Re: Correlating Asterisk CDRs - Mailing list pgsql-sql

On Dec 7, 2011, at 6:34 AM, Raj Mathur (राज माथुर) wrote:

> Hi,
>
> I'm trying to correlate Call Data Records (CDRs) from two Asterisk
> servers, one of which uses the other for telephony.  The data is in
> the tables cdr and cdr2.  With some indexes, the query and explain
> result are:
>
> explain analyse select cdr.calldate, cdr2.calldate,
> (cdr2.calldate-cdr.calldate) as rtdur, cdr.clid, cdr.dst, cdr2.src,
> cdr2.dst, cdr2.dstchannel, cdr2.lastapp, cdr2.duration,
> cdr2.disposition from cdr, cdr2 where cdr2.calldate >= cdr.calldate
> and cdr.clid=cdr2.clid and cdr.dst=substring(cdr2.dst from 4) order by
> cdr.calldate, cdr2.calldate, cdr.clid limit 100;
>
>                                                             QUERY PLAN
                  
>
---------------------------------------------------------------------------------------------------------------------------------------------
> Limit  (cost=46782.15..46782.40 rows=100 width=109) (actual time=4077.866..4078.054
> rows=100 loops=1)
>   ->  Sort  (cost=46782.15..46785.33 rows=1272 width=109) (actual time=4077.863..4077.926
> rows=100 loops=1)
>         Sort Key: cdr.calldate, cdr2.calldate, cdr.clid
>         Sort Method:  top-N heapsort  Memory: 42kB
>         ->  Merge Join  (cost=2.95..46733.54 rows=1272 width=109) (actual
> time=0.070..3799.546 rows=168307 loops=1)
>               Merge Cond: (((cdr.clid)::text = (cdr2.clid)::text) AND ((cdr.dst)::text =
> "substring"((cdr2.dst)::text, 4)))
>               Join Filter: (cdr2.calldate >= cdr.calldate)
>               ->  Index Scan using ick1 on cdr  (cost=0.00..34667.86 rows=208798
> width=43) (actual time=0.022..434.246 rows=208798 loops=1)
>               ->  Index Scan using i2k1 on cdr2  (cost=0.00..9960.89 rows=65449 width=88)
> (actual time=0.011..391.599 rows=240981 loops=1)
> Total runtime: 4078.184 ms
> (10 rows)
>
> Is there any way to make this query faster?  I already have an index
> i2k1 on substring(cdr2.dst from 4), which is being used.
>
> Application
> -----------
>
> I'm looking for all caller records in cdr2 that have the same callerid
> (clid) and destination (dst) and were started on cdr2 after they were
> started on cdr.  cdr2.dst is the same as cdr.dst but with a
> 3-character prefix.
>
> Regards,
>
> -- Raj
> --
> Raj Mathur                          || raju@kandalaya.org   || GPG:
> http://otheronepercent.blogspot.com || http://kandalaya.org || CC68
> It is the mind that moves           || http://schizoid.in   || D17F
>
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You have a non-equi join in there (cdr2.calldate >= cdr.calldate). I would try to get rid of that. It's increasing the
numberof rows in the result set and will only get worse as your data set grows. 

Brent.