Issues

• Remove the possibility to declare STATISTICS explicitly per column

  comp-mergetreemake it worse
  ClickHouse/ClickHouse#127785 · Filter by author alexey-milovidov opened on Oct 25, 2026

• Partition pruning drops the NULL partition for not(const < (nullable_partition_key IS NULL)) — silent wrong results on default config

  ai_p2comp-mergetreefuzzsqlancer
  ClickHouse/ClickHouse#127755 · Filter by author qoega opened on Oct 24, 2026
  1

• bloom_filter skip index false-negative on has(Array(String), <non-const FixedString(N) needle>) with N>stored len — silent data loss on default use_skip_indexes=1

  comp-skip-indexfuzzsqlancer
  ClickHouse/ClickHouse#127754 · Filter by author qoega opened on Oct 24, 2026
  1

• VirtualRowTransform throws NOT_IMPLEMENTED on lambda column (Code 48)

  ai_p3comp-query-optimizer
  ClickHouse/ClickHouse#127748 · Filter by author clickgapai opened on Oct 24, 2026

• SIGSEGV in MatchImpl::vectorConstant on LowCardinality column pruned by query_plan_remove_unused_columns + PREWHERE partial-header eval

  comp-regular-functionfuzz
  ClickHouse/ClickHouse#127747 · Filter by author qoega opened on Oct 24, 2026
  3

• UTC-bounded DateTime64 window mishandles late 9999-12-31 values behind UTC

  ai_p2comp-datetime
  ClickHouse/ClickHouse#127742 · Filter by author clickgapai opened on Oct 24, 2026
  1

• Filesystem cache background download bypasses workload IO scheduling

  ai_p2comp-filesystem-cachecomp-scheduler
  ClickHouse/ClickHouse#127738 · Filter by author serxa opened on Oct 24, 2026
  1

  

• Wide count narrowed before the limit check in leftPad, arrayResize & co

  ai_p2comp-regular-function
  ClickHouse/ClickHouse#127737 · Filter by author clickgapai opened on Oct 24, 2026

• MongoDB pushdown treats Bool as a number: b = 1 sends {$eq: 1}, 0 rows

  ai_p1comp-foreign-db
  ClickHouse/ClickHouse#127736 · Filter by author clickgapai opened on Oct 24, 2026

• MySQLDump format rejects dumps starting with CREATE DATABASE

  ai_p3comp-formats
  ClickHouse/ClickHouse#127735 · Filter by author clickgapai opened on Oct 24, 2026

• MySQLDump format misparses CREATE TABLE IF NOT EXISTS table name as IF

  ai_p3comp-formats
  ClickHouse/ClickHouse#127734 · Filter by author clickgapai opened on Oct 24, 2026

• MV with unreachable TO table breaks system.tables and ATTACH

  ai_p2comp-materialized-view
  ClickHouse/ClickHouse#127733 · Filter by author clickgapai opened on Oct 24, 2026

• BigQuery GEOGRAPHY writes round coordinates to 6 significant digits

  ai_p1comp-foreign-db
  ClickHouse/ClickHouse#127730 · Filter by author clickgapai opened on Oct 24, 2026

• Iceberg cluster reads fail with PATH_ACCESS_DENIED on symlinked metadata dir

  ai_p3comp-datalake
  ClickHouse/ClickHouse#127727 · Filter by author clickgapai opened on Oct 24, 2026

• RETURNING read limit in break mode silently truncates the INSERT

  ai_p2comp-query-execution
  ClickHouse/ClickHouse#127724 · Filter by author clickgapai opened on Oct 24, 2026

• INSERT ... RETURNING with constant-false JOIN succeeds but writes no rows

  ai_p1comp-query-optimizer
  ClickHouse/ClickHouse#127723 · Filter by author clickgapai opened on Oct 24, 2026

• input inside RETURNING gives LOGICAL_ERROR 'Input initializer is not set'

  ai_p1comp-query-execution
  ClickHouse/ClickHouse#127722 · Filter by author clickgapai opened on Oct 24, 2026

• file() TopK query condition cache key omits use_hive_partitioning

  ai_p2comp-query-execution
  ClickHouse/ClickHouse#127721 · Filter by author clickgapai opened on Oct 24, 2026

• Parquet read of missing DEFAULT column aborts server

  ai_p1comp-parquet-reader-v3
  ClickHouse/ClickHouse#127720 · Filter by author clickgapai opened on Oct 24, 2026

• Bucket-split cluster read drops Iceberg deletes, now reachable for tables

  ai_p1comp-datalake
  ClickHouse/ClickHouse#127719 · Filter by author clickgapai opened on Oct 24, 2026

• Truncated .zst/.lz4 input reads back as complete file, no error

  ai_p2comp-codecs
  ClickHouse/ClickHouse#127714 · Filter by author clickgapai opened on Oct 24, 2026

• Empty INSERT into .lz4 file corrupts later reads (LZ4_DECODER_FAILED)

  ai_p3comp-codecs
  ClickHouse/ClickHouse#127713 · Filter by author clickgapai opened on Oct 24, 2026

• Reading valid Arrow structs with bad field names pollutes system.errors

  ai_p3comp-datatype-wrapper
  ClickHouse/ClickHouse#127711 · Filter by author clickgapai opened on Oct 24, 2026

• ORC US/* writer zone + matching America/* reader zone: use-after-free

  ai_p1comp-external-dependencies
  ClickHouse/ClickHouse#127710 · Filter by author clickgapai opened on Oct 24, 2026

• system.stack_trace query stops at first thread_id block with no match

  ai_p3comp-system-table
  ClickHouse/ClickHouse#127704 · Filter by author clickgapai opened on Oct 24, 2026