clickhouse
https://github.com/yandex/clickhouse
C++
ClickHouse is a free analytic DBMS for big data.
Triage Issues!
When you volunteer to triage issues, you'll receive an email each day with a link to an open issue that needs help in this project. You'll also receive instructions on how to triage issues.
Triage Docs!
Receive a documented method or class from your favorite GitHub repos in your inbox every day. If you're really pro, receive undocumented methods or classes and supercharge your commit history.
C++ not yet supported66 Subscribers
Add a CodeTriage badge to clickhouse
Help out
- Issues
- Speed up the `-Distinct` combinator for integer keys
- Partition pruning skips matching parts for a `Tuple` key with a `FixedString` element
- Use the SIMD IPv4 parser in `toIPv4` from `String`
- Add ULID binary conversion functions
- Group fsync of inserted parts with `fsync_after_insert`
- A WHERE that filters nothing raises GROUP BY peak memory up to 2x: the query condition cache rounds blocks to 65536 rows, PODArray doubles them to a power of two, and the adaptive aggregator keeps them
- Rewrite count(col) to count() when the column cannot be NULL, enabling the inline-count aggregation fast path
- uniqExact state preallocates 16 cells (~250 bytes) per group; dominates high-cardinality GROUP BY with tiny groups (ClickBench Q14 ~25%)
- Iceberg commit retries a failed metadata write as a lost race: `OPTIMIZE TABLE ... MANIFEST` ends in `LOGICAL_ERROR` after 100 attempts
- Fix `JSON_VALUE`, `JSON_QUERY` and `JSON_EXISTS` taking a JSONPath array index modulo 2^32
- Docs
- C++ not yet supported