@Carlos,

Idle flushing is enabled only if early flushing behavior is enabled (innodb_max_dirty_pages_pct_lwm != 0).
[Default innodb_max_dirty_pages_pct_lwm == 0 so the issue].

Documentation could be updated to make a note of this.

ctutte, did you test krunalbauskar’s suggestion?

Note: In the MariaDB Server 10.5.7 and 10.5.8 releases, the parameter value innodb_max_dirty_pages_pct_lwm=0 (which is the default) meant that the page cleaner thread would always run in the background, as long as dirty pages exist in the buffer pool.

In MDEV-24537, the original meaning of the default value was restored: it means that there will be no separate background flushing, and nothing will be written out as long as:

• the share of dirty pages will not exceed innodb_max_dirty_pages_pct
• the last checkpoint age (LSN difference since the latest checkpoint) does not exceed innodb_log_file_size (minus some safety margin)
• we are not running out of space in the buffer pool, which could trigger eviction flushing

If you want background flushing to be as eager as it was in 10.5.7 and 10.5.8, I believe that the following should come close:

SET GLOBAL innodb_max_dirty_pages_pct_lwm=0.001;

Documentation updated at https://mariadb.com/kb/en/innodb-page-flushing/