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You can also use the mysqladmin processlist  and mysqladmin kill  commands to examine and kill threads. 

When you use KILL , a thread-specific kill flag is set for the thread. In most cases, it might take some time for the thread to die because the kill flag is checked only at specific intervals: 

•During SELECT  operations, for ORDER BY  and GROUP BY  loops, the flag is checked after reading a block of rows. If the kill flag is set, the statement is aborted. 

• ALTER TABLE  operations that make a table copy check the kill flag periodically for each few copied rows read from the original table. If the kill flag was set, the statement is aborted and the temporary table is deleted. 

The KILL  statement returns without waiting for confirmation, but the kill flag check aborts the operation within a reasonably small amount of time. Aborting the operation to perform any necessary cleanup also takes some time. 

•During UPDATE  or DELETE  operations, the kill flag is checked after each block read and after each updated or deleted row. If the kill flag is set, the statement is aborted. If you are not using transactions, the changes are not rolled back. 

• GET_LOCK()  aborts and returns NULL . 

•If the thread is in the table lock handler (state: Locked ), the table lock is quickly aborted. 

•If the thread is waiting for free disk space in a write call, the write is aborted with a “disk full”  error message. 

• EXPLAIN ANALYZE  aborts and prints the first row of output. This works in MySQL 8.0.20 and later. 

## 13.7.8.5 LOAD INDEX INTO CACHE Statement 

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LOAD INDEX INTO CACHE tbl_index_list  [, tbl_index_list ] ... tbl_index_list : tbl_name [PARTITION ( partition_list )] [{INDEX|KEY} ( index_name [, index_name ] ...)] [IGNORE LEAVES] partition_list : { partition_name [, partition_name ] ... | ALL } 

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## Warning 

Killing a REPAIR TABLE  or OPTIMIZE TABLE  operation on a MyISAM  table results in a table that is corrupted and unusable. Any reads or writes to such a table fail until you optimize or repair it again (without interruption). 

The LOAD INDEX INTO CACHE  statement preloads a table index into the key cache to which it has been assigned by an explicit CACHE INDEX  statement, or into the default key cache otherwise. 

LOAD INDEX INTO CACHE  applies only to MyISAM  tables, including partitioned MyISAM  tables. In addition, indexes on partitioned tables can be preloaded for one, several, or all partitions. 

The IGNORE LEAVES  modifier causes only blocks for the nonleaf nodes of the index to be preloaded. 

