Fix `Connection#disable_prepared_statements` loosing connection qualifier

lib/gitlab/database/connection.rb

@@ -88,7 +88,16 @@ module Gitlab
 
       # Disables prepared statements for the current database connection.
       def disable_prepared_statements
-        scope.establish_connection(config.merge(prepared_statements: false))
+        db_config_object = scope.connection_db_config
+        config = db_config_object.configuration_hash.merge(prepared_statements: false)
+
+        hash_config = ActiveRecord::DatabaseConfigurations::HashConfig.new(
+          db_config_object.env_name,
+          db_config_object.name,
+          config
+        )
+
+        scope.establish_connection(hash_config)
       end
 
       # Check whether the underlying database is in read-only mode

spec/lib/gitlab/database/connection_spec.rb

@@ -162,6 +162,12 @@ RSpec.describe Gitlab::Database::Connection do
       expect(connection.scope.connection.prepared_statements).to eq(false)
     end
 
+    it 'retains the connection name' do
+      connection.disable_prepared_statements
+
+      expect(connection.scope.connection_db_config.name).to eq('main')
+    end
+
     context 'with dynamic connection pool size' do
       before do
         connection.scope.establish_connection(connection.config.merge(pool: 7))