Issues

• bug: Cross-block aggregation fails to merge correctly when GROUP BY contains a NULL constant column, producing duplicate rows

  C-bug
  databendlabs/databend#20615 · Filter by author Annie191 opened on Oct 7, 2026

• bug: FUSE table Top-N block pruning incorrectly skips data under ORDER BY ... LIMIT

  C-bug
  databendlabs/databend#20612 · Filter by author Annie191 opened on Oct 6, 2026
  

• bug: TSV loader reads the escaped literal string \\N as NULL (unescapes before matching NULL_DISPLAY)

  C-bug
  databendlabs/databend#20611 · Filter by author hanke580 opened on Oct 4, 2026
  1

  

• bug: ordered aggregates (array_agg / string_agg / listagg ... ORDER BY k) under ROLLUP/CUBE/GROUPING SETS ignore the ORDER BY when k is a rolled-up grouping column

  C-bug
  databendlabs/databend#20610 · Filter by author hanke580 opened on Oct 4, 2026

• bug: VARIANT hash join / GROUP BY / DISTINCT key on JSONB bytes, so values that "=" calls equal (1 vs 1.0) never match

  C-bug
  databendlabs/databend#20609 · Filter by author hanke580 opened on Oct 4, 2026
  

• bug: canceling a table-lock wait leaks a renewed lock revision and blocks writers

  C-bug
  databendlabs/databend#20608 · Filter by author YZL0v3ZZ opened on Oct 3, 2026

• bug: EXPLAIN can block the shared query runtime and stall all queries on a node

  C-bug
  databendlabs/databend#20607 · Filter by author YZL0v3ZZ opened on Oct 3, 2026
  

• bug: canceling a queued query leaks the queue entry and its session

  C-bug
  databendlabs/databend#20606 · Filter by author YZL0v3ZZ opened on Oct 3, 2026

• bug: Python UDF runtime init can stall every query on the node

  C-bug
  databendlabs/databend#20605 · Filter by author YZL0v3ZZ opened on Oct 3, 2026
  

• bug: ARRAY_AGG in multi-table JOIN query incorrectly aggregates NULL array as empty array, causing inconsistent results

  C-bug
  databendlabs/databend#20603 · Filter by author Annie191 opened on Oct 1, 2026

• bug: Multi-table LEFT JOIN split query returns fewer rows than single-table query due to interaction between rank limit and runtime filter

  C-bug
  databendlabs/databend#20601 · Filter by author Annie191 opened on Sep 30, 2026
  

• Iceberg: decimal stored as FIXED_LEN_BYTE_ARRAY fails with "Parquet argument error: EOF: Not enough bytes to decode"

  databendlabs/databend#20588 · Filter by author djouallah opened on Sep 29, 2026
  

• Feature: avoid data rewrite for safe ALTER TABLE MODIFY COLUMN type widening

  C-feature
  databendlabs/databend#20576 · Filter by author dantengsky opened on Sep 24, 2026
  

• bug: Inconsistent query results: multi-table reconstructed query produces duplicate rows due to WHERE predicate pushdown causing RIGHT JOIN anti-join to emit extra rows

  C-bug
  databendlabs/databend#20568 · Filter by author Annie191 opened on Sep 23, 2026
  

• perf: distributed query fragment preparation is sequential and can exceed the leak cleanup timeout

  databendlabs/databend#20563 · Filter by author dqhl76 opened on Sep 23, 2026
  1

  

• bug: CTAS CREATE OR REPLACE leaves old table with NULL dropped_on in tables_with_history

  C-bug
  databendlabs/databend#20562 · Filter by author TCeason opened on Sep 23, 2026
  1

  

• Tracking: optimize window function execution

  databendlabs/databend#20521 · Filter by author dqhl76 opened on Sep 18, 2026
  2

  

• bug: any spilling hash join fails with Internal 1001 "The level N hybrid hash state has been destroyed" once max_hash_join_spill_level >= 2

  C-bug
  databendlabs/databend#20512 · Filter by author hanke580 opened on Sep 16, 2026
  

• bug: NOT IN / <> ALL with a NULL in the subquery returns rows once the mark join spills

  C-bug
  databendlabs/databend#20511 · Filter by author hanke580 opened on Sep 16, 2026
  

• bug: cloned scans lose predicate pushdown during decorrelation

  C-bug
  databendlabs/databend#20509 · Filter by author dqhl76 opened on Sep 16, 2026
  2

  

• bug: ALTER TASK MODIFY AS fails inside a multi-statement task body

  C-bug
  databendlabs/databend#20502 · Filter by author TCeason opened on Sep 15, 2026
  

• InferFilterOptimizer panics with TypedConstantExpr due to ScalarExpr Eq/Hash mismatch

  databendlabs/databend#20494 · Filter by author dantengsky opened on Sep 14, 2026
  

• bug: UnwindError: assertion failed: partition.total > 0 when ORDER BY sorting a BIGINT % FLOAT expression

  C-bug
  databendlabs/databend#20484 · Filter by author Annie191 opened on Sep 13, 2026
  

• bug: Databend query service crashes with IN subquery + correlated scalar subquery + derived table + outer range-correlated MIN

  C-bug
  databendlabs/databend#20477 · Filter by author Annie191 opened on Sep 11, 2026
  1

  

• bug: mixed Decimal scales in virtual columns change Variant string predicates

  databendlabs/databend#20458 · Filter by author zhang2014 opened on Sep 8, 2026