Varadha,
> we install postgres using RPM so how do I go about it then.
Sorry, no can do. If you want to use special compile-time options, you
cannot use RPMs. RPMs are for people who want the default install.
The good news is that 7.2 came out yesterday. Within a few weeks, you
should see RPMs for your chosen distribution appearing. The reason
that this is good news for you is that (I believe) Tom and Bruce made
the default arguments/parameters 24 in version 7.2 instead of 16.
Of course, compiling Postgres isn't hard:
pg_dumpall > database_backup
su root
tar -xvzf postgresql-7.2.tgz
cd postgresql-7.2
./configure
make
su postgres
make install
<postgres dir>/bin/initdb
pg_restore database_backup
-Josh