Is that a bug?

Hi,
I have some problems with postgresql 7.0.3 running on
Slackware linux 7.1.

I have a table with about 25 milion records:

create table gsc_act(reg_id int2,id int2,ra int4, de
int4,mag int2);

i created 2 indexes:

create index gsc_act_de on gsc_act(de);
create index gsc_act_rd on gsc_act(de,ra);

so every thing was ok with queries:
1. select * from gsc_act where de>=-300000
   and de<300000 and ra<=600000 and ra>=0;
2. select * from gsc_act where de>=-300000
   and de<300000 and ra<=600000 and ra>=0
   and mag<300;

except the second one was too slow and I created third
index:

create index gsc_act_rdm on gsc_act(de,ra,mag);

I executed query 2 and it hang for 5-6 min with
permanent disk activity even Ctrl-C could not stop it.
I killed postmaster and droped the third index. Now
both queries hang the same way. Is there any way to
fix it? This are the most used queries with the
table(only the values are different).
Is this some bug in postgres?
Please help!

Rumen

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