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MySQL logoMySQL Prometheus Alert Rules

18 Prometheus alerting rules for MySQL.Exported via prometheus/mysqld_exporter.These rules cover critical and warning conditions — copy and paste the YAML into your Prometheus configuration.

⚠️

Alert thresholds depend on the nature of your applications. Some queries may have arbitrary tolerance thresholds. Building an efficient monitoring platform takes time. 😉

2.1.MySQL logoprometheus/mysqld_exporter(18 rules)

wget https://raw.githubusercontent.com/samber/awesome-prometheus-alerts/refs/heads/master/dist/rules/mysql/mysqld-exporter.yml
critical

2.1.1.MySQL down

MySQL instance is down on {{ $labels.instance }}

  # 1m delay allows a restart without triggering an alert.
- alert: MySQLDown
  expr: mysql_up == 0
  for: 1m
  labels:
    severity: critical
  annotations:
    summary: MySQL down (instance {{ $labels.instance }})
    description: "MySQL instance is down on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
critical

2.1.2.MySQL Slave IO thread not running

MySQL Slave IO thread not running on {{ $labels.instance }}

  # 1m delay allows a restart without triggering an alert.
- alert: MySQLSlaveIOThreadNotRunning
  expr: ( mysql_slave_status_slave_io_running and ON (instance) mysql_slave_status_master_server_id > 0 ) == 0
  for: 1m
  labels:
    severity: critical
  annotations:
    summary: MySQL Slave IO thread not running (instance {{ $labels.instance }})
    description: "MySQL Slave IO thread not running on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
critical

2.1.3.MySQL Slave SQL thread not running

MySQL Slave SQL thread not running on {{ $labels.instance }}

  # 1m delay allows a restart without triggering an alert.
- alert: MySQLSlaveSQLThreadNotRunning
  expr: ( mysql_slave_status_slave_sql_running and ON (instance) mysql_slave_status_master_server_id > 0) == 0
  for: 1m
  labels:
    severity: critical
  annotations:
    summary: MySQL Slave SQL thread not running (instance {{ $labels.instance }})
    description: "MySQL Slave SQL thread not running on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.4.MySQL too many connections (> 80%)

More than 80% of MySQL connections are in use on {{ $labels.instance }}

- alert: MySQLTooManyConnections(>80%)
  expr: max_over_time(mysql_global_status_threads_connected[1m]) / mysql_global_variables_max_connections * 100 > 80 and mysql_global_variables_max_connections > 0
  for: 2m
  labels:
    severity: warning
  annotations:
    summary: MySQL too many connections (> 80%) (instance {{ $labels.instance }})
    description: "More than 80% of MySQL connections are in use on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.5.MySQL high prepared statements utilization (> 80%)

High utilization of prepared statements (>80%) on {{ $labels.instance }}

- alert: MySQLHighPreparedStatementsUtilization(>80%)
  expr: max_over_time(mysql_global_status_prepared_stmt_count[1m]) / mysql_global_variables_max_prepared_stmt_count * 100 > 80 and mysql_global_variables_max_prepared_stmt_count > 0
  for: 2m
  labels:
    severity: warning
  annotations:
    summary: MySQL high prepared statements utilization (> 80%) (instance {{ $labels.instance }})
    description: "High utilization of prepared statements (>80%) on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.6.MySQL high threads running

More than 60% of MySQL connections are in running state on {{ $labels.instance }}

- alert: MySQLHighThreadsRunning
  expr: max_over_time(mysql_global_status_threads_running[1m]) / mysql_global_variables_max_connections * 100 > 60 and mysql_global_variables_max_connections > 0
  for: 2m
  labels:
    severity: warning
  annotations:
    summary: MySQL high threads running (instance {{ $labels.instance }})
    description: "More than 60% of MySQL connections are in running state on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
critical

2.1.7.MySQL Slave replication lag

MySQL replication lag on {{ $labels.instance }}

- alert: MySQLSlaveReplicationLag
  expr: ( (mysql_slave_status_seconds_behind_master - mysql_slave_status_sql_delay) and ON (instance) mysql_slave_status_master_server_id > 0 ) > 30
  for: 1m
  labels:
    severity: critical
  annotations:
    summary: MySQL Slave replication lag (instance {{ $labels.instance }})
    description: "MySQL replication lag on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
critical

2.1.8.MySQL heartbeat replication lag

MySQL replication lag on {{ $labels.instance }}

  # More reliable than seconds_behind_master since it measures actual wall-clock lag rather
  # than a value that can freeze during long-running statements. Requires mysqld_exporter's
  # optional --collect.heartbeat flag and a pt-heartbeat-style heartbeat table.
- alert: MySQLHeartbeatReplicationLag
  expr: mysql_heartbeat_now_timestamp_seconds - mysql_heartbeat_stored_timestamp_seconds > 30
  for: 1m
  labels:
    severity: critical
  annotations:
    summary: MySQL heartbeat replication lag (instance {{ $labels.instance }})
    description: "MySQL replication lag on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
critical

2.1.9.MySQL Galera node not ready

Galera cluster node {{ $labels.instance }} is not ready and is not accepting reads or writes.

- alert: MySQLGaleraNodeNotReady
  expr: mysql_global_status_wsrep_ready != 1
  for: 1m
  labels:
    severity: critical
  annotations:
    summary: MySQL Galera node not ready (instance {{ $labels.instance }})
    description: "Galera cluster node {{ $labels.instance }} is not ready and is not accepting reads or writes.\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.10.MySQL slow queries

MySQL server has some new slow queries ({{ $value }} in the last minute).

- alert: MySQLSlowQueries
  expr: increase(mysql_global_status_slow_queries[1m]) > 0
  for: 2m
  labels:
    severity: warning
  annotations:
    summary: MySQL slow queries (instance {{ $labels.instance }})
    description: "MySQL server has some new slow queries ({{ $value }} in the last minute).\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.11.MySQL InnoDB log waits

MySQL innodb log writes stalling ({{ $value }} waits/s)

  # 10 waits/s is a rough default; log-write stalls scale with your write workload and innodb_log_buffer_size — adjust based on your workload and buffer size.
- alert: MySQLInnoDBLogWaits
  expr: rate(mysql_global_status_innodb_log_waits[15m]) > 10
  for: 0m
  labels:
    severity: warning
  annotations:
    summary: MySQL InnoDB log waits (instance {{ $labels.instance }})
    description: "MySQL innodb log writes stalling ({{ $value }} waits/s)\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.12.MySQL too many open files

MySQL has too many open files, consider increase variables open_files_limit on {{ $labels.instance }}.

- alert: MySQLTooManyOpenFiles
  expr: mysql_global_status_innodb_num_open_files / mysql_global_variables_open_files_limit * 100 > 75 and mysql_global_variables_open_files_limit > 0
  for: 2m
  labels:
    severity: warning
  annotations:
    summary: MySQL too many open files (instance {{ $labels.instance }})
    description: "MySQL has too many open files, consider increase variables open_files_limit on {{ $labels.instance }}.\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.13.MySQL InnoDB history_len too long

MySQL history_len (undo log) too long on {{ $labels.instance }}

  # 50000 is a rough default; undo log length grows with long-running transactions and write volume — adjust based on your transaction patterns.
- alert: MySQLInnoDBHistory_lenTooLong
  expr: mysql_info_schema_innodb_metrics_transaction_trx_rseg_history_len > 50000
  for: 2m
  labels:
    severity: warning
  annotations:
    summary: MySQL InnoDB history_len too long (instance {{ $labels.instance }})
    description: "MySQL history_len (undo log) too long on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.14.MySQL Galera donor falling behind

Galera donor node {{ $labels.instance }} serving a state transfer has a growing receive queue ({{ $value }} entries), indicating it is falling behind the rest of the cluster.

  # 100-entry queue is a rough default; catch-up speed depends on your cluster's write throughput and network bandwidth — adjust based on your workload.
- alert: MySQLGaleraDonorFallingBehind
  expr: mysql_global_status_wsrep_local_state == 2 and mysql_global_status_wsrep_local_recv_queue > 100
  for: 2m
  labels:
    severity: warning
  annotations:
    summary: MySQL Galera donor falling behind (instance {{ $labels.instance }})
    description: "Galera donor node {{ $labels.instance }} serving a state transfer has a growing receive queue ({{ $value }} entries), indicating it is falling behind the rest of the cluster.\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
info

2.1.15.MySQL restarted

MySQL has just been restarted, less than one minute ago on {{ $labels.instance }}.

- alert: MySQLRestarted
  expr: mysql_global_status_uptime < 60
  for: 0m
  labels:
    severity: info
  annotations:
    summary: MySQL restarted (instance {{ $labels.instance }})
    description: "MySQL has just been restarted, less than one minute ago on {{ $labels.instance }}.\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
info

2.1.16.MySQL High QPS

MySQL is being overload with unusual QPS (> 10k QPS).

  # 10k QPS is a rough default; normal query volume scales with your application traffic — adjust based on your baseline.
- alert: MySQLHighQPS
  expr: rate(mysql_global_status_questions[1m]) > 10000
  for: 2m
  labels:
    severity: info
  annotations:
    summary: MySQL High QPS (instance {{ $labels.instance }})
    description: "MySQL is being overload with unusual QPS (> 10k QPS).\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.17.MySQL Galera node out of sync

Galera node {{ $labels.instance }} has unexpectedly fallen out of the Synced state (wsrep_local_state != 4), excluding nodes intentionally desynced for a state transfer or backup.

- alert: MySQLGaleraNodeOutOfSync
  expr: mysql_global_status_wsrep_local_state != 4 and mysql_global_variables_wsrep_desync == 0
  for: 2m
  labels:
    severity: warning
  annotations:
    summary: MySQL Galera node out of sync (instance {{ $labels.instance }})
    description: "Galera node {{ $labels.instance }} has unexpectedly fallen out of the Synced state (wsrep_local_state != 4), excluding nodes intentionally desynced for a state transfer or backup.\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
warning

2.1.18.MySQL InnoDB Force Recovery is enabled

MySQL InnoDB force recovery is enabled on {{ $labels.instance }}

- alert: MySQLInnoDBForceRecoveryIsEnabled
  expr: mysql_global_variables_innodb_force_recovery != 0
  for: 2m
  labels:
    severity: warning
  annotations:
    summary: MySQL InnoDB Force Recovery is enabled (instance {{ $labels.instance }})
    description: "MySQL InnoDB force recovery is enabled on {{ $labels.instance }}\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"

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