Use bulk_update() to speed up VCID migration #811

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

vulnerabilities/migrations/0023_vcid_migration.py

@@ -12,9 +12,17 @@ class Migration(migrations.Migration):
 
     def save_vulnerability_id(apps, schema_editor):
         Vulnerabilities = apps.get_model("vulnerabilities", "Vulnerability")
+        updatables = []
         for vulnerability in Vulnerabilities.objects.filter(~Q(vulnerability_id__startswith="VCID-")):
             vulnerability.vulnerability_id = build_vcid()
-            vulnerability.save()
+            updatables.append(vulnerability)
+        # update in bulk, 500 at a time
+        updated = Vulnerabilities.objects.bulk_update(
+            objs=updatables, 
+            fields=["vulnerability_id"], 
+            batch_size=500,
+        )
+        print(f"Migrated {updated} vulnerabilities to new VCID")
 
     operations = [
         migrations.RunPython(save_vulnerability_id, migrations.RunPython.noop)