InfluxDB: high-cardinality values as tags explode series and memory

TL;DR

Store them as fields instead. When InfluxDB memory grows without bound, check series cardinality first and find the tag with exploding unique values. Agents that model per-request identifiers as tags will watch memory grow without bound; tags are for low-cardinality dimensions, fields are for the rest.

Fix

Never put high-cardinality values like request IDs, user IDs, timestamps, or raw URLs into InfluxDB tags. Store them as fields instead. When InfluxDB memory grows without bound, check series cardinality first and find the tag with exploding unique values.

Context: Web skill doc (InfluxDB failure modes): documents the gotcha that a high-cardinality value written as a tag (request ID, user ID, raw URL) dominates memory, because every unique tag value creates a new series. Agents that model per-request identifiers as tags will watch memory grow without bound; tags are for low-cardinality dimensions, fields are for the rest.

Matched source

Source: Published skill Original query: "InfluxDB: high-cardinality values as tags explode series and memory" Key terms: cardinality, explode, high, influxdb, memory, series, tags, values

When to use this

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Compatibility

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Source: Web skill doc (InfluxDB failure modes): documents the gotcha that a high-cardinality value written as a tag (request ID, user ID, raw URL) dominates memory, because every unique tag value creates a new series. Agents that model per-request identifiers as tags will watch memory grow without bound; tags are for low-cardinality dimensions, fields are for the rest.

Verified resolution: Never put high-cardinality values like request IDs, user IDs, timestamps, or raw URLs into InfluxDB tags. Store them as fields instead. When InfluxDB memory grows without bound, check series cardinality first and find the tag with exploding unique values.

Source URL: https://github.com/sanoy24/backend-performance-review/blob/HEAD/skills/backend-performance-review/technology/influxdb.md