InnoDB System Variables •A setting of 1 flushes contiguous dirty pages in the same extent. •A setting of 2 flushes dirty pages in the same extent. When the table data is stored on a traditional HDD storage device, flushing such neighbor pages in one operation reduces I/O overhead (primarily for disk seek operations) compared to flushing individual pages at different times. For table data stored on SSD, seek time is not a significant factor and you can set this option to 0 to spread out write operations. For related information, see Section 15.8.3.5, “Configuring Buffer Pool Flushing” . • innodb_flush_sync Command-Line Format --innodb-flush-sync[={OFF|ON}] System Variable innodb_flush_sync Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Boolean Default Value ON The  innodb_flush_sync  variable, which is enabled by default, causes the  innodb_io_capacity setting to be ignored during bursts of I/O activity that occur at checkpoints. To adhere to the I/O rate defined by the  innodb_io_capacity  setting, disable  innodb_flush_sync . For information about configuring the  innodb_flush_sync  variable, see Section 15.8.7, “Configuring InnoDB I/O Capacity” . • innodb_flushing_avg_loops Command-Line Format --innodb-flushing-avg-loops=# System Variable innodb_flushing_avg_loops Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Integer Default Value 30 Minimum Value 1 Maximum Value 1000 Number of iterations for which  InnoDB  keeps the previously calculated snapshot of the flushing state, controlling how quickly adaptive flushing responds to changing workloads. Increasing the value makes the rate of flush operations change smoothly and gradually as the workload changes. Decreasing the value makes adaptive flushing adjust quickly to workload changes, which can cause spikes in flushing activity if the workload increases and decreases suddenly. For related information, see Section 15.8.3.5, “Configuring Buffer Pool Flushing” . 3247