ClickhouseInterserverConnectionIssues

ClickhouseInterserverConnectionIssues #

An increase in interserver connections may indicate replication or distributed query handling issues.

Alert Rule
alert: ClickhouseInterserverConnectionIssues
annotations:
  description: |-
    An increase in interserver connections may indicate replication or distributed query handling issues.
      VALUE = {{ $value }}
      LABELS = {{ $labels }}    
  runbook: https://srerun.github.io/prometheus-alerts/runbooks/clickhouse-internal/clickhouseinterserverconnectionissues/
  summary: ClickHouse Interserver Connection Issues (instance {{ $labels.instance
    }})
expr: increase(ClickHouseMetrics_InterserverConnection[5m]) > 0
for: 1m
labels:
  severity: warning

Meaning #

The ClickhouseInterserverConnectionIssues alert is triggered when there is an increase in interserver connections in a ClickHouse cluster. This can be an indication of replication or distributed query handling issues.

Impact #

This alert can have a significant impact on the performance and reliability of the ClickHouse cluster. Unaddressed, it can lead to:

  • Increased latency and timeouts in query execution
  • Reduced cluster availability and increased risk of downtime
  • Inconsistent data replication and potential data loss
  • Decreased overall system reliability and stability

Diagnosis #

To diagnose the root cause of the ClickhouseInterserverConnectionIssues alert, follow these steps:

  1. Check the ClickHouse cluster logs for errors related to interserver connections, replication, and distributed query handling.
  2. Verify that the ClickHouse cluster is properly configured and that all nodes are reachable.
  3. Check the network connectivity and latency between nodes in the cluster.
  4. Review the ClickHouse metrics, such as ClickHouseMetrics_InterserverConnection, to identify patterns or trends that may indicate the root cause of the issue.
  5. Consult with the ClickHouse documentation and troubleshooting guides for further assistance.

Mitigation #

To mitigate the ClickhouseInterserverConnectionIssues alert, follow these steps:

  1. Investigate and resolve any network connectivity issues between nodes in the cluster.
  2. Check the ClickHouse configuration and ensure that it is properly set up for replication and distributed query handling.
  3. Verify that all nodes in the cluster are running the same version of ClickHouse and that there are no compatibility issues.
  4. Consider adjusting the ClickHouse configuration settings, such as the interserver_http_send_timeout or interserver_http_receive_timeout, to optimize interserver communication.
  5. If the issue persists, consider upgrading or scaling the ClickHouse cluster to improve performance and reliability.

Remember to refer to the ClickHouse documentation and troubleshooting guides for more detailed information on diagnosing and mitigating interserver connection issues.

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