InnoDB System Variables process is referred to as a “run” . During the merge phase, pairs of buffers of the specified size are read and merged. The larger the setting, the fewer runs and merges there are. This sort area is only used for merge sorts during index creation, not during later index maintenance operations. Buffers are deallocated when index creation completes. The value of this option also controls the amount by which the temporary log file is extended to record concurrent DML during online DDL operations. Before this setting was made configurable, the size was hardcoded to 1048576 bytes (1MB), which remains the default. During an  ALTER TABLE  or  CREATE TABLE  statement that creates an index, 3 buffers are allocated, each with a size defined by this option. Additionally, auxiliary pointers are allocated to rows in the sort buffer so that the sort can run on pointers (as opposed to moving rows during the sort operation). For a typical sort operation, a formula such as this one can be used to estimate memory consumption: (6 /*FTS_NUM_AUX_INDEX*/ * (3*@@GLOBAL.innodb_sort_buffer_size) + 2 * number_of_partitions * number_of_secondary_indexes_created * (@@GLOBAL.innodb_sort_buffer_size/dict_index_get_min_size(index)*/) * 8 /*64-bit sizeof *buf->tuples*/") @@GLOBAL.innodb_sort_buffer_size/dict_index_get_min_size(index) indicates the maximum tuples held.  2 * (@@GLOBAL.innodb_sort_buffer_size/ *dict_index_get_min_size(index)*/) * 8 /*64-bit size of *buf->tuples*/  indicates auxiliary pointers allocated. Note For 32-bit, multiply by 4 instead of 8. For parallel sorts on a full-text index, multiply by the  innodb_ft_sort_pll_degree  setting: (6 /*FTS_NUM_AUX_INDEX*/ * @@GLOBAL.innodb_ft_sort_pll_degree) • innodb_spin_wait_delay Command-Line Format --innodb-spin-wait-delay=# System Variable innodb_spin_wait_delay Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Integer Default Value 6 Minimum Value 0 Maximum Value (64-bit platforms,  ≤  8.0.13) 2**64-1 Maximum Value (32-bit platforms,  ≤  8.0.13) 2**32-1 3281