Ruby on Rails

On Jul 22, 2015, at 11:27 PM, Mohit Sindhwani <mo_mail@onghu.com> wrote:
>
> Hi Scott,
>
> On 23/7/2015 11:54 AM, Scott Ribe wrote:
>> On Jul 22, 2015, at 9:10 PM, Mohit Sindhwani <mo_mail@onghu.com> wrote:
>>> We have tried this and the query is quite a bit slower. Filtering to the last 900k records before doing the recorded_on part helped speed it up.
>> I don't understand how that could possibly be the case if there's an index on recorded_on.
>
> Because it was the count(distinct x) that was the problem :)
> Doing only a count(*) is faster without the subquery... and is what we have switched to.

So does the limit reduce it to less than 1 day's rows?

--
Scott Ribe
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