Re: [SQL] [PERFORM] 7.3.1 index use / performance

On Tue, 7 Jan 2003, Tom Lane wrote:

> There is no way that adding the filter condition should have reduced the
> estimated runtime for this plan --- reducing the estimated number of
> output rows, yes, but not the runtime. And in fact I can't duplicate

My case persists:
After clean install of the database, and after vacuum analyze,
i get

dynacom=# EXPLAIN ANALYZE select
FUELCONSUMPTION,rpm,Steam_Hours,voyage_activity,ldin from noon where
report_date between '2002-01-07' and '2003-01-07';
QUERY PLAN

-----------------------------------------------------------------------------------------------------------------------------
Index Scan using noonf_date on noon (cost=0.00..16458.54 rows=10774
width=39) (actual time=0.13..205.86 rows=7690 loops=1)
Index Cond: ((report_date >= '2002-01-07'::date) AND (report_date <=
'2003-01-07'::date))
Total runtime: 233.22 msec

dynacom=# EXPLAIN ANALYZE select
FUELCONSUMPTION,rpm,Steam_Hours,voyage_activity,ldin from noon where
report_date between '2002-01-07' and '2003-01-07' and v_code='4500';
QUERY PLAN

------------------------------------------------------------------------------------------------------------------------
Index Scan using noonf_vcode on noon (cost=0.00..3092.52 rows=83
width=39) (actual time=0.15..15.08 rows=373 loops=1)
Index Cond: (v_code = '4500'::character varying)
Filter: ((report_date >= '2002-01-07'::date) AND (report_date <=
'2003-01-07'::date))
Total runtime: 16.56 msec
(4 rows)

I thought PostgreSQL in some sense (hub.org) used FreeBSD,
is there any 4.7 FreeBSD server with pgsql 7.3.1 you could use?

==================================================================
Achilleus Mantzios
S/W Engineer
IT dept
Dynacom Tankers Mngmt
Nikis 4, Glyfada
Athens 16610
Greece
tel: +30-10-8981112
fax: +30-10-8981877
email: achill(at)matrix(dot)gatewaynet(dot)com
mantzios(at)softlab(dot)ece(dot)ntua(dot)gr