---
sidebar_position: 1
sidebar_label: 2025
---

# 2025 Changelog

### ClickHouse release v25.6.4.12-stable (c3c91c0239e) FIXME as compared to v25.6.3.116-stable (3c68d19c3b3)

#### Improvement
* Backported in [#83635](https://github.com/ClickHouse/ClickHouse/issues/83635): When `distributed_ddl_output_mode='*_only_active'`, don't wait for new or recovered replicas that have replication lag bigger than `max_replication_lag_to_enqueue`. This should help to avoid `DDL task is not finished on some hosts` when a new replica becomes active after finishing initialization or recovery, but it accumulated huge replication log while initializing. Also, implement `SYSTEM SYNC DATABASE REPLICA STRICT` query that waits for replication log to become below `max_replication_lag_to_enqueue`. [#83302](https://github.com/ClickHouse/ClickHouse/pull/83302) ([Alexander Tokmakov](https://github.com/tavplubix)).

#### Bug Fix (user-visible misbehavior in an official stable release)
* Backported in [#83556](https://github.com/ClickHouse/ClickHouse/issues/83556): Disable bounds-based file pruning for iceberg array element and iceberg map values, including all their nested subfields. [#83520](https://github.com/ClickHouse/ClickHouse/pull/83520) ([Daniil Ivanik](https://github.com/divanik)).
* Backported in [#83674](https://github.com/ClickHouse/ClickHouse/issues/83674): Fix incorrect memory around max_untracked_memory. [#83607](https://github.com/ClickHouse/ClickHouse/pull/83607) ([Azat Khuzhin](https://github.com/azat)).
* Backported in [#83663](https://github.com/ClickHouse/ClickHouse/issues/83663): INSERT SELECT with UNION ALL could lead to a null pointer dereference in a corner case. This closes [#83618](https://github.com/ClickHouse/ClickHouse/issues/83618). [#83643](https://github.com/ClickHouse/ClickHouse/pull/83643) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Backported in [#83745](https://github.com/ClickHouse/ClickHouse/issues/83745): Fix endless loop in estimateCompressionRatio() with block_size_bytes=0. [#83704](https://github.com/ClickHouse/ClickHouse/pull/83704) ([Azat Khuzhin](https://github.com/azat)).

