Re: Help on indexing timestamps

On Fri, 7 Mar 2003, Andre Schubert wrote:

> On Fri, 7 Mar 2003 13:01:16 -0200 (GMT+2)
> Achilleus Mantzios <achill@matrix.gatewaynet.com> wrote:
> 
> > On Fri, 7 Mar 2003, Andre Schubert wrote:
> > 
> > > Hi all,
> > > 
> > > i have a little problem on indexing a table which contains
> > > about 4 millions of traffic-data.
> > > My problem is, that a want to select all data from
> > > a specific month from a specific ip and this select should use the index.
> > > I use the following select:
> > 
> > Did you try to use BETWEEN ??
> > E.g.
> > ... and time_stamp between '2003-01-01 00:00:00'::timestamp and 
> > '2003-02-01 00:00:00'::timestamp
> > 
> 
> Yes and it works if i write the dates by hand, every new month.
> But the query is executed automatically and i dont want
> to write in the dates before the query is executed. Maybe the
> the start and enddate should also be alculated with sql,
> because i want to create a view from this statement and execute it every month.
> Or did i miss something.

You could have an index on the 
whole 
date_trunc('month',tbl_traffic.time_stamp),ip

How does it perform?

> 
> Regards, as
> 
> > > 
> > > db_nmkm3aue=# explain analyze select sum(inet_up+inet_down) from tbl_traffic where
date_trunc('month',tbl_traffic.time_stamp)::timestamptz= date_trunc('month',now() - timespan('1 months')) and ip =
'80.243.38.57';
> > > NOTICE:  QUERY PLAN:
> > > 
> > > Aggregate  (cost=116.30..116.30 rows=1 width=16) (actual time=1620.79..1620.79 rows=1 loops=1)
> > >   ->  Index Scan using idx_ip_time_stamp on tbl_traffic  (cost=0.00..116.30 rows=1 width=16) (actual
time=1216.79..1579.89rows=5232 loops=1)
 
> > > Total runtime: 1620.94 msec
> > > 
> > > But it takes a long time to select the traffic for all Ips.
> > > Is there a way to select these data with using the index correctly ?
> > > 
> > > Thanks in advance
> > > 
> > > BTW: Table-schema as follows
> > > 
> > > db_test=# \d tbl_traffic
> > >                 Table "tbl_traffic"
> > >    Column   |           Type           | Modifiers 
> > > ------------+--------------------------+-----------
> > >  time_stamp | timestamp with time zone | not null
> > >  ip         | inet                     | 
> > >  local_up   | bigint                   | not null
> > >  local_down | bigint                   | not null
> > >  inet_up    | bigint                   | not null
> > >  inet_down  | bigint                   | not null
> > > Indexes: idx_ip_time_stamp
> > > 
> > > db_test=# \d idx_ip_time_stamp
> > >        Index "idx_ip_time_stamp"
> > >    Column   |           Type           
> > > ------------+--------------------------
> > >  ip         | inet
> > >  time_stamp | timestamp with time zone
> > > 
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> > 
> > -- 
> > ==================================================================
> > Achilleus Mantzios
> > S/W Engineer
> > IT dept
> > Dynacom Tankers Mngmt
> > Nikis 4, Glyfada
> > Athens 16610
> > Greece
> > tel:    +30-210-8981112
> > fax:    +30-210-8981877
> > email:  achill@matrix.gatewaynet.com
> >         mantzios@softlab.ece.ntua.gr
> > 
> > 
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-- 
==================================================================
Achilleus Mantzios
S/W Engineer
IT dept
Dynacom Tankers Mngmt
Nikis 4, Glyfada
Athens 16610
Greece
tel:    +30-210-8981112
fax:    +30-210-8981877
email:  achill@matrix.gatewaynet.com       mantzios@softlab.ece.ntua.gr