Alerting: Improve performance of the setting GUID during migration (#101800)

pkg/services/sqlstore/migrations/ualert/alert_rule_version_guid_mig.go

@@ -1,9 +1,13 @@
 package ualert
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/google/uuid"
 
 	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
+	"github.com/grafana/grafana/pkg/util"
 	"xorm.io/xorm"
 )
 
@@ -58,26 +62,59 @@ func (c setRuleGuidMigration) SQL(migrator.Dialect) string {
 }
 
 func (c setRuleGuidMigration) Exec(sess *xorm.Session, mg *migrator.Migrator) error {
-	var results []string
-	if err := sess.SQL("SELECT uid FROM alert_rule").Find(&results); err != nil {
-		return err
-	}
-	if len(results) == 0 {
-		mg.Logger.Debug("no rules found")
-		return nil
-	}
-	for _, uid := range results {
-		u := uuid.NewString()
-		_, err := sess.Exec("UPDATE alert_rule_version SET rule_guid = ? WHERE rule_uid = ?", u, uid)
-		if err != nil {
-			mg.Logger.Error("Failed to update alert_rule_version table", "error", err)
+	var lastId *int64
+	for {
+		var results []int64
+		qq := sess.Table(`alert_rule`).Select("id").OrderBy("id").Limit(500)
+		if lastId != nil {
+			qq = qq.Where("id > ?", lastId)
+		}
+		if err := qq.Find(&results); err != nil {
 			return err
 		}
-		_, err = sess.Exec("UPDATE alert_rule SET guid = ? WHERE uid = ?", u, uid)
+		if len(results) == 0 {
+			break
+		}
+		bd := strings.Builder{}
+		for idx, id := range results {
+			u := uuid.NewString()
+			if idx == 0 {
+				bd.WriteString(fmt.Sprintf("SELECT %d as id, '%s' as guid", id, u))
+				continue
+			}
+			bd.WriteString(fmt.Sprintf(" UNION ALL SELECT %d, '%s' ", id, u))
+		}
+		var q string
+		if mg.Dialect.DriverName() == migrator.MySQL {
+			q = fmt.Sprintf(`UPDATE alert_rule AS ar
+			INNER JOIN (%s) AS t ON ar.id = t.id
+			SET ar.guid = t.guid;`, bd.String())
+		} else {
+			q = fmt.Sprintf(`UPDATE alert_rule SET guid = t.guid FROM (%s) AS t WHERE alert_rule.id = t.id`, bd.String())
+		}
+		_, err := sess.Exec(q)
 		if err != nil {
 			mg.Logger.Error("Failed to update alert_rule table", "error", err)
 			return err
 		}
+		lastId = util.Pointer(results[len(results)-1])
+	}
+
+	q := `UPDATE alert_rule_version
+		SET rule_guid = alert_rule.guid
+		FROM alert_rule
+		WHERE alert_rule.uid = alert_rule_version.rule_uid 
+		  AND alert_rule.org_id = alert_rule_version.rule_org_id;`
+
+	if mg.Dialect.DriverName() == migrator.MySQL {
+		q = `UPDATE alert_rule_version AS arv
+			INNER JOIN alert_rule AS ar ON arv.rule_uid = ar.uid AND arv.rule_org_id = ar.org_id
+			SET arv.rule_guid = ar.guid;`
+	}
+	_, err := sess.Exec(q)
+	if err != nil {
+		mg.Logger.Error("Failed to update alert_rule_version table with GUIDs from alert_rule table", "error", err)
+		return err
 	}
 	return nil
 }