Re: Help on indexing timestamps

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

>
> 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..1579.89 rows=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
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo(at)postgresql(dot)org so that your
> message can get through to the mailing list cleanly
>

--
==================================================================
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(at)matrix(dot)gatewaynet(dot)com
mantzios(at)softlab(dot)ece(dot)ntua(dot)gr