## What is a dirty page?

In a database, **dirty pages** are the pages that have been changed in the buffer cache but have not been written to the disk. These pages are periodically flushed, typically when the percentage of dirty pages exceeds the configured value of `innodb_max_dirty_pages_pct`.
 

## Impacts of flushing

When excessive flushing takes place, the throughput of database read/write operations can be reduced because the I/O capacity for ordinary read and write operations is reduced.

## Adaptive flushing

The InnoDB engine has a new algorithm to adapt the flushing based on heuristics derived from the speed of redo log generation and the number of dirty pages. The master thread decides how many pages to flush based on these numbers. This allows the flushing algorithm to deal with sudden workload spikes.

This feature can be enabled/disabled using the parameter `innodb_adaptive_flushing`.

What is adaptive flushing in MySQL?

In MySQL, adaptive flushing optimizes the flush rate of dirty pages based on workload metrics, improving performance during workload spikes.