dumpling在导出含有tiflash副本的表时候会报错

[dba-kit (张天师)]

报错内容如下：

dump failed: sql:  ******* : Error 1105: other error for mpp stream: From MPP<query:441036080350232595,task:2>: DB::TiFlashException: Failed to register MPP Task MPP<query:441036080350232595,task:2>, reason: task has been registered

暂时可以通过加参数--params "tidb_isolation_read_engines=tikv"，强制让其从TiKV备份数据，这样能导出成功。

[lilinghai]

dumpling 的完整命令贴一下，出错时 tidb 完整的错误日志也可以发一下

[dba-kit (张天师)]

详细的报错堆栈在这里，命令很简单，就是全量备份一个带TiFlash副本的表，你可以在测试环境试一下，看有没有报错

github.com/pingcap/tidb/dumpling/export.(*tableData).Start
	github.com/pingcap/tidb/dumpling/export/ir_impl.go:207
github.com/pingcap/tidb/dumpling/export.(*Writer).WriteTableData.func1
	github.com/pingcap/tidb/dumpling/export/writer.go:210
github.com/pingcap/tidb/br/pkg/utils.WithRetry
	github.com/pingcap/tidb/br/pkg/utils/retry.go:52
github.com/pingcap/tidb/dumpling/export.(*Writer).WriteTableData
	github.com/pingcap/tidb/dumpling/export/writer.go:192
github.com/pingcap/tidb/dumpling/export.(*Writer).handleTask
	github.com/pingcap/tidb/dumpling/export/writer.go:115
github.com/pingcap/tidb/dumpling/export.(*Writer).run
	github.com/pingcap/tidb/dumpling/export/writer.go:93
github.com/pingcap/tidb/dumpling/export.(*Dumper).startWriters.func4
	github.com/pingcap/tidb/dumpling/export/dump.go:356
golang.org/x/sync/errgroup.(*Group).Go.func1
	golang.org/x/sync@v0.1.0/errgroup/errgroup.go:75
runtime.goexit
	runtime/asm_amd64.s:1594

[lilinghai]

先记录一个 issue 跟进下，目前看起来直接在 tidb 上执行失败的 query 没有问题，但是使用 dumpling 执行会有问题，可能 dumpling 有什么特殊的设置。https://github.com/pingcap/tidb/issues/43426