Query Status

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:

1. Use query-status to check whether each on-going task is in the normal state.
2. 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.

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 to Paused.

• Running: The normal running status.

• Paused:

  • The paused status.
  • If the subtask encounters an error, it is switched to Paused.
  • If you run pause-task when the subtask is in the Running status, the task is switched to Paused.
  • When the subtask is in this status, you can run the resume-task command to resume the task.

• Stopped:

  • The stopped status.
  • If you run stop-task when the subtask is in the Running or Paused status, the task is switched to Stopped.
  • When the subtask is in this status, you cannot use resume-task to 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 <-------------------------|