MySQL Forums :: Performance :: order by primary key slowly


Advanced Search

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.

Options: ReplyQuote


Subject Views Written By Posted
order by primary key slowly 901 varky chan 04/05/2016 10:42PM
Re: order by primary key slowly 402 Øystein Grøvlen 04/06/2016 04:35AM
Re: order by primary key slowly 442 varky chan 04/06/2016 10:15AM
Re: order by primary key slowly 416 Peter Brawley 04/06/2016 11:23AM
Re: order by primary key slowly 488 varky chan 04/06/2016 08:11PM
Re: order by primary key slowly 382 Peter Brawley 04/06/2016 10:35PM
Re: order by primary key slowly 393 varky chan 04/07/2016 12:34AM
Re: order by primary key slowly 426 Øystein Grøvlen 04/07/2016 07:21AM
Re: order by primary key slowly 411 Peter Brawley 04/07/2016 10:20AM
Re: order by primary key slowly 391 varky chan 04/07/2016 11:26PM
Re: order by primary key slowly 375 Rick James 04/12/2016 07:42PM
Re: order by primary key slowly 395 Peter Brawley 04/06/2016 08:57AM
Re: order by primary key slowly 385 varky chan 04/06/2016 10:17AM


Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.