---
title: "ClickHouse Release 26.5"
description: "ClickHouse 26.5 is a monthly release containing 38 new features, 51 performance optimizations, and 224 bug fixes. It reports a record number of performance optimizations and introduces a filesystem table function for running SQL against a local file system. Its main query-planning examples push ORDER BY … LIMIT through eligible LEFT or RIGHT JOINs when the sort key depends only on the preserved side, allowing ClickHouse to limit rows before joining. In a TPC-H benchmark at scale factor 100, enabling this optimization reduced fastest runtime from 1.878 seconds to 0.092 seconds, peak memory from 1.88 GiB to 10.98 MiB, and data read by 1.5×. Additional changes include a GROUP BY … LIMIT shortcut for eligible unordered queries, an experimental in-browser clickhouse-client, and per-subquery query-cache controls."
---

# ClickHouse Release 26.5

[Clickhouse](https://yomu.fyi/company/clickhouse) · Jun 1, 2026

**Type:** Announcement

## Summary

ClickHouse 26.5 is a monthly release containing 38 new features, 51 performance optimizations, and 224 bug fixes. It reports a record number of performance optimizations and introduces a filesystem table function for running SQL against a local file system. Its main query-planning examples push ORDER BY … LIMIT through eligible LEFT or RIGHT JOINs when the sort key depends only on the preserved side, allowing ClickHouse to limit rows before joining. In a TPC-H benchmark at scale factor 100, enabling this optimization reduced fastest runtime from 1.878 seconds to 0.092 seconds, peak memory from 1.88 GiB to 10.98 MiB, and data read by 1.5×. Additional changes include a GROUP BY … LIMIT shortcut for eligible unordered queries, an experimental in-browser clickhouse-client, and per-subquery query-cache controls.

## Context

The release is presented as the next monthly ClickHouse release, with a record number of performance optimizations alongside new features and bug fixes.

## Approach / What changed

ClickHouse adds query-plan optimizations that move eligible ORDER BY … LIMIT work before joins and avoid building unnecessary groups for certain unordered GROUP BY … LIMIT queries. The release also adds a filesystem table function, an experimental in-browser clickhouse-client, and settings for controlling query-cache use and propagation at the subquery level.

## Takeaways

- ORDER BY … LIMIT pushdown is enabled by the query\_plan\_top\_k\_through\_join setting and applies to LEFT or RIGHT JOIN queries when the sort key uses only columns from the preserved side.
- In the stated TPC-H scale-factor-100 benchmark, the join pushdown reduced fastest runtime 20.4×, lowered peak memory usage by about 175×, and read 1.5× less data.
- The experimental Web Terminal is enabled with allow\_experimental\_webterminal, while query caching can be enabled or disabled for individual subqueries or propagated into all subqueries.

**Tags:** [Caching](https://yomu.fyi/topic/caching), [Developer Experience](https://yomu.fyi/topic/developer-experience), [Performance](https://yomu.fyi/topic/performance)

- Source: [Clickhouse](https://clickhouse.com/blog/clickhouse-release-26-05)
- Source URL: https://clickhouse.com/blog/clickhouse-release-26-05
- Ingested by Yomu: 2026-08-29T00:01:02.159Z

[Read original post](https://clickhouse.com/blog/clickhouse-release-26-05)