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- 【TiDB 版本】：3.0.9
- 【问题描述】：我从上游mysql通过dm同步到tidb从库，如下sql产生了ddl lock，导致主从同步停止，请问这个是什么原因呢，如何避免？上游mysql到tidb从库的表是一一对应。
task任务的状态如下：
“subTaskStatus”: [
{
“name”: “test”,
“stage”: “Running”,
“unit”: “Sync”,
“result”: null,
“unresolvedDDLLockID”: “test-hollycas.tbl_order_info”,
“sync”: {
“totalEvents”: “23531259”,
“totalTps”: “801”,
“recentTps”: “0”,
“masterBinlog”: “(mysql-bin.002313, 689999667)”,
“masterBinlogGtid”: “”,
“syncerBinlog”: “(mysql-bin|000001.002283, 922100404)”,
“syncerBinlogGtid”: “”,
“blockingDDLs”: [
“ALTER TABLE hollycas.tbl_order_info ADD INDEX inx_create_time(create_time) USING BTREE”
],
“unresolvedGroups”: [
{
“target”: “hollycas.tbl_order_info”,
“DDLs”: [
“ALTER TABLE hollycas.tbl_order_info ADD INDEX inx_create_time(create_time) USING BTREE”
],
“firstPos”: “(mysql-bin|000001.002283, 922542857)”,
“synced”: [
“hollycas.tbl_order_info”
],
“unsynced”: [
]
}
],
“synced”: false
}
}
dm-worker日志如下：
[2020/03/06 18:48:37.743 +08:00] [INFO] [server.go:290] [request=FetchDDLInfo] [“ddl info”="task:“test” schema:“hollycas” table:“tbl_order_info” DDLs:“ALTER TABLE hollycas.tbl_order_info ADD INDEX inx_create_time(create_time) USING BTREE” "]
[2020/03/06 18:48:37.744 +08:00] [INFO] [server.go:307] [“receive DDLLockInfo”] [request=FetchDDLInfo] [“ddl lock info”=“task:“test” ID:“test-hollycas.tbl_order_info” “]
[2020/03/06 18:48:37.744 +08:00] [ERROR] [server.go:315] [“fail to record DDLLockInfo”] [request=FetchDDLInfo] [“ddl lock info”=“task:“test” ID:“test-hollycas.tbl_order_info” “] [error=”[code=40062:class=dm-worker:scope=internal:level=high] DDLLockInfo for task test already exists”] [errorVerbose=”[code=40062:class=dm-worker:scope=internal:level=high] DDLLockInfo for task test already exists\ngithub.com/pingcap/dm/pkg/terror.(*Error).Generate\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/pkg/terror/terror.go:232\ngithub.com/pingcap/dm/dm/worker.(*SubTask).SaveDDLLockInfo\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/dm/worker/subtask.go:529\ngithub.com/pingcap/dm/dm/worker.(*Worker).RecordDDLLockInfo\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/dm/worker/worker.go:445\ngithub.com/pingcap/dm/dm/worker.(*Server).FetchDDLInfo\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/dm/worker/server.go:311\ngithub.com/pingcap/dm/dm/pb._Worker_FetchDDLInfo_Handler\
\t/home/jenkins/agent/workspace/build_dm_master/go/src/github.com/pingcap/dm/dm/pb/dmworker.pb.go:3865\
google.golang.org/grpc.(*Server).processStreamingRPC\
\t/go/pkg/mod/google.golang.org/grpc@v1.25.1/server.go:1211\ngoogle.golang.org/grpc.(*Server).handleStream\
\t/go/pkg/mod/google.golang.org/grpc@v1.25.1/server.go:1291\ngoogle.golang.org/grpc.(*Server).serveStreams.func1.1\
\t/go/pkg/mod/google.golang.org/grpc@v1.25.1/server.go:722\
runtime.goexit\
\t/usr/local/go/src/runtime/asm_amd64.s:1357”]
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