Re: Approach to extract top records from table based upon aggregate
| От | Emanuel Calvo |
|---|---|
| Тема | Re: Approach to extract top records from table based upon aggregate |
| Дата | |
| Msg-id | CAE--4s8c3ZsFi0Wi8sV_KA=pSJUAJpuDxxtc8Y+g6dcfo=07Eg@mail.gmail.com обсуждение исходный текст |
| Ответ на | Approach to extract top records from table based upon aggregate (droberts <david.roberts@riverbed.com>) |
| Список | pgsql-general |
2015-11-02 19:14 GMT-03:00 droberts <david.roberts@riverbed.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,
-- В списке pgsql-general по дате отправления: