Tag - insert on duplicate key update

Why “insert … on duplicate key update” May Be Slow, by Incurring Disk Seeks

In my post on June 18th, I explained why the semantics of normal ad-hoc insertions with a primary key are expensive because they require disk seeks on large data sets. I previously explained why it would be better to use “replace into” or to use “insert ignore” over normal inserts. In this post, I […]

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