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Re: order by primary key slowly
Posted by: Peter Brawley
Date: April 07, 2016 10:20AM

> It is obvious that the second option takes longer than the first query
> since it needs to read more than 5 times as many index entries ...

What confuses us users is that Explain suggests the opposite: it will read 5,465,723 rows for the quicker query, 1,000,010 for the slower one. Explain fails to explain that the PK index is slower to read.

> and in addition sort all the IDs.

Yes.

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