Nested Folders: Use recursive query if the driver supports it (#58178)

* Nested Folders: Try first recursive query and fallback if it's not supported

* Apply suggestion from code review

Fix error msgID

pkg/services/folder/folderimpl/sqlstore.go

@@ -2,14 +2,16 @@ package folderimpl
 
 import (
 	"context"
+	"errors"
 	"strings"
 	"time"
 
+	"github.com/VividCortex/mysqlerr"
+	"github.com/go-sql-driver/mysql"
 	"github.com/grafana/grafana/pkg/infra/db"
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/services/folder"
-	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
 	"github.com/grafana/grafana/pkg/setting"
 	"github.com/grafana/grafana/pkg/util"
 )
@@ -183,9 +185,6 @@ func (ss *sqlStore) Get(ctx context.Context, q folder.GetFolderQuery) (*folder.F
 
 func (ss *sqlStore) GetParents(ctx context.Context, q folder.GetParentsQuery) ([]*folder.Folder, error) {
 	var folders []*folder.Folder
-	if ss.db.GetDBType() == migrator.MySQL {
-		return ss.getParentsMySQL(ctx, q)
-	}
 
 	recQuery := `
 		WITH RECURSIVE RecQry AS (
@@ -195,14 +194,23 @@ func (ss *sqlStore) GetParents(ctx context.Context, q folder.GetParentsQuery) ([
 		SELECT * FROM RecQry;
 	`
 
-	err := ss.db.WithDbSession(ctx, func(sess *db.Session) error {
+	if err := ss.db.WithDbSession(ctx, func(sess *db.Session) error {
 		err := sess.SQL(recQuery, q.UID, q.OrgID).Find(&folders)
 		if err != nil {
 			return folder.ErrDatabaseError.Errorf("failed to get folder parents: %w", err)
 		}
 		return nil
-	})
-	return util.Reverse(folders[1:]), err
+	}); err != nil {
+		var driverErr *mysql.MySQLError
+		if errors.As(err, &driverErr) {
+			if driverErr.Number == mysqlerr.ER_PARSE_ERROR {
+				ss.log.Debug("recursive CTE subquery is not supported; it fallbacks to the iterative implementation")
+				return ss.getParentsMySQL(ctx, q)
+			}
+		}
+		return nil, err
+	}
+	return util.Reverse(folders[1:]), nil
 }
 
 func (ss *sqlStore) GetChildren(ctx context.Context, q folder.GetTreeQuery) ([]*folder.Folder, error) {
@@ -228,20 +236,32 @@ func (ss *sqlStore) GetChildren(ctx context.Context, q folder.GetTreeQuery) ([]*
 	return folders, err
 }
 
-func (ss *sqlStore) getParentsMySQL(ctx context.Context, cmd folder.GetParentsQuery) ([]*folder.Folder, error) {
-	var foldrs []*folder.Folder
-	var foldr *folder.Folder
-	err := ss.db.WithDbSession(ctx, func(sess *db.Session) error {
-		uid := cmd.UID
-		for uid != folder.GeneralFolderUID && len(foldrs) < 8 {
-			err := sess.Where("uid=? AND org_id=>", uid, cmd.OrgID).Find(foldr)
+func (ss *sqlStore) getParentsMySQL(ctx context.Context, cmd folder.GetParentsQuery) (folders []*folder.Folder, err error) {
+	err = ss.db.WithDbSession(ctx, func(sess *db.Session) error {
+		uid := ""
+		ok, err := sess.SQL("SELECT parent_uid FROM folder WHERE org_id=? AND uid=?", cmd.OrgID, cmd.UID).Get(&uid)
+		if err != nil {
+			return err
+		}
+		if !ok {
+			return folder.ErrFolderNotFound
+		}
+		for {
+			f := &folder.Folder{}
+			ok, err := sess.SQL("SELECT * FROM folder WHERE org_id=? AND uid=?", cmd.OrgID, uid).Get(f)
 			if err != nil {
-				return folder.ErrDatabaseError.Errorf("failed to get folder parents: %w", err)
+				return err
+			}
+			if !ok {
+				break
+			}
+			folders = append(folders, f)
+			uid = f.ParentUID
+			if len(folders) > folder.MaxNestedFolderDepth {
+				return folder.ErrFolderTooDeep
 			}
-			foldrs = append(foldrs, foldr)
-			uid = foldr.ParentUID
 		}
 		return nil
 	})
-	return foldrs, err
+	return folders, err
 }

pkg/services/folder/model.go

@@ -10,6 +10,7 @@ var ErrMaximumDepthReached = errutil.NewBase(errutil.StatusBadRequest, "folder.m
 var ErrBadRequest = errutil.NewBase(errutil.StatusBadRequest, "folder.bad-request")
 var ErrDatabaseError = errutil.NewBase(errutil.StatusInternal, "folder.database-error")
 var ErrInternal = errutil.NewBase(errutil.StatusInternal, "folder.internal")
+var ErrFolderTooDeep = errutil.NewBase(errutil.StatusInternal, "folder.too-deep")
 
 const (
 	GeneralFolderUID     = "general"