Re: please explain why this query isn't optimized

[Egor Egorov]

Dave Dyer <ddyer@stripped> wrote:

> Before I post it as a bug, perhaps someone can explain why
> this query is not optimized to use the index (it has to examine all 287k rows).
> 
> mysql> explain SELECT MAX(changed) FROM archived_stats where changed>0;
> | table          | type  | possible_keys | key     | key_len | ref  | rows    | Extra
>                    |
> | archived_stats | range | changed       | changed |       4 | NULL | 2878820 | Using
> where; Using index |

There are 2.878k rows, not 287k. 

And it's optimized as much as possible, the key is used. 





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