K8SPXC-1748: add checks before creating functions in collector

cmd/pitr/pxc/pxc.go

@@ -351,19 +351,27 @@ func (p *PXC) UninstallBinlogUDFComponent(ctx context.Context) error {
 }
 
 func (p *PXC) CreateCollectorFunctions(ctx context.Context) error {
-	_, err := p.db.ExecContext(ctx, "CREATE FUNCTION IF NOT EXISTS get_last_record_timestamp_by_binlog RETURNS INTEGER SONAME 'binlog_utils_udf.so'")
-	if err != nil {
-		return errors.Wrap(err, "create function get_first_record_timestamp_by_binlog")
+	m := map[string]string{
+		"get_last_record_timestamp_by_binlog":  "INTEGER",
+		"get_gtid_set_by_binlog":               "STRING",
+		"get_first_record_timestamp_by_binlog": "INTEGER",
 	}
 
-	_, err = p.db.ExecContext(ctx, "CREATE FUNCTION IF NOT EXISTS get_gtid_set_by_binlog RETURNS STRING SONAME 'binlog_utils_udf.so'")
-	if err != nil {
-		return errors.Wrap(err, "create function get_gtid_set_by_binlog")
-	}
+	for functionName, returnType := range m {
+		var x int
+		err := p.db.QueryRowContext(ctx, `SELECT 1 FROM mysql.func WHERE name = ? LIMIT 1`, functionName).Scan(&x)
+		if err != nil && !errors.Is(err, sql.ErrNoRows) {
+			return errors.Wrapf(err, "check if function %s exists", functionName)
+		}
+		if err == nil {
+			log.Printf("function %s already exists", functionName)
+			continue
+		}
 
-	_, err = p.db.ExecContext(ctx, "CREATE FUNCTION IF NOT EXISTS get_first_record_timestamp_by_binlog RETURNS INTEGER SONAME 'binlog_utils_udf.so'")
-	if err != nil {
-		return errors.Wrap(err, "create function get_first_record_timestamp_by_binlog")
+		createQ := fmt.Sprintf("CREATE FUNCTION IF NOT EXISTS %s RETURNS %s SONAME 'binlog_utils_udf.so'", functionName, returnType)
+		if _, err := p.db.ExecContext(ctx, createQ); err != nil {
+			return errors.Wrapf(err, "create function %s", functionName)
+		}
 	}
 
 	return nil

e2e-tests/pitr/run

@@ -79,6 +79,20 @@ main() {
 	cluster="pitr"
 	spinup_pxc "$cluster" "$test_dir/conf/$cluster.yml"
 
+	kubectl_bin delete pod -l "app.kubernetes.io/component=pitr"
+	sleep 30
+	pitr_pod=$(
+		kubectl_bin get pods \
+			--selector="app.kubernetes.io/component=pitr" \
+			-o 'jsonpath={.items[].metadata.name}'
+	)
+	wait_pod "$pitr_pod"
+	function_exists_count=$(kubectl_bin logs -l "app.kubernetes.io/component=pitr" --tail=-1 2>/dev/null | grep -c 'already exists')
+	if [ "$function_exists_count" -eq 0 ]; then
+		echo "There are no 'function ... already exists' logs"
+		exit 1
+	fi
+
 	run_backup "$cluster" "on-pitr-minio"
 
 	# Temporarily skipping this check