InnoDB Buffer Pool Thrashing
warningWorking set exceeds available buffer pool memory, forcing excessive disk reads. Buffer pool efficiency drops as pages are constantly evicted and reloaded, causing disk I/O saturation and query latency increases.
mysql.buffer_pool.data_pages shows low hit ratio (<95%) with mysql.innodb.buffer_pool_read_requests >> mysql.buffer_pool.operations (reads), mysql.innodb.data_reads elevated, and mysql.innodb.pending_normal_aio_reads > 0 sustained
Check buffer pool utilization: calculate (mysql.buffer_pool.pages - mysql.buffer_pool.pages{state='free'}) / mysql.buffer_pool.pages. If near 100%, working set exceeds buffer pool. Scale up instance class to increase available memory for buffer pool. Query performance_schema.table_io_waits_summary_by_table to identify tables causing most disk reads. Consider partitioning large tables or archiving old data. Monitor mysql.innodb.buffer_pool_wait_free - if non-zero, buffer pool is under severe pressure.