Blog

• ClickHouse Replica Is in Readonly Mode: Read the Keeper Session First

  August 28, 2026

  A ReplicatedMergeTree table goes read-only when the replica loses its Keeper session. Four queries tell you whether Keeper is down, whether the session is flapping, and whether SYSTEM RESTART REPLICA will fix it.

• ClickHouse System Tables for Monitoring: The Complete Field Reference

  August 22, 2026

  The seven system tables that carry almost all of the on-call signal in ClickHouse: which columns to read, what the values mean, what each one looks like when it goes wrong, and the order to read them in during an incident.

• ClickHouse Merge Is Stuck: Five Checks Before You Restart the Server

  August 11, 2026

  A merge that stops moving is usually one of five things: a saturated pool, disk pressure, a blocking mutation, a part that no replica has, or merges someone switched off. Here is how to tell which, from SQL you can run in seconds.

• A DataGrip Alternative for ClickHouse on Mobile

  July 11, 2026

  If you live in DataGrip at your desk, this covers what changes on a phone during an incident, and what a ClickHouse-native mobile tool handles that a desktop IDE can't.

• A TablePlus Alternative for ClickHouse on iPhone

  July 10, 2026

  Generic database clients are great on the desktop. On a phone during an incident you want a ClickHouse-native monitoring tool. An honest comparison.

• ClickHouse Too Many Parts: What the Signal Means on Call

  July 9, 2026

  Why the 'too many parts' condition happens in ClickHouse, how to read it from your phone, what to do about it, and why OPTIMIZE FINAL is a dangerous reflex.

• Why Is My ClickHouse Replica Lagging?

  July 8, 2026

  A field checklist for diagnosing ClickHouse replica lag from replication_queue, Keeper, is_readonly, and the network, and triaging it from your phone.

• Kill a Runaway ClickHouse Query from Your Phone

  July 7, 2026

  How to find a stuck query in system.processes, judge whether to kill it, and run KILL QUERY safely from your iPhone, plus what kill does and does not do.

• How to Monitor ClickHouse from Your iPhone

  July 6, 2026

  Which system tables matter on call, what to watch during an incident, and how to keep an eye on a ClickHouse cluster from a phone without a laptop.

• How to Reach Prod ClickHouse Through an SSH Tunnel from iOS

  July 5, 2026

  Connect to a production ClickHouse cluster behind a bastion from your iPhone, securely: key or password auth, host-key verification, and nothing proxied through anyone.