diff --git a/persist/sqldb/migrate.go b/persist/sqldb/migrate.go
index 45c908cc87de..193b20ccb887 100644
--- a/persist/sqldb/migrate.go
+++ b/persist/sqldb/migrate.go
@@ -25,6 +25,12 @@ type change interface {
 	apply(session db.Session) error
 }
 
+type noop struct{}
+
+func (s noop) apply(session db.Session) error {
+	return nil
+}
+
 func ternary(condition bool, left, right change) change {
 	if condition {
 		return left
@@ -258,6 +264,11 @@ func (m migrate) Exec(ctx context.Context) (err error) {
 		// add indexes for list archived workflow performance. #8836
 		ansiSQLChange(`create index argo_archived_workflows_i4 on argo_archived_workflows (startedat)`),
 		ansiSQLChange(`create index argo_archived_workflows_labels_i1 on argo_archived_workflows_labels (name,value)`),
+		// PostgreSQL only: convert argo_archived_workflows.workflow column to JSONB for performance. #13601
+		ternary(dbType == MySQL,
+			noop{},
+			ansiSQLChange(`alter table argo_archived_workflows alter column workflow set data type jsonb using workflow::jsonb`),
+		),
 	} {
 		err := m.applyChange(changeSchemaVersion, change)
 		if err != nil {