v.25.8Improvement

All the allocations done

All the allocations done by external libraries are now visible to ClickHouse's memory tracker and accounted properly. This may result in "increased" reported memory usage for certain queries or failures with MEMORY_LIMIT_EXCEEDED. #84082 (Nikita Mikhaylov).
All memory allocations performed by external libraries are now tracked and accounted for by ClickHouse's memory tracker.

Why it matters

Previously, memory used by external libraries was not visible to ClickHouse's memory tracker, which could lead to underreported memory usage and unexpected resource exhaustion. This feature ensures accurate memory tracking across all allocations, helping prevent out-of-memory errors and providing more reliable resource management.

How to use it

This feature is enabled by default as part of the ClickHouse update. Users may observe increased reported memory usage or receive MEMORY_LIMIT_EXCEEDED errors in queries due to now-accounted external library allocations.