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Monitor a LakeTS deployment

LakeTS exposes operational state through SQL functions, so ChronoTable, RollUp, and query-workload visibility comes from inside Lakebase without an external metrics service. A Prometheus-compatible endpoint is also available for scraping from outside.

Operational metrics​

SELECT * FROM lakets.lakets_metrics();

Returns chunk counts, row counts per ChronoTable, RollUp lag, tiering backlog (lakets_tiering_pending_chunks, lakets_tiering_tiered_chunks_total, lakets_tiering_caught_up), and last refresh times.

Chunk health​

SELECT * FROM lakets.chunk_health();

Per-ChronoTable: count of active / tiered / dropped chunks, oldest chunk age, newest chunk age. Use this to confirm tiering and retention are running.

Diagnose stalled tiering​

When chunks past the policy age have not been flagged or dropped, show_tiering_status reports where the durability gate is held up:

SELECT * FROM lakets.show_tiering_status('metrics');

Read the result top-down:

  • cdf_status — NONE means sync was never enabled (lakets.enable_sync('metrics') was never called); SKIPPED means the shadow table isn't streaming (often a missing REPLICA IDENTITY FULL); STREAMING means CDF is healthy.
  • cdf_lag_bytes — how far CDF must still flush before the durability gate passes. While this is non-zero for pending chunks, the gate keeps deferring.
  • caught_up — TRUE when the gate passes for every pending chunk. Once true, the next Tiering Job run flags those chunks tiered; retention then drops their partitions at drop_after.

Tiering is fail-closed: if CDF is NONE, SKIPPED, or still lagging, chunks are neither flagged nor dropped until the data is provably durable in Unity Catalog. See Lakebase CDF Setup to bring sync up.

Top queries​

SELECT * FROM lakets.query_stats(10);

Top N queries by total time, mean time, calls — useful for identifying which dashboard panels are hot enough to deserve a RollUp.

Prometheus-compatible endpoint​

The monitoring/ module exposes a /metrics endpoint in Prometheus exposition format for scraping from outside Lakebase. See the Monitoring reference for the full list of metrics functions.