app_label not in loader.migrated_apps:
             raise CommandError("App '%s' does not have migrations" % app_label)
         try:
-            migration = executor.loader.get_migration_by_prefix(app_label, migration_name)
+            migration = loader.get_migration_by_prefix(app_label, migration_name)
         except AmbiguityError:
             raise CommandError("More than one migration matches '%s' in app '%s'. Please be more specific." % (
                 migration_name, app_label))
@@ -61,8 +60,8 @@ def handle(self, *args, **options):
 
         # Make a plan that represents just the requested migrations and show SQL
         # for it
-        plan = [(executor.loader.graph.nodes[target], options['backwards'])]
-        sql_statements = executor.loader.collect_sql(plan)
+        plan = [(loader.graph.nodes[target], options['backwards'])]
+        sql_statements = loader.collect_sql(plan)
         if not sql_statements and options['verbosity'] >= 1:
             self.stderr.write('No operations found.')
         return '\n'.join(sql_statements)
