chmonitor v0.3.8 — Find what nobody reads

chmonitor v0.3.8 ships 34 new features, 96 fixes, and 6 performance changes since v0.3.7. The advisor finds data nobody reads, detached parts get a careful triage, storage shows which queries hit a table, and alert reminders are quieter.

chmonitor v0.3.8 launch video title card with 34 features, 96 fixes and 6 performance changes

What’s new in v0.3.8

Unread dataUnread tables, unread columns, and unused projections, as an insight and an agent tool.
Detached parts triageA read-only view and agent tool that sorts detached parts into review classes.
Hot query shapesFor one table: which query shapes hit it, how often, and how many bytes they read.
New insightsRepeated OPTIMIZE, heavy TTL merges, a retention forecast, and codec checks.
Quieter remindersPer-rule cooldown and mute, per-severity repeat, and back-off while a value stays flat.
New alert rulesFailing dictionaries, stuck Distributed queues, near max_concurrent_queries, and disks that fill within 24h.

Find what nobody reads

The advisor now looks at the query log window and reports tables nobody read, columns nobody read, and projections no query used. Each one is an insight on the overview and a storage view of its own, and the agent can ask for the same list with a tool. The advisor also questions codecs that do not match the data, and judges size savings from the measured compression ratio.

Detached parts triage

Detached parts are easy to get wrong: some are still owned by ClickHouse, some are broken, and some look covered but only on one replica. The new detached parts triage view groups them by table and reason, and gives each group a review class.

Isometric figure of a triage bench: a detached part on a carriage is measured against the active part of its partition, then sorted into four review trays

cannot_drop_via_sql — attaching, deleting, or tmp-fetch parts that ClickHouse still owns.
needs_attention — broken, broken-on-start, unexpected, or noquorum parts. Coverage never makes these reviewable.
review_after_coverage_check — ignored, clone, or covered-by-broken parts that sit inside an active part of the same partition, older than 30 days.
review — everything else.

Coverage is checked on this replica only, so no class means “safe to drop”. The agent tool is read-only: it never writes a DROP or ATTACH command, and the owner decides.

Hot query shapes

Open a table in storage and the new hot query shapes view lists the normalized queries that hit it, how often they ran, and how many bytes they read. It is the fastest way to see who depends on a table before you change its sort key or drop it.

Insights

New checks flag work that rewrites data without adding any:

Tables optimized again and again with no new data.
TTL merges that rewrite far more data than is ingested.
A retention forecast for the table that dominates ingest.

Insight enrichment now caps its output tokens, and the sweep can skip the LLM entirely.

Alerts

Repeat reminders know when to stop. You can set a cooldown and mute per rule, a repeat interval per severity, and an opt-in back-off while a value stays flat. Reminders that barely moved are skipped, and the ones that are sent show how long the alert has been open and how much the value changed. Custom targets can be told to alert once until resolved, with one-line digest reminders.

Alerts now carry the deployment name, a dashboard link, and metadata, and Matrix hookshot is a new webhook format. New built-in rules cover dictionaries that fail to load, stuck Distributed send queues, running queries near max_concurrent_queries, and disks that will fill within 24 hours.

Also in this release

The agent gained an explain_clickhouse_symbol docs lookup tool and a settings-audit skill, and PeerDB and Postgres tools turn on when they are configured and reachable.
Large sidebar groups have collapsible subgroups.
Charts pause auto-refresh when they scroll out of view.
In cloud mode, more API routes require sign-in, and many query configs now run on older and newer ClickHouse versions.

Upgrading

Pull the new image or redeploy. The detached parts review alert is opt-in, and repeat-reminder back-off is off until you turn it on.

docker pull ghcr.io/chmonitor/chmonitor:0.3.8

chmonitor v0.3.7 — an agent that reads your page
AI agent docs
GitHub release v0.3.8