# ClickHouse 25.6 summer bonus: CoalescingMergeTree table engine

DevFeed: [ClickHouse 25.6 summer bonus: CoalescingMergeTree table engine](<https://devfeed.tech/articles/clickhouse-25-6-summer-bonus-coalescingmergetree-table-engine-5054.md>)

Original publisher: [Read original article](<https://clickhouse.com/blog/clickhouse-25-6-coalescingmergetree>)

Author: ClickHouse

Published: 2025-07-14T07:27:24Z

Content type: article

Language: en

Sources: [ClickHouse Blog](<https://devfeed.tech/sources/clickhouse-blog.md>)

Topics: [clickhouse](<https://devfeed.tech/topics/clickhouse.md>), [Internet of things](<https://devfeed.tech/topics/iot.md>), [data](<https://devfeed.tech/topics/data.md>), [Databases](<https://devfeed.tech/topics/databases.md>)

Tags: [clickhouse](<https://devfeed.tech/tags/clickhouse.md>), [configuration](<https://devfeed.tech/tags/configuration.md>), [data](<https://devfeed.tech/tags/data.md>), [firmware](<https://devfeed.tech/tags/firmware.md>), [gps](<https://devfeed.tech/tags/gps.md>), [iot](<https://devfeed.tech/tags/iot.md>), [sensors](<https://devfeed.tech/tags/sensors.md>), [speed](<https://devfeed.tech/tags/speed.md>), [telemetry](<https://devfeed.tech/tags/telemetry.md>)

## AI overview

This article introduces CoalescingMergeTree, a new ClickHouse 25.6 table engine that consolidates sparse, append-only updates on disk. It is designed for fragmented data such as IoT device state, configuration snapshots, and telemetry, reducing row counts while preserving information.

## Source excerpt

CoalescingMergeTree is a new table engine in ClickHouse 25.6 that consolidates sparse, append-only updates on disk. Ideal for IoT, ETL, and enrichment pipelines where data arrives in fragments over time.