Query Task Status in TiDB Data Migration
This document introduces how to use the query-status command to query the task status, and the subtask status of DM.
Query result
» query-status
{
"result": true, # Whether the query is successful.
"msg": "", # Describes the reason for the unsuccessful query.
"tasks": [ # Migration task list.
{
"taskName": "test", # The task name.
"taskStatus": "Running", # The status of the task.
"sources": [ # The upstream MySQL list.
"mysql-replica-01",
"mysql-replica-02"
]
},
{
"taskName": "test2",
"taskStatus": "Paused",
"sources": [
"mysql-replica-01",
"mysql-replica-02"
]
}
]
}
For detailed descriptions of taskStatus under the tasks section, refer to Task status.
It is recommended that you use query-status by the following steps:
- Use
query-statusto check whether each on-going task is in the normal state. - If any error occurs in a task, use the
query-status <taskName>command to see detailed error information.<taskName>in this command indicates the name of the task that encounters the error.
Task status
The status of a DM migration task depends on the status of each subtask assigned to DM-worker. For detailed descriptions of subtask status, see Subtask status. The table below shows how the subtask status is related to task status.
| Subtask status in a task | Task status |
|---|---|
One subtask is in the paused state and error information is returned. | Error - Some error occurred in subtask |
One subtask in the Sync phase is in the Running state but its Relay processing unit is not running (in the Error/Paused/Stopped state). | Error - Relay status is Error/Paused/Stopped |
One subtask is in the Paused state and no error information is returned. | Paused |
All subtasks are in the New state. | New |
All subtasks are in the Finished state. | Finished |
All subtasks are in the Stopped state. | Stopped |
| Other situations | Running |
Detailed query result
» query-status test
» query-status
{
"result": true, # Whether the query is successful.
"msg": "", # Describes the cause for the unsuccessful query.
"sources": [ # The upstream MySQL list.
{
"result": true,
"msg": "",
"sourceStatus": { # The information of the upstream MySQL databases.
"source": "mysql-replica-01",
"worker": "worker1",
"result": null,
"relayStatus": null
},
"subTaskStatus": [ # The information of all subtasks of upstream MySQL databases.
{
"name": "test", # The name of the subtask.
"stage": "Running", # The running status of the subtask, including "New", "Running", "Paused", "Stopped", and "Finished".
"unit": "Sync", # The processing unit of DM, including "Check", "Dump", "Load", and "Sync".
"result": null, # Displays the error information if a subtask fails.
"unresolvedDDLLockID": "test-`test`.`t_target`", # The sharding DDL lock ID, used for manually handling the sharding DDL
# lock in the abnormal condition.
"sync": { # The replication information of the `Sync` processing unit. This information is about the
# same component with the current processing unit.
"totalEvents": "12", # The total number of binlog events that are replicated in this subtask.
"totalTps": "1", # The number of binlog events that are replicated in this subtask per second.
"recentTps": "1", # The number of binlog events that are replicated in this subtask in the last one second.
"masterBinlog": "(bin.000001, 3234)", # The binlog position in the upstream database.
"masterBinlogGtid": "c0149e17-dff1-11e8-b6a8-0242ac110004:1-14", # The GTID information in the upstream database.
"syncerBinlog": "(bin.000001, 2525)", # The position of the binlog that has been replicated
# in the `Sync` processing unit.
"syncerBinlogGtid": "", # The binlog position replicated using GTID.
"blockingDDLs": [ # The DDL list that is blocked currently. It is not empty only when all the upstream tables of this
# DM-worker are in the "synced" status. In this case, it indicates the sharding DDL statements to be executed or that are skipped.
"USE `test`; ALTER TABLE `test`.`t_target` DROP COLUMN `age`;"
],
"unresolvedGroups": [ # The sharding group that is not resolved.
{
"target": "`test`.`t_target`", # The downstream database table to be replicated.
"DDLs": [
"USE `test`; ALTER TABLE `test`.`t_target` DROP COLUMN `age`;"
],
"firstPos": "(bin|000001.000001, 3130)", # The starting position of the sharding DDL statement.
"synced": [ # The upstream sharded table whose executed sharding DDL statement has been read by the `Sync` unit.
"`test`.`t2`"
"`test`.`t3`"
"`test`.`t1`"
],
"unsynced": [ # The upstream table that has not executed this sharding DDL
# statement. If any upstream tables have not finished replication,
# `blockingDDLs` is empty.
]
}
],
"synced": false # Whether the incremental replication catches up with the upstream and has the same binlog position as that in the
# upstream. The save point is not refreshed in real time in the `Sync` background, so "false" of "synced"
# does not always mean a replication delay exits.
}
}
]
},
{
"result": true,
"msg": "",
"sourceStatus": {
"source": "mysql-replica-02",
"worker": "worker2",
"result": null,
"relayStatus": null
},
"subTaskStatus": [
{
"name": "test",
"stage": "Running",
"unit": "Load",
"result": null,
"unresolvedDDLLockID": "",
"load": { # The replication information of the `Load` processing unit.
"finishedBytes": "115", # The number of bytes that have been loaded.
"totalBytes": "452", # The total number of bytes that need to be loaded.
"progress": "25.44 %" # The progress of the loading process.
}
}
]
},
{
"result": true,
"sourceStatus": {
"source": "mysql-replica-03",
"worker": "worker3",
"result": null,
"relayStatus": null
},
"subTaskStatus": [
{
"name": "test",
"stage": "Paused",
"unit": "Load",
"result": { # The error example.
"isCanceled": false,
"errors": [
{
"Type": "ExecSQL",
"msg": "Error 1062: Duplicate entry '1155173304420532225' for key 'PRIMARY'\n/home/jenkins/workspace/build_dm/go/src/github.com/pingcap/tidb-enterprise-tools/loader/db.go:160: \n/home/jenkins/workspace/build_dm/go/src/github.com/pingcap/tidb-enterprise-tools/loader/db.go:105: \n/home/jenkins/workspace/build_dm/go/src/github.com/pingcap/tidb-enterprise-tools/loader/loader.go:138: file test.t1.sql"
}
],
"detail": null
},
"unresolvedDDLLockID": "",
"load": {
"finishedBytes": "0",
"totalBytes": "156",
"progress": "0.00 %"
}
}
]
}
]
}
For the status description and status switch relationship of "stage" of "subTaskStatus" of "sources", see the subtask status.
For operation details of "unresolvedDDLLockID" of "subTaskStatus" of "sources", see Handle Sharding DDL Locks Manually.
Subtask status
Status description
New:- The initial status.
- If the subtask does not encounter an error, it is switched to
Running; otherwise it is switched toPaused.
Running: The normal running status.Paused:- The paused status.
- If the subtask encounters an error, it is switched to
Paused. - If you run
pause-taskwhen the subtask is in theRunningstatus, the task is switched toPaused. - When the subtask is in this status, you can run the
resume-taskcommand to resume the task.
Stopped:- The stopped status.
- If you run
stop-taskwhen the subtask is in theRunningorPausedstatus, the task is switched toStopped. - When the subtask is in this status, you cannot use
resume-taskto resume the task.
Finished:- The finished subtask status.
- Only when the full replication subtask is finished normally, the task is switched to this status.
Status switch diagram
error occurs
New --------------------------------|
| |
| resume-task |
| |----------------------------| |
| | | |
| | | |
v v error occurs | v
Finished <-------------- Running -----------------------> Paused
^ | or pause-task |
| | |
start task | | stop task |
| | |
| v stop task |
Stopped <-------------------------|