----As per Simon Riggs suggestion:

--------------------------------------
----With Single column bigint index:
--Schema
create table tbl2(id1 int, id2 bigint, id3 int);
create index idx2 on tbl2(id2);

--Procedure to insert 1M data:

insert into tbl2 values(1,generate_series(1, 1000000), 2);

--Procedure to select data 1000 times (1000 times selected to make data more appropriate.)
create or replace function select_data(count1 int) returns void
AS
$$
declare
	x int;
Begin
	for i IN 1..count1 loop
		select count(*) into x from tbl2 where id2>990000; 
	end loop;	
End;				  
$$	language plpgsql;

select select_data(1000);

--------------------------------------
----With Multiple column bigint index:

create table tbl3(id1 int, id2 bigint, id3 bigint, id4 bigint);
create index idx3 on tbl3(id2, id3, id4);

insert into tbl3 values(1,generate_series(1, 1000000), generate_series(1, 1000000), generate_series(1, 1000000));

--Procedure to select data 1000 times (1000 times selected to make data more appropriate.)
create or replace function select_data_multi_bigint(count1 int) returns void
AS
$$
declare
	x int;
Begin
	for i IN 1..count1 loop
		select count(*) into x from tbl3 where id2>990000 and id3>990000 and id4>990000; 
	end loop;	
End;				  
$$	language plpgsql;

select select_data_multi_bigint(1000);		


--------------------------------------
---5 column index with mixed text and integers

--Schema
create table tbl4(id1 int, id2 varchar(10), id3 int, id4 varchar(10), id5 int, id6 int);
create index idx4 on tbl4(id2, id3, id4, id5, id6);

--Procedure to insert 1M data:

create or replace function insert_data_mix_text_int(count1 int, count2 int) returns void
AS
$$
Begin
	for i IN 1..count1 loop
		insert into tbl4 values(i, 'a', i, 'a', i, i);
	end loop;	
	
	for i IN count1+1..count2 loop
		insert into tbl4 values(i, 'b', i, 'b', i, i);
	end loop;	
End;				  
$$	language plpgsql;

select insert_data_mix_text_int(990000, 1000000);

--Procedure to select data 1000 times (1000 times selected to make data more appropriate.)
create or replace function select_data_mix_text_int(count1 int) returns void
AS
$$
declare
	x int;
Begin
	for i IN 1..count1 loop
		select count(*) into x from tbl4 where id2>'a' and id3>990000 and id4>'a' and id5>990000 and id6>990000; 
	end loop;	
End;				  
$$	language plpgsql;

select select_data_mix_text_int(1000);