adds test

flow/connectors/postgres/qrep.go

@@ -230,6 +230,9 @@ func (c *PostgresConnector) getMinMaxValues(
 ) (interface{}, interface{}, error) {
 	var minValue, maxValue interface{}
 	quotedWatermarkColumn := fmt.Sprintf("\"%s\"", config.WatermarkColumn)
+	if config.WatermarkColumn == "xmin" {
+		quotedWatermarkColumn = fmt.Sprintf("%s::text::bigint", quotedWatermarkColumn)
+	}
 	// Get the maximum value from the database
 	maxQuery := fmt.Sprintf("SELECT MAX(%[1]s) FROM %[2]s", quotedWatermarkColumn, config.WatermarkTable)
 	row := tx.QueryRow(c.ctx, maxQuery)

flow/e2e/snowflake/qrep_flow_sf_test.go

@@ -212,6 +212,49 @@ func (s *PeerFlowE2ETestSuiteSF) Test_Complete_QRep_Flow_Avro_SF_S3() {
 	env.AssertExpectations(s.T())
 }
 
+func (s *PeerFlowE2ETestSuiteSF) Test_Complete_QRep_Flow_XMIN_SF_Append() {
+	env := s.NewTestWorkflowEnvironment()
+	e2e.RegisterWorkflowsAndActivities(env)
+
+	numRows := 10
+
+	tblName := "test_qrep_flow_avro_sf_xmin_append"
+	s.setupSourceTable(tblName, numRows)
+	s.setupSFDestinationTable(tblName)
+
+	dstSchemaQualified := fmt.Sprintf("%s.%s", s.sfHelper.testSchemaName, tblName)
+
+	query := fmt.Sprintf("SELECT * FROM e2e_test_%s.%s WHERE xmin::text::bigint BETWEEN {{.start}} AND {{.end}}",
+		snowflakeSuffix, tblName)
+
+	qrepConfig, err := e2e.CreateQRepWorkflowConfig(
+		"test_qrep_flow_avro_sf_xmin",
+		fmt.Sprintf("e2e_test_%s.%s", snowflakeSuffix, tblName),
+		dstSchemaQualified,
+		query,
+		protos.QRepSyncMode_QREP_SYNC_MODE_STORAGE_AVRO,
+		s.sfHelper.Peer,
+		"",
+	)
+
+	qrepConfig.WatermarkColumn = "xmin"
+	s.NoError(err)
+
+	e2e.RunQrepFlowWorkflow(env, qrepConfig)
+
+	// Verify workflow completes without error
+	s.True(env.IsWorkflowCompleted())
+
+	// assert that error contains "invalid connection configs"
+	err = env.GetWorkflowError()
+	s.NoError(err)
+
+	sel := e2e.GetOwnersSelectorString()
+	s.compareTableContentsSF(tblName, sel, true)
+
+	env.AssertExpectations(s.T())
+}
+
 func (s *PeerFlowE2ETestSuiteSF) Test_Complete_QRep_Flow_Avro_SF_S3_Integration() {
 	env := s.NewTestWorkflowEnvironment()
 	e2e.RegisterWorkflowsAndActivities(env)