Company or project name

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Describe the unexpected behaviour

Hi ClickHouse team,

We've observed an issue in two of our clusters (QA and Production) after upgrading from version 25.1.7.20 to 25.7.4.11. It seems the system.query_views_log table completely stopped recording activity. No new log entries or table suffixes are being created.

We've investigated our system and can confirm that our materialized views are still processing data. The problem appears to be specific to the logging of view activity, not the functionality of the views themselves.

Here's a summary of what we observed and tried:

• The issue started immediately after upgrading to 25.7.4.11.

• We then tried upgrading to the latest stable version, 25.7.5.34, and the logs were still stopped.

• When we downgraded our QA cluster back to 25.1.7.20, logging resumed. Notably, the server also automatically recreated the query_views_log table that we had previously renamed during testing, and events started flowing into the new table.

• Running SYSTEM FLUSH LOGS; had no effect on the newer versions.

Configuration Details:

• The log_query_views setting is confirmed to be 1.

• We have no specific query_views_log configurations in our XML files.

• No configuration files were changed during the upgrade process.

• We checked the backward incompatibilities in the changelog but couldn't find anything related to this log table.

Since this is happening across multiple clusters, it seems less likely to be a unique environmental issue. Any ideas on what might have changed or what we could check next would be greatly appreciated.

Thanks!

Also created slack thread: https://clickhousedb.slack.com/archives/CU478UEQZ/p1756353749094149

Which ClickHouse versions are affected?

25.7.4.11 & 25.7.5.34

How to reproduce

As in the description

Expected behavior

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Error message and/or stacktrace

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Additional context

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