Index is not using

Hi All

I am facing query performance in one of my testing server.

How i can create index with table column name ?

EXPLAIN select xxx.* from xxx xxx where exists (select 1 from tmp
where mdc_domain_reverse like xxx.reverse_pd || '.%');

QUERY PLAN
-------------------------------------------------------------------------------------------
Nested Loop Semi Join (cost=0.00..315085375.74 rows=63 width=3142)
Join Filter: ((tmp.mdc_domain_reverse)::text ~~
((xxx.reverse_pd)::text || '.%'::text))
-> Seq Scan on xxx (cost=0.00..6276.47 rows=12547 width=3142)
-> Materialize (cost=0.00..31811.93 rows=1442062 width=17)
-> Seq Scan on tmp (cost=0.00..24601.62 rows=1442062 width=17)

saleshub=# EXPLAIN create table tmp2 as select xxx.* from xxx xxx
where exists (select 1 from tmp where mdc_domain_reverse like
'moc.ytirucesspc%') ;

QUERY PLAN
------------------------------------------------------------------------------------------------------------------------------------------------
Result (cost=0.06..6276.53 rows=12547 width=3142)
One-Time Filter: $0
InitPlan 1 (returns $0)
-> Index Scan using tmp_txt_idx_mdc on tmp (cost=0.00..8.53
rows=144 width=0)
Index Cond: (((mdc_domain_reverse)::text ~>=~
'moc.ytirucesspc'::text) AND ((mdc_domain_reverse)::text ~<~
'moc.ytirucesspd'::text))
Filter: ((mdc_domain_reverse)::text ~~ 'moc.ytirucesspc%'::text)
-> Seq Scan on xxx (cost=0.00..6276.47 rows=12547 width=3142)