Chore: Add function for detecting if the SQL driver supported CTEs (#64441)

* Add interface method for detecting if the SQL driver supported CTEs

* Update nested folder store to call RecursiveQueriesAreSupported()

pkg/infra/db/db.go

@@ -20,6 +20,9 @@ type DB interface {
 	GetSqlxSession() *session.SessionDB
 	InTransaction(ctx context.Context, fn func(ctx context.Context) error) error
 	Quote(value string) string
+	// RecursiveQueriesAreSupported runs a dummy recursive query and it returns true
+	// if the query runs successfully or false if it fails with mysqlerr.ER_PARSE_ERROR error or any other error
+	RecursiveQueriesAreSupported() (bool, error)
 }
 
 type Session = sqlstore.DBSession

pkg/infra/db/dbtest/dbtest.go

@@ -51,6 +51,10 @@ func (f *FakeDB) Quote(value string) string {
 	return ""
 }
 
+func (f *FakeDB) RecursiveQueriesAreSupported() (bool, error) {
+	return false, nil
+}
+
 // TODO: service-specific methods not yet split out ; to be removed
 func (f *FakeDB) UpdateTempUserWithEmailSent(ctx context.Context, cmd *tempuser.UpdateTempUserWithEmailSentCommand) error {
 	return f.ExpectedError

pkg/services/folder/folderimpl/sqlstore.go

@@ -2,13 +2,9 @@ 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/infra/slugify"
@@ -196,6 +192,12 @@ func (ss *sqlStore) GetParents(ctx context.Context, q folder.GetParentsQuery) ([
 		SELECT * FROM RecQry;
 	`
 
+	recursiveQueriesAreSupported, err := ss.db.RecursiveQueriesAreSupported()
+	if err != nil {
+		return nil, err
+	}
+	switch recursiveQueriesAreSupported {
+	case true:
 		if err := ss.db.WithDbSession(ctx, func(sess *db.Session) error {
 			err := sess.SQL(recQuery, q.UID, q.OrgID).Find(&folders)
 			if err != nil {
@@ -203,15 +205,12 @@ func (ss *sqlStore) GetParents(ctx context.Context, q folder.GetParentsQuery) ([
 			}
 			return nil
 		}); err != nil {
-		var driverErr *mysql.MySQLError
+			return nil, err
-		if errors.As(err, &driverErr) {
+		}
-			if driverErr.Number == mysqlerr.ER_PARSE_ERROR {
+	default:
 		ss.log.Debug("recursive CTE subquery is not supported; it fallbacks to the iterative implementation")
 		return ss.getParentsMySQL(ctx, q)
 	}
-		}
-		return nil, err
-	}
 
 	if len(folders) < 1 {
 		// the query is expected to return at least the same folder

pkg/services/sqlstore/sqlstore.go

@@ -2,6 +2,7 @@ package sqlstore
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net/url"
 	"os"
@@ -11,6 +12,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/VividCortex/mysqlerr"
 	"github.com/dlmiddlecote/sqlstats"
 	"github.com/go-sql-driver/mysql"
 	"github.com/jmoiron/sqlx"
@@ -52,6 +54,7 @@ type SQLStore struct {
 	skipEnsureDefaultOrgAndUser  bool
 	migrations                   registry.DatabaseMigrator
 	tracer                       tracing.Tracer
+	recursiveQueriesAreSupported *bool
 }
 
 func ProvideService(cfg *setting.Cfg, cacheService *localcache.CacheService, migrations registry.DatabaseMigrator, bus bus.Bus, tracer tracing.Tracer) (*SQLStore, error) {
@@ -476,6 +479,43 @@ func (ss *SQLStore) readConfig() error {
 	return nil
 }
 
+func (ss *SQLStore) RecursiveQueriesAreSupported() (bool, error) {
+	if ss.recursiveQueriesAreSupported != nil {
+		return *ss.recursiveQueriesAreSupported, nil
+	}
+	recursiveQueriesAreSupported := func() (bool, error) {
+		var result []int
+		if err := ss.WithDbSession(context.Background(), func(sess *DBSession) error {
+			recQry := `WITH RECURSIVE cte (n) AS
+			(
+			SELECT 1
+			UNION ALL
+			SELECT n + 1 FROM cte WHERE n < 2
+			)
+			SELECT * FROM cte;
+		`
+			err := sess.SQL(recQry).Find(&result)
+			return err
+		}); err != nil {
+			var driverErr *mysql.MySQLError
+			if errors.As(err, &driverErr) {
+				if driverErr.Number == mysqlerr.ER_PARSE_ERROR {
+					return false, nil
+				}
+			}
+			return false, err
+		}
+		return true, nil
+	}
+
+	areSupported, err := recursiveQueriesAreSupported()
+	if err != nil {
+		return false, err
+	}
+	ss.recursiveQueriesAreSupported = &areSupported
+	return *ss.recursiveQueriesAreSupported, nil
+}
+
 // ITestDB is an interface of arguments for testing db
 type ITestDB interface {
 	Helper()