v.18.12Improvement

Fixed Performance Issue with Large Error-Inducing Query Streams

Official CH changelog text
Fixed a performance problem in the case of a large stream of queries that result in an error (the _dl_addr function is visible in perf top, but the server isn’t using much CPU). #2938
Fixed a performance issue where a large stream of error-producing queries caused the server to show high _dl_addr overhead in profiling but low actual CPU usage.

Why it matters

This fix addresses inefficient CPU usage observed when processing many failing queries, improving server responsiveness and resource utilization under error-heavy query loads.

How to use it

The fix is applied internally in ClickHouse; users benefit from this improvement by upgrading to the version containing this change without any special configuration.

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