promql/offset

This check inspects all selectors in queries for offset usage. It will warn if a selector uses an offset that is larger than the Prometheus retention period, since such a query will never return any data.

By default Prometheus keeps 15 days of data, this can be customised by setting time or disk space limits. There are two main ways of configuring retention limits in Prometheus:

• time based - Prometheus will keep last N days of metrics
• disk based - Prometheus will try to use up to N bytes of disk space.

Pint will ignore any disk space limits, since that doesn’t tell us what the effective time retention is. But it will check the value of --storage.tsdb.retention.time flag passed to Prometheus and it will warn if any selector uses an offset larger than Prometheus retention.

For example if Prometheus is running with --storage.tsdb.retention.time=5d and we have a query like foo offset 10d, that query will never return any results because Prometheus doesn’t have any data that old.

This is especially problematic in binary expressions like foo + foo offset 10d where one side returns data but the other doesn’t, which can lead to silently broken queries.

Configuration

This check doesn’t have any configuration options. It is enabled automatically for all configured Prometheus servers.

How to enable it

This check is enabled by default for all configured Prometheus servers.

Example:

prometheus "prod" {
  uri     = "https://prometheus-prod.example.com"
  timeout = "60s"
  include = [
    "rules/prod/.*",
    "rules/common/.*",
  ]
}

prometheus "dev" {
  uri     = "https://prometheus-dev.example.com"
  timeout = "30s"
  include = [
    "rules/dev/.*",
    "rules/common/.*",
  ]
}

How to disable it

You can disable this check globally by adding this config block:

checks {
  disabled = ["promql/offset"]
}

You can also disable it for all rules inside a given file by adding a comment anywhere in that file. Example:

# pint file/disable promql/offset

Or you can disable it per rule by adding a comment to it. Example:

# pint disable promql/offset

If you want to disable only individual instances of this check you can add a more specific comment.

# pint disable promql/offset($prometheus)

Where $prometheus is the name of Prometheus server to disable.

Example:

# pint disable promql/offset(prod)

How to snooze it

You can disable this check until a given time by adding a comment to it. Example:

# pint snooze $TIMESTAMP promql/offset

Where $TIMESTAMP is either RFC3339 formatted or YYYY-MM-DD. Adding this comment will disable promql/offset until $TIMESTAMP, after which the check will be re-enabled.