create function get_table_value_plpgsql(id int)
returns varchar
language plpgsql
as
$$
declare
   table_value varchar;
begin
   select name
   from product1
   where product1.id = get_table_value_plpgsql.id
   into table_value;

   return table_value;
end;
$$;

create function get_table_value_sql1(id int)
returns varchar
language sql
as
$$
  SELECT name
  FROM product1
  WHERE id=id;
$$;

-- my_benchmark_sql.sql

\set id random(1, 100000)
BEGIN;
SELECT get_table_value_sql(:id);
END;

pgbench -c 10 -T 300 flyway_test -f my_benchmark_sql.sql

-- my_benchmark_plpgsql.sql

\set id random(1, 100000)
BEGIN;
SELECT get_table_value_plpgsql(:id);
END;

pgbench -c 10 -T 300 flyway_test -f my_benchmark_pplgsql.sql