Problemsby IbisTrouble with ClickHouse slower
Databases3 posts from 1 person3d active+00 posts in the last 7 days, 1 the 7 days before (fading)Unverified
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The posts behind it
3, newest first`timeSeries*ToGrid` 14-24x slower on series with a mid-range gap### Describe what's wrong - Aggregating a time series with a gap in the middle of its range is 3-24x slower, though results stay correct. - Trigger: a 7-day 60s grid over 200 series, each with 6200 populated buckets and a gap mid-range. - Expected the same ~0.06s as a contiguous...ClickHouse/ClickHouse · clickgapaiOpen ↗Selective `filter` kernel 1.3x slower (`IPv4` 2x) when hint is under 64### Describe what's wrong - `ColumnVector ::filter` runs a per-block tail branch when `result_size_hint` is below 64 rows. - Trigger: filtering with an exact hint under 64, e.g. `FilterTransform` or Memory-engine prewhere on 1/2/4/8-byte columns. - Expected equal cost for...ClickHouse/ClickHouse · clickgapaiOpen ↗Window functions 5-11% slower: Partition::advance scans row by row### Describe what's wrong - Streaming window queries got measurably slower in CI perf tests. - Triggered by any window function query, e.g. `ntile(4) OVER (ORDER BY number)` or `count() OVER (ROWS UNBOUNDED PRECEDING)`. - Expected O(1) or galloping-search cost per block; actual...ClickHouse/ClickHouse · clickgapai2 repliesOpen ↗
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About this problem
Evidence
3 posts from 1 person in 1 place, about 2 a week over 12 days. Mostly on ClickHouse/ClickHouse. Tools named alongside: GitHub.
Frustration Frustration 0 of 3· Seen on GitHub issues
How it was grouped
Posts about ClickHouse with no known issue, sharing the word "slower". First post Oct 3, 2026, latest Oct 14, 2026. Unverified: fewer than 3 posts, or one person or place only. Method
Other ClickHouse problems
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History
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Trouble with ClickHouse slower (3 posts)