Re: Approach to extract top records from table based upon aggregate

2015-11-02 19:14 GMT-03:00 droberts <david(dot)roberts(at)riverbed(dot)com>:

> Hi, I have a table that contains call records. I'm looking to get only
> records for users who made the most calls over a particular time duration
> in
> an efficient way.
>
> calls()
>
> time, duration, caller_number, dialed_number
>
>
>
> -- query to get top 10 callers
> select caller_number, count(1) from calls group by caller_number order by
> calls desc limit 10
>
> --my current query to get those callers
>
> select * from call where caller_number in (above query)
>
>
> It works but I was hoping for something a little more efficient if anyone
> has an idea.
>
>
I think that almost every time based tables, should be partitioned. Also,
depending on your workload you can create lazy views over the last entries
in calls table during a particular time frame.

Probably in this particular case, you will want to dig into more underneath
design in order to get the best performance.

Doing a lazy view with that query, you can use the top n of it and get less
callers if you need to (or more if you want to expand the feature).

Hope it helps,

--
--

Emanuel Calvo

Twitter: 3manuek
LinkedIn: http://ar.linkedin.com/in/ecbcbcb/