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


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


  • 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


  • 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.


  • 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