InfluxDB

High Cardinality Drives Query Timeout

critical
latencyUpdated Aug 11, 2025

Queries timeout when filtering or grouping by high-cardinality dimensions. The number of unique tag value combinations explodes query execution cost, especially without proper partitioning.

Sources
Analyze a query plan | InfluxDB Clustered Documentationdocs.influxdata.com
Troubleshoot queries | InfluxDB Clustered Documentationdocs.influxdata.com
Technologies:
InfluxDBThe root cause of this issue originates in InfluxDB
influxdb.query.timeout_count
influxdb.query.execution_duration
influxdb.series.cardinality
How to detect:

Monitor query execution time for timeouts. Check EXPLAIN output for large partition scans. Measure series cardinality using SHOW CARDINALITY or information_schema queries.

Recommended action:

Redesign schema to reduce tag cardinality—move high-cardinality values to fields or use composite partitioning. Apply custom partition templates to isolate high-cardinality dimensions. Add WHERE clauses to limit time ranges and tag combinations in queries.