---
title: "ClickHouse release 26.8"
description: "ClickHouse 26.8 is a long-term support release with 98 new features, 128 performance optimizations, and 556 bug fixes. It adds background queries, PostgreSQL-style regular-expression operators, array subscripting with multiple indices, expanded Parquet and data-lake integrations, and improvements for GROUP BY and joins. Background queries return immediately while continuing after client disconnection, with progress exposed through system.processes and completion details recorded in system.query_log; the example exports 243,619,704 rows to Parquet. Performance work includes dictionary-filter pushdown for Parquet, adaptive parallel GROUP BY processing, smaller hash-table cells for single-string keys, parallel merge joins, IEJoin for two-inequality conditions, and a cost-based optimizer for distributed plans. The PostgreSQL wire protocol supports psql commands such as \\d, \\dt, and \\dv while the release adds text tokenizers."
---

# ClickHouse release 26.8

[Clickhouse](https://yomu.fyi/company/clickhouse) · Sep 10, 2026

**Type:** Announcement

## Summary

ClickHouse 26.8 is a long-term support release with 98 new features, 128 performance optimizations, and 556 bug fixes. It adds background queries, PostgreSQL-style regular-expression operators, array subscripting with multiple indices, expanded Parquet and data-lake integrations, and improvements for GROUP BY and joins. Background queries return immediately while continuing after client disconnection, with progress exposed through system.processes and completion details recorded in system.query\_log; the example exports 243,619,704 rows to Parquet. Performance work includes dictionary-filter pushdown for Parquet, adaptive parallel GROUP BY processing, smaller hash-table cells for single-string keys, parallel merge joins, IEJoin for two-inequality conditions, and a cost-based optimizer for distributed plans. The PostgreSQL wire protocol supports psql commands such as \\d, \\dt, and \\dv while the release adds text tokenizers.

## Context

The release is presented as ClickHouse’s next monthly update and a long-term support release, addressing long-running query execution, SQL and PostgreSQL compatibility, data-lake integration, Parquet processing, aggregation performance, and joins.

## Approach / What changed

The release introduces background execution controlled by run\_query\_in\_background, new SQL operators and array indexing behavior, Parquet dictionary and spatial pruning, adaptive and parallel GROUP BY algorithms, improved join algorithms, and cost-based optimization for distributed query plans.

## Takeaways

- Setting run\_query\_in\_background to 1 lets a query return immediately and continue after the client disconnects; system.processes exposes progress and system.query\_log records completion details.
- Parquet dictionary-filter pushdown skips row groups whose dictionaries cannot match a filter; the setting defaults to a 1 MiB dictionary-page limit and can be disabled with value 0.
- Small-table column statistics are now built on INSERT by default, producing a reported 29% improvement across all TPC-H benchmarks.

**Tags:** [ClickHouse](https://yomu.fyi/topic/clickhouse), [Parquet](https://yomu.fyi/topic/parquet), [SQL](https://yomu.fyi/topic/sql)

- Source: [Clickhouse](https://clickhouse.com/blog/clickhouse-release-26-08)
- Source URL: https://clickhouse.com/blog/clickhouse-release-26-08
- Ingested by Yomu: 2026-09-11T16:02:39.575Z

[Read original post](https://clickhouse.com/blog/clickhouse-release-26-08)