Abnormal performance difference between Postgres and MySQL

Hello,

I am doing a performance comparison between running
Jena<http://jena.sourceforge.net/>with MySQL and Postgres. I used the
8.3-community version of Postgres and
MySQL 5.0.67. I have run several queries to both MySQL and Postgres and all
of them took similar amount of time to execute except one. For the following
query to a table having 10,003,728 rows, MySQL takes 0.11 seconds to return
results whereas Postgres takes like 1 hour and 20 minutes!

Query:

select A0.Subj, A2.Obj From jena_g1t1_stmt A0, jena_g1t1_stmt A1,
jena_g1t1_stmt A2 Where A0.Prop='Uv::
http://prismstandard.org/namespaces/1.2/basic/isPartOf' AND A0.Obj='Uv::
http://www.utdallas.edu/~farhan.husain/IngentaConnect/issue1_1<http://www.utdallas.edu/%7Efarhan.husain/IngentaConnect/issue1_1>'
AND A0.GraphID=1 AND A0.Subj=A1.Subj AND A1.Prop='Uv::
http://www.w3.org/1999/02/22-rdf-syntax-ns#type' AND A1.Obj='Uv::
http://metastore.ingenta.com/ns/structure/Article' AND A1.GraphID=1 AND
A0.Subj=A2.Subj AND A2.Prop='Uv::
http://prismstandard.org/namespaces/1.2/basic/startingPage' AND
A2.GraphID=1;

Table:

Table "public.jena_g1t1_stmt"
Column | Type | Modifiers
---------+------------------------+-----------
subj | character varying(250) | not null
prop | character varying(250) | not null
obj | character varying(250) | not null
graphid | integer |
Indexes:
"jena_g1t1_stmt_ixo" btree (obj)
"jena_g1t1_stmt_ixsp" btree (subj, prop)

Machine: SunOS 5.10 Generic_127111-11 sun4u sparc SUNW, Sun-Fire-880
Memory: 4 GB
Number of physical processors: 2

I tried to re-arrage the query but each time the amount of time needed is
the same. Can anyone help me find the answer to why Postgres is taking so
much time?

I can provide any other information needed and also the data if anyone
wants.

Thanks and regards,

--
Mohammad Farhan Husain
Research Assistant
Department of Computer Science
Erik Jonsson School of Engineering and Computer Science
University of Texas at Dallas