Skip to main content

Aiven for ClickHouse® metrics exposed in Grafana®

Browse through metrics that are available via Grafana® for Aiven for ClickHouse® services.

Current counts​

The following metrics are displayed on the monitoring dashboard as counts reflecting the current status:

  • Databases: Number of databases
  • Tables: Number of tables
  • Parts: Total number of MergeTree table parts
  • Rows total: Total number of rows
  • Running Queries: Total number of queries currently executed
  • Running Merges: Number of merges currently executed in the background
  • Parts Merged: Number of times data parts of ReplicatedMergeTree tables were successfully merged
  • Readonly Tables: Number of replicated tables that are currently in the read-only state due to re-initialization after ZooKeeper session loss or due to startup without ZooKeeper configured

Charts​

The following metrics are displayed on the monitoring dashboard as charts reflecting data changes over time:

Connections​

  • Number of connections to the TCP server (clients with native interface), also included server-server distributed query connections
  • Number of connections to the HTTP server
  • Number of connections from other replicas to fetch parts

Queries​

  • Number of executed SELECT queries (includes internal/monitoring queries)
  • Number of executed INSERT queries
  • Number of failed queries

Delayed Queries​

  • Number of INSERT queries that are throttled due to high number of active data parts for partition in a MergeTree table
  • Number of queries that are stopped and waiting due to 'priority' setting

Replicated Part Fetches​

  • Number of data parts being checked for consistency
  • Number of data parts being fetched from replica Each fetch consumes disk IO and inter-server network IO.

Miscellaneous​

  • Running Merges Merge operations reduce the number of parts and improve SELECT performance. Each merge consumes disk IO (read and write). A new part will be merged approximately 15 min after being inserted.
  • Inserted Rows: Number of rows INSERTed to all tables
  • Inserted Bytes: Number of bytes (uncompressed) INSERTed to all tables
  • Merged Rows: Rows read for background merges (before merge)
  • Merged: Data Read: Uncompressed bytes that were read for background merges
  • Compressed Data Read: Number of bytes before decompression read from compressed sources
  • Rows Delta: Difference in number of rows between nodes
  • Parts: Total number of MergeTree table parts. Each INSERT creates a new part.
  • Replicated Part Merged