update lock on trans

dtmsvr/storage/sql/sql.go

@@ -8,6 +8,8 @@
 package sql
 
 import (
+	"database/sql"
+	"errors"
 	"fmt"
 	"math"
 	"time"
@@ -159,23 +161,26 @@ func (s *Store) LockOneGlobalTrans(expireIn time.Duration) *storage.TransGlobalS
 	db := dbGet()
 	owner := shortuuid.New()
 	nextCronTime := getTimeStr(int64(expireIn / time.Second))
-	where := map[string]string{
-		dtmimp.DBTypeMysql:    fmt.Sprintf(`next_cron_time < '%s' and status in ('prepared', 'aborting', 'submitted') limit 1`, nextCronTime),
-		dtmimp.DBTypePostgres: fmt.Sprintf(`id in (select id from trans_global where next_cron_time < '%s' and status in ('prepared', 'aborting', 'submitted') limit 1 )`, nextCronTime),
+	where := fmt.Sprintf(`next_cron_time < '%s' and status in ('prepared', 'aborting', 'submitted')`, nextCronTime)
+
+	order := map[string]string{
+		dtmimp.DBTypeMysql:    `order by rand()`,
+		dtmimp.DBTypePostgres: `order by random()`,
 	}[conf.Store.Driver]
 
-	ssql := fmt.Sprintf(`select count(1) from trans_global where %s`, where)
-	var cnt int64
-	err := db.ToSQLDB().QueryRow(ssql).Scan(&cnt)
-	dtmimp.PanicIf(err != nil, err)
-	if cnt == 0 {
+	ssql := fmt.Sprintf(`select id from trans_global where %s %s limit 1`, where, order)
+	var id int64
+	err := db.ToSQLDB().QueryRow(ssql).Scan(&id)
+	if errors.Is(err, sql.ErrNoRows) {
 		return nil
 	}
+	dtmimp.PanicIf(err != nil, err)
 
-	sql := fmt.Sprintf(`UPDATE trans_global SET update_time='%s',next_cron_time='%s', owner='%s' WHERE %s`,
+	sql := fmt.Sprintf(`UPDATE trans_global SET update_time='%s',next_cron_time='%s', owner='%s' WHERE id=%d and %s`,
 		getTimeStr(0),
 		getTimeStr(conf.RetryInterval),
 		owner,
+		id,
 		where)
 	affected, err := dtmimp.DBExec(conf.Store.Driver, db.ToSQLDB(), sql)