rocks_spool_compaction_pending

Type: Gauge
Labels: path

Set to 1 when at least one compaction is pending for this rocksdb instance, 0 otherwise.

Info

This metric has labels which means that the system will track the metric for each combination of the possible labels that are active. Certain labels, especially those that correlate with source or destination addresses or domains, can have high cardinality. High cardinality metrics may require some care and attention when provisioning a downstream metrics server.

Since: Version 2026.09.22-a276d4a8

The functionality described in this section requires version 2026.09.22-a276d4a8 of KumoMTA, or a more recent version.

Brief flapping is normal under write load. A value of 1 that persists alongside rocks_spool_num_running_compactions == 0 is suspicious and suggests the compaction worker is not making progress.