Data Migration Monitoring Metrics
If your DM cluster is deployed using TiUP, the monitoring system is also deployed at the same time. This document describes the monitoring metrics provided by DM-worker.
Task
In the Grafana dashboard, the default name of DM is DM-task.
overview
Overview contains some monitoring metrics of all the DM-worker and DM-master instances or sources in the currently selected task. The current default alert rule is only for a single DM-worker/DM-master instance/source.
| Metric name | Description | Alert | Severity level |
|---|---|---|---|
| task state | The state of subtasks for migration | N/A | N/A |
| storage capacity | The total storage capacity of the disk occupied by relay logs | N/A | N/A |
| storage remain | The remaining storage capacity of the disk occupied by relay logs | N/A | N/A |
| binlog file gap between master and relay | The number of binlog files by which the relay processing unit is behind the upstream master | N/A | N/A |
| load progress | The percentage of the completed loading process of the load unit. The value is between 0%~100% | N/A | N/A |
| binlog file gap between master and syncer | The number of binlog files by which the binlog replication unit is behind the upstream master | N/A | N/A |
| shard lock resolving | Whether the current subtask is waiting for sharding DDL migration. A value greater than 0 means that the current subtask is waiting for sharding DDL migration | N/A | N/A |
Operation errors
| Metric name | Description | Alert | Severity level |
|---|---|---|---|
| before any operate error | The number of errors before any operation | N/A | N/A |
| source bound error | The number of errors of data source binding operations | N/A | N/A |
| start error | The number of errors during the start of a subtask | N/A | N/A |
| pause error | The number of errors during the pause of a subtask | N/A | N/A |
| resume error | The number of errors during the resuming of a subtask | N/A | N/A |
| auto-resume error | The number of errors during the auto-resuming of a subtask | N/A | N/A |
| update error | The number of errors during the update of a subtask | N/A | N/A |
| stop error | The number of errors during the stop of a subtask | N/A | N/A |
High availability
| Metric name | Description | Alert | Severity level |
|---|---|---|---|
| number of dm-masters start leader components per minute | The number of DM-master attempts to enable leader related components per minute | N/A | N/A |
| number of workers in different state | The number of DM-workers in different states | Some DM-worker(s) has (have) been offline for more than one hour | critical |
| workers' state | The state of the DM-worker | N/A | N/A |
| number of worker event error | The number of different types of DM-worker errors | N/A | N/A |
| shard ddl error per minute | The number of different types of sharding DDL errors per minute | Any sharding DDL error occurs | critical |
| number of pending shard ddl | The number of pending sharding DDL operations | Any pending sharding DDL operation has existed for more than one hour | critical |
Task state
| Metric name | Description | Alert | Severity level |
|---|---|---|---|
| task state | The state of subtasks | An alert occurs when the subtask has been in the Paused state for more than 20 minutes | critical |
Dump/Load unit
The following metrics show only when task-mode is in the full or all mode.
| Metric name | Description | Alert | Severity level |
|---|---|---|---|
| dump progress | The percentage of the completed dumping process of the dump unit. The value range is 0%~100% | N/A | N/A |
| load progress | The percentage of the completed loading process of the load unit. The value range is 0%~100% | N/A | N/A |
| checksum progress | The percentage of the completed checksum process after the load unit finishes dumping. The value range is 0%~100% | N/A | N/A |
| total bytes for load unit | The bytes processed in the parsing, in generating data KV, and in generating index KV stages of the import process by the load unit | N/A | N/A |
| chunk process duration | The duration of the load unit processing the data source file chunk (in seconds) | N/A | N/A |
| data file size | The total size of the data files (includes the INSERT INTO statement) in the full data imported by the load unit | N/A | N/A |
| dump process exits with error | The dump unit encounters an error within the DM-worker and exits | Immediate alerts | critical |
| load process exits with error | The load unit encounters an error within the DM-worker and exits | Immediate alerts | critical |
Binlog replication
The following metrics show only when task-mode is in the incremental or all mode.
| Metric name | Description | Alert | Severity level |
|---|---|---|---|
| remaining time to sync | The predicted remaining time it takes for syncer to be completely migrated with the upstream master (in minutes) | N/A | N/A |
| replicate lag gauge | The latency time it takes to replicate the binlog from upstream to downstream (in seconds) | N/A | N/A |
| replicate lag histogram | The histogram of replicating the binlog from upstream to downstream (in seconds). Note that due to different statistical mechanisms, the data might be inaccurate | N/A | N/A |
| process exist with error | The binlog replication unit encounters an error within the DM-worker and exits | Immediate alerts | critical |
| binlog file gap between master and syncer | The number of binlog files by which the syncer processing unit is behind the upstream master | An alert occurs when the number of binlog files by which the syncer processing unit is behind the upstream master exceeds one (>1) and the condition lasts over 10 minutes | critical |
| binlog file gap between relay and syncer | The number of binlog files by which syncer is behind relay | An alert occurs when the number of binlog files by which the syncer processing unit is behind the relay processing unit exceeds one (>1) and the condition lasts over 10 minutes | critical |
| binlog event QPS | The number of binlog events received per unit of time (this number does not include the events that need to be skipped) | N/A | N/A |
| skipped binlog event QPS | The number of binlog events received per unit of time that need to be skipped | N/A | N/A |
| read binlog event duration | The duration that the binlog replication unit reads the binlog from the relay log or the upstream MySQL (in seconds) | N/A | N/A |
| transform binlog event duration | The duration that the binlog replication unit parses and transforms the binlog into SQL statements (in seconds) | N/A | N/A |
| dispatch binlog event duration | The duration that the binlog replication unit dispatches a binlog event (in seconds) | N/A | N/A |
| transaction execution latency | The duration that the binlog replication unit executes the transaction to the downstream (in seconds) | N/A | N/A |
| binlog event size | The size of a binlog event that the binlog replication unit reads from the relay log or the upstream MySQL | N/A | N/A |
| DML queue remain length | The length of the remaining DML job queue | N/A | N/A |
| total sqls jobs | The number of newly added jobs per unit of time | N/A | N/A |
| finished sqls jobs | The number of finished jobs per unit of time | N/A | N/A |
| statement execution latency | The duration that the binlog replication unit executes the statement to the downstream (in seconds) | N/A | N/A |
| add job duration | The duration that the binlog replication unit adds a job to the queue (in seconds) | N/A | N/A |
| DML conflict detect duration | The duration that the binlog replication unit detects the conflict in DML (in seconds) | N/A | N/A |
| skipped event duration | The duration that the binlog replication unit skips a binlog event (in seconds) | N/A | N/A |
| unsynced tables | The number of tables that have not received the shard DDL statement in the current subtask | N/A | N/A |
| shard lock resolving | Whether the current subtask is waiting for the shard DDL lock to be resolved. A value greater than 0 indicates that it is waiting for the shard DDL lock to be resolved | N/A | N/A |
| ideal QPS | The highest QPS that can be achieved when the running time of DM is 0 | N/A | N/A |
| binlog event row | The number of rows in a binlog event | N/A | N/A |
| finished transaction total | The number of finished transactions in total | N/A | N/A |
| replication transaction batch | The number of sql rows in the transaction executed to the downstream | N/A | N/A |
| flush checkpoints time interval | The time interval for flushing the checkpoints (in seconds) | N/A | N/A |
Relay log
| Metric name | Description | Alert | Severity level |
|---|---|---|---|
| storage capacity | The storage capacity of the disk occupied by the relay log | N/A | N/A |
| storage remain | The remaining storage capacity of the disk occupied by the relay log | An alert is needed once the value is smaller than 10G | critical |
| process exits with error | The relay log encounters an error within the DM-worker and exits | Immediate alerts | critical |
| relay log data corruption | The number of corrupted relay log files | Immediate alerts | emergency |
| fail to read binlog from master | The number of errors encountered when the relay log reads the binlog from the upstream MySQL | Immediate alerts | critical |
| fail to write relay log | The number of errors encountered when the relay log writes the binlog to disks | Immediate alerts | critical |
| binlog file index | The largest index number of relay log files. For example, "value = 1" indicates "relay-log.000001" | N/A | N/A |
| binlog file gap between master and relay | The number of binlog files in the relay log that are behind the upstream master | An alert occurs when the number of binlog files by which the relay processing unit is behind the upstream master exceeds one (>1) and the condition lasts over 10 minutes | critical |
| binlog pos | The write offset of the latest relay log file | N/A | N/A |
| read binlog event duration | The duration that the relay log reads binlog from the upstream MySQL (in seconds) | N/A | N/A |
| write relay log duration | The duration that the relay log writes binlog into the disks each time (in seconds) | N/A | N/A |
| binlog event size | The size of a single binlog event that the relay log writes into the disks | N/A | N/A |
Instance
In the Grafana dashboard, the default name of an instance is DM-instance.
Relay log
| Metric name | Description | Alert | Severity level |
|---|---|---|---|
| storage capacity | The total storage capacity of the disk occupied by the relay log | N/A | N/A |
| storage remain | The remaining storage capacity within the disk occupied by the relay log | An alert occurs once the value is smaller than 10G | critical |
| process exits with error | The relay log encounters an error in DM-worker and exits | Immediate alerts | critical |
| relay log data corruption | The number of corrupted relay logs | Immediate alerts | emergency |
| fail to read binlog from master | The number of errors encountered when relay log reads the binlog from the upstream MySQL | Immediate alerts | critical |
| fail to write relay log | The number of errors encountered when the relay log writes the binlog to disks | Immediate alerts | critical |
| binlog file index | The largest index number of relay log files. For example, "value = 1" indicates "relay-log.000001" | N/A | N/A |
| binlog file gap between master and relay | The number of binlog files by which the relay processing unit is behind the upstream master | An alert occurs when the number of binlog files by which the relay processing unit is behind the upstream master exceeds one (>1) and the condition lasts over 10 minutes | critical |
| binlog pos | The write offset of the latest relay log file | N/A | N/A |
| read binlog duration | The duration that the relay log reads the binlog from the upstream MySQL (in seconds) | N/A | N/A |
| write relay log duration | The duration that the relay log writes the binlog into the disk each time (in seconds) | N/A | N/A |
| binlog size | The size of a single binlog event that the relay log writes into the disks | N/A | N/A |
Task
| Metric name | Description | Alert | Severity level |
|---|---|---|---|
| task state | The state of subtasks for migration | An alert occurs when the subtask has been paused for more than 10 minutes | critical |
| load progress | The percentage of the completed loading process of the load unit. The value range is 0%~100% | N/A | N/A |
| binlog file gap between master and syncer | The number of binlog files by which the binlog replication unit is behind the upstream master | N/A | N/A |
| shard lock resolving | Whether the current subtask is waiting for sharding DDL migration. A value greater than 0 means that the current subtask is waiting for sharding DDL migration | N/A | N/A |