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Problems.

ClickHouse users keep filing bugs

Databases10 posts from 7 people2d active+1010 posts in the last 7 days, 0 the 7 days before (new)

Posts per day

Posts per day10 posts, Sep 21 to Sep 27

The posts behind it

10, newest first
PostDate
Segmentation fault (STID: 4085-568b)...Failing test history: [cidb](https://play.clickhouse.com/play?user=play&run=1#V0lUSAogICAgOTAgQVMgaW50ZXJ2YWxfZGF5cwpTRUxFQ1QKICAgIHRvU3RhcnRPZkRheShjaGVja19zdGFydF90aW1lKSBBUyBkYXksCiAgICBjb3VudCgpIEFTIGZhaWx1cmVzLAogICAgZ3JvdXBVbmlxQXJyYXkocHVsbF9yZXF1ZXN0X251bWJlcikgQVMgcHJzLA...ClickHouse/ClickHouseAlgunenanoSep 225 days ago
parseQueryToJSON writes a large Float64 literal that formatQueryFromJSON cannot read back (integer overflow in Poco JSON parser)`parseQueryToJSON` writes a large `Float64` literal in positional notation (no `.`, no `e`), and `formatQueryFromJSON` refuses its own writer's output because the JSON parser (Poco) classifies a number without `.`/`e` as an integer and fails when it does not fit 64 bits. ###...ClickHouse/ClickHouseqoegaSep 225 days ago
`minmax` index and Parquet stats prune NaN rows under a negated predicate### Describe what's wrong - A negated float predicate silently loses the `NaN` rows. - On a `MergeTree` table with `INDEX f TYPE minmax`, `SELECT count() FROM t WHERE f != 1.5` returns 0 with the index and 13 without it; `NOT (f Analysis details (evidence, affected locations,...ClickHouse/ClickHouseclickgapaiSep 225 days ago
ARRAY JOIN in an IN subquery splits the GROUP BY key: wrong ROLLUP row### Describe what's wrong - A grouping key containing an `IN` subquery with `ARRAY JOIN` is treated as two different expressions. - Triggered by `GROUP BY ... WITH ROLLUP` (also `CUBE`, `GROUPING SETS`, `TOTALS`) on such a key, with default settings. - The super-aggregate row...ClickHouse/ClickHouseclickgapaiSep 225 days ago
Analyzer: UNKNOWN_IDENTIFIER when alias resolution fails and analyzer_compatibility_join_using_top_level_identifier=1### Company or project name _No response_ ### Describe what's wrong Query fails ### Does it reproduce on the most recent release? Yes ### How to reproduce https://fiddle.clickhouse.com/b2e6cc5e-ca13-4946-be77-0b8ce95a1a4e ### Expected behavior _No response_ ### Error message...ClickHouse/ClickHousenovikdSep 225 days ago
minmax skip index wrongly prunes rows with NaN in Map columns### Describe what's wrong - A minmax index on a `Map(..., Float64)` column drops matching rows instead of returning them. - Triggered by `SELECT count() FROM t WHERE m IN (map('a', nan))` with a minmax index on the Map column. - Expected count is 13 with `use_skip_indexes = 1`,...ClickHouse/ClickHouseclickgapaiSep 225 days ago
Smaller binary via lld ICF of functions with identical exception tables (llvm-project#224929)Since lld commit `21b4f8060ab3`, `--icf=all` refuses to fold any function whose FDE carries an LSDA (exception table), because two functions with identical code may still have different catch blocks. ClickHouse is built with `-ffunction-sections -faddrsig` and linked with...ClickHouse/ClickHousethevar1ableSep 216 days ago
Materialized CTEs are re-analyzed (and re-expanded) at every reference### Company or project name _No response_ ### Describe the situation To get around non-materialized CTEs, we have run some query pipelines as a sequence of temporary tables. Some intermediate results (i.e., temporary tables) are referenced many times within a single query. Now...ClickHouse/ClickHousethomaskSep 216 days ago
RESTORE fails with FUNCTION_ALREADY_EXISTS when a backup contains a UDF whose name is a built-in in the restoring version## Description A backup taken on a version where `CREATE FUNCTION ` was legal cannot be restored on a version that has since registered ` ` as a built-in. Restoring `system.functions` throws and the **entire** RESTORE fails, so none of the tables are restored. ## Repro 1. On...ClickHouse/ClickHouserahulmalik87Sep 216 days ago
LIMIT BY keys_to_keep set compares aliases, so an aliased GROUP BY key is missed### Describe what's wrong - A valid aggregate query is rejected with error code 10 on a stock server with no settings changed - Trigger is a positional `LIMIT 1 BY 1` over `GROUP BY toString(c0)` with `WITH ROLLUP`, `WITH CUBE` or `WITH TOTALS` - Expected the grouped rows, but...ClickHouse/ClickHouseclickgapaiSep 216 days ago

Companies and products named

Company or productPosts naming it
ClickHouse10
GitHub5
Docker1
About this problem

Evidence

10 posts from 7 people in 1 place, about 10 a week over 2 days. Mostly on ClickHouse/ClickHouse. Tools named alongside: GitHub, Docker.

Frustration Frustration 0 of 3· Seen on GitHub issues

How it was grouped

Posts about ClickHouse that state a pain but match no known issue yet. First post Sep 21, 2026, latest Sep 22, 2026. Corroborated: 3 or more posts from 2 or more people or places. Method

History

  • 2026-09-27 Added: ClickHouse users keep filing bugs (10 posts)

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