can you please suggest some ideas , how we can query on big tables and fasten them to get the output??
Thanks & Regards, Ebin
There are basically two "secrets" to performance in this case:
make sure that the join operation uses indexes
make sure that you have enough work_mem available
work_mem can be set in postgresql.conf, but also in every session individually. So don't set it too high generally, because it will be allocated for every sorting and hashing operation.