Fwd: postgres join query.

Hi,

I am using join query as below.

java code
=================
sqlQuery="insert into locations_graphic_map_ksk(chain,
screen,template,location,language,graphic_up_filename,graphic_up,graphic_up_descr,graphic_dn_filename,graphic_dn,graphic_dn_descr)"
+ " select t1.chain, t1.screen, t1.template,
t1.location, t1.language, t1.graphic_up_filename, t2.graphic,
t2.graphic_descr, t1.graphic_dn_filename, t3.graphic, t3.graphic_descr "
+ "from locations_graphic_map_ksk_tmp as t1,
loc_graphic_map_ksk_up as t2, loc_graphic_map_ksk_dn as t3 where
t1.graphic_up_filename=t2.graphic_filename and
t1.graphic_dn_filename=t3.graphic_filename";

st=conn.createStatement();
st.executeUpdate(sqlQuery);

I have one doubt that, are all results get loaded to main memory from join
then it does insertion
or it retrieves few records and do insertion and so on?

Please help.

Thanks,
rahul