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ClickHouse upgrades break working setups

Outages and change6 posts from 5 people4d active+66 posts in the last 7 days, 0 the 7 days before (new)

Posts per day

Posts per day6 posts, Sep 21 to Sep 27

The posts behind it

6, newest first
PostDate
hasAny over Array(String) compares every element with every constant needle: a needle hash set cuts a 32-needle hasAny from 5.4 s to 0.52 s### Describe the situation `hasAny(arr, [constants])` over an `Array(String)` column compares every element with every needle through a virtual `IColumn::compareAt`, because `sliceHasImplAnyAll` is specialised only for numeric arrays. A row without a match therefore costs...ClickHouse/ClickHousesnelheidaiSep 252 days ago
Text index prunes matching rows: decline keys on needle padding, not value's### Describe what's wrong - `WHERE s = toFixedString(...)` on a `String` column silently prunes rows whose value equals the needle plus trailing zero bytes. - Triggered by `text(tokenizer = array)` or `text(tokenizer = splitByString([sep]))` indexes when `use_skip_indexes = 1`,...ClickHouse/ClickHouseclickgapaiSep 234 days ago
Reuse checksum-matching detached parts when bootstrapping a fresh replica### Use case When creating a fresh ReplicatedMergeTree replica, we want to seed it from an object-storage backup instead of transferring the entire dataset from peers. Backup parts can be restored into the table’s detached/ directory. Attaching them normally may allocate new...ClickHouse/ClickHousepatelsmit32123Sep 225 days ago
BACKUP/RESTORE ... TABLE db.t AS t loses the rename through parseQueryToJSON / formatQueryFromJSON (RESTORE target silently changes database)`BACKUP`/`RESTORE ... TABLE db.t AS t` loses the rename through `parseQueryToJSON` / `formatQueryFromJSON`. For `RESTORE` this changes what the query does: the `AS` clause is the destination, so `RESTORE TABLE d.t AS t FROM ...` (restore into the current database) silently...ClickHouse/ClickHouseqoegaSep 225 days ago
ALTER NAMED COLLECTION DELETE lacks dependency check, breaks table reload...engine definition needs ` ` from `nc`. - The table keeps working after the ALTER but fails to load on next ATTACH or server restart with a required-keys error. - `DROP NAMED COLLECTION` correctly refuses this same case with NAMED_COLLECTION_IS_USED, but ALTER DELETE does not. -...ClickHouse/ClickHouseclickgapaiSep 225 days ago
Implement compact snapshot files for `plain_rewritable` disks to speed up initialization and updates.### Company or project name ClickHouse ### Describe the situation Initialization of a `plain_rewritable` disks can take a lot of time, as it has to list the metadata directory, read all `prefix.path` files, and list all the related directories. It can be tens of thousands of S3...ClickHouse/ClickHousealexey-milovidovSep 216 days ago

Companies and products named

Company or productPosts naming it
ClickHouse6
GitHub2
Text1
About this problem

Evidence

6 posts from 5 people in 1 place, about 6 a week over 5 days. Mostly on ClickHouse/ClickHouse. Tools named alongside: GitHub, Text.

Frustration Frustration 0 of 3· Seen on GitHub issues

How it was grouped

Posts that state a pain and match the "breaking-changes" rule about ClickHouse. First post Sep 21, 2026, latest Sep 25, 2026. Corroborated: 3 or more posts from 2 or more people or places. Method

History

  • 2026-09-27 Added: ClickHouse upgrades break working setups (6 posts)

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