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ClickHouse roadmap 2026
#93288 · alexey-milovidov opened on Dec 31, 2025
33
[Easy Money] ClickHouse Bug Bounty Program
#38986 · alexey-milovidov opened on Jul 7, 2022
4
Intern Tasks 2025/2026
#87836 · alexey-milovidov opened on Sep 29, 2025
81

Enum != toFixedString('a', 2) is 1 on 'a' rows: shortcut reads the padding
ClickHouse/ClickHouse#123527 · opened on Oct 2, 2026
KeyCondition still throws for an unknown Enum literal under a key expression
ClickHouse/ClickHouse#123526 · opened on Oct 2, 2026
bloom_filter has-family still converts unknown Enum names and throws
ClickHouse/ClickHouse#123525 · opened on Oct 2, 2026
CANNOT_PACK_ARCHIVE on incremental tar backup: entry sized as full file
ClickHouse/ClickHouse#123515 · opened on Oct 2, 2026
Iceberg: a position-delete file without a pos column gives LOGICAL_ERROR: Could not find column pos in chunk
ClickHouse/ClickHouse#123510 · opened on Oct 2, 2026
1
New DateTime64 -> Date branch ignores date_time_overflow_behavior
ClickHouse/ClickHouse#123496 · opened on Oct 2, 2026
MongoDB $in with a single array literal silently returns no rows
ClickHouse/ClickHouse#123495 · opened on Oct 2, 2026
Iceberg count() too low after Spark compaction: dangling deletes subtracted
ClickHouse/ClickHouse#123494 · opened on Oct 2, 2026
Unqualified dictGet inside SQL UDF used by ALIAS column succeeds on SELECT but fails on DELETE
ClickHouse/ClickHouse#123489 · opened on Oct 2, 2026
1
Parquet dictionary filter: avoid sorting dictionary hashes for a few probes (ClickBench q20 3.9x faster)
ClickHouse/ClickHouse#123487 · opened on Oct 2, 2026
Parquet PREWHERE: decode dictionary-encoded pages with the filter in the decoder (ClickBench q31 -34%, q32 -24%)
ClickHouse/ClickHouse#123483 · opened on Oct 2, 2026
Incremental build fails after a protobuf bump: google-cloud-cpp protos are not regenerated
ClickHouse/ClickHouse#123468 · opened on Oct 2, 2026
LogsQL: unquoted //, /* or -- hides the ;, drops later statements
ClickHouse/ClickHouse#123463 · opened on Oct 2, 2026
LogsQL word filters treat non-Latin-1 chars as word boundaries
ClickHouse/ClickHouse#123462 · opened on Oct 2, 2026
LogsQL negated numeric/IP range filters drop non-numeric or non-IP rows
ClickHouse/ClickHouse#123461 · opened on Oct 2, 2026
A 569-byte ORC file read from object storage aborts the server (libc++ hardening, orc::extractReadRangesForStripe)
ClickHouse/ClickHouse#123450 · opened on Oct 2, 2026
Iceberg DROP PARTITION {p:T} rejected: _CAST form unhandled (pre-existing)
ClickHouse/ClickHouse#123440 · opened on Oct 2, 2026
Transitive LEFT->INNER join conversion breaks direct joins on dictionary lookups
ClickHouse/ClickHouse#123433 · opened on Oct 2, 2026
Exponential planning: collectNullPropagatingInputs revisits shared DAG nodes
ClickHouse/ClickHouse#123432 · opened on Oct 2, 2026
Quantized vector search: vec.quantized plus WHERE fails, column not found
ClickHouse/ClickHouse#123430 · opened on Oct 2, 2026
Vector search with additional_table_filters throws Not found result vec
ClickHouse/ClickHouse#123429 · opened on Oct 2, 2026
Vector index ignores exact_rows_before_limit: count 4, not 64 (pre-existing)
ClickHouse/ClickHouse#123428 · opened on Oct 2, 2026
hasPhrase with Array(String) phrase drops rows on JSON text index
ClickHouse/ClickHouse#123427 · opened on Oct 2, 2026
hasPhrase on FixedString wrongly rejects icu and splitByRegexp tokenizers
ClickHouse/ClickHouse#123426 · opened on Oct 2, 2026
hasPhrase loses rows after a key-range-pruned Phrase cache entry
ClickHouse/ClickHouse#123421 · opened on Oct 2, 2026

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Issues

Issues

`Enum != toFixedString('a', 2)` is 1 on `'a'` rows: shortcut reads the padding

`KeyCondition` still throws for an unknown `Enum` literal under a key expression

`bloom_filter` `has`-family still converts unknown `Enum` names and throws

`CANNOT_PACK_ARCHIVE` on incremental `tar` backup: entry sized as full file

Iceberg: a position-delete file without a `pos` column gives `LOGICAL_ERROR: Could not find column pos in chunk`

New `DateTime64` -> `Date` branch ignores `date_time_overflow_behavior`

MongoDB `$in` with a single array literal silently returns no rows

Iceberg `count()` too low after Spark compaction: dangling deletes subtracted

Unqualified dictGet inside SQL UDF used by ALIAS column succeeds on SELECT but fails on DELETE

Parquet dictionary filter: avoid sorting dictionary hashes for a few probes (ClickBench q20 3.9x faster)

Parquet PREWHERE: decode dictionary-encoded pages with the filter in the decoder (ClickBench q31 -34%, q32 -24%)

Incremental build fails after a protobuf bump: google-cloud-cpp protos are not regenerated

LogsQL: unquoted `//`, `/*` or `--` hides the `;`, drops later statements

LogsQL word filters treat non-Latin-1 chars as word boundaries

LogsQL negated numeric/IP range filters drop non-numeric or non-IP rows

A 569-byte ORC file read from object storage aborts the server (libc++ hardening, `orc::extractReadRangesForStripe`)

Iceberg `DROP PARTITION {p:T}` rejected: `_CAST` form unhandled (pre-existing)

Transitive LEFT->INNER join conversion breaks direct joins on dictionary lookups

Exponential planning: `collectNullPropagatingInputs` revisits shared DAG nodes

Quantized vector search: `vec.quantized` plus `WHERE` fails, column not found

Vector search with `additional_table_filters` throws `Not found result vec`

Vector index ignores `exact_rows_before_limit`: count 4, not 64 (pre-existing)

hasPhrase with Array(String) phrase drops rows on JSON text index

hasPhrase on FixedString wrongly rejects icu and splitByRegexp tokenizers

hasPhrase loses rows after a key-range-pruned Phrase cache entry