WL#9707: Defaults change innodb_max_dirty_pages_pct=90
Affects: Server-8.0 — Status: Complete — Priority: Medium
In MySQL on OPC the defaults have been changed to innodb_max_dirty_pages_pct=90. We should consider if the same defaults apply to regular MySQL releases. In most cases they should. Upgrade Story ------------- With this change, InnoDB will allow a slightly greater number of modified ('dirty') pages in the buffer pool, at the risk of a lower amount of free-able space for other operations that require loading pages into the buffer pool. However in practice, InnoDB does not have the same reliance on innodb_max_dirty_pages_pct as it did in earlier versions of MySQL because of the introduction of a new low-watermark heuristic. With innodb_max_dirty_pages_pct_lwm, flushing activity increases at a much earlier point (default: 10%). Users wishing to revert to the previous behavior can set innodb_max_dirty_pages_pct=70 and innodb_max_dirty_pages_pct_lwm=0.
FR-1) The compiled default value of innodb-max-dirty-pages-pct changed from 75 to 90. NFR-1) Any changes required to MTR tests.
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