mysql

MySQL Filesort

Understanding the "Using filesort" operation in MySQL queries.

SELECT * FROM orders ORDER BY order_date DESC;

"Using filesort" means MySQL must perform an extra pass to find out how to retrieve the rows in sorted order. The sort is done by traversing all rows according to the join type and storing the sort key and pointer to the row. This can be expensive for large result sets.

Interactive Execution Plan

EXPLAIN Output

Run: EXPLAIN FORMAT=JSON your_query; or EXPLAIN your_query;

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