Bitwise computation and count number of set bits afterward - ruby-on-rails

Question

I have a table:
create_table "fingerprint" do |t|
t.bit "fp1", limit: 64
t.bit "fp2", limit: 64
t.bit "fp3", limit: 64
t.bit "fp4", limit: 64
t.bit "fp5", limit: 64
end
fp1 | fp2 | fp3 | fp4 | fp5
---------------------------
001 | 010 | 011 | 100 | 101
And an array of 5 elements
fp = [5,4,3,2,1]
I'd like and bitwise each record of the table with each element fp and then count the total number of set bits over 5 columns.
For example:
(001 & 5) = 001
(010 & 4) = 000
(011 & 3) = 011
(100 & 2) = 000
(101 & 1) = 001
Total number of set bits: 4
I want to loop this procedure in every row of my table. Please help me with an efficient way to do it (the table has about 100k rows).
Thank you in advance.

Answer 1

The example for the type bit(3). You can easily adapt this for bit(64):
create table the_table (fp1 bit(3), fp2 bit(3), fp3 bit(3), fp4 bit(3), fp5 bit(3));
insert into the_table values
('001', '010', '011', '100', '101'),
('101', '011', '111', '110', '101');
with the_array(arr) as (
values (array[5,4,3,2,1])
),
new_values as (
select
fp1 & arr[1]::bit(3) n1,
fp2 & arr[2]::bit(3) n2,
fp3 & arr[3]::bit(3) n3,
fp4 & arr[4]::bit(3) n4,
fp5 & arr[5]::bit(3) n5
from the_table
cross join the_array
)
select
*,
length(
translate(
concat(n1::text, n2::text, n3::text, n4::text, n5::text),
'0',
'')
) bit_set
from new_values;
n1 | n2 | n3 | n4 | n5 | bit_set
-----+-----+-----+-----+-----+---------
001 | 000 | 011 | 000 | 001 | 4
101 | 000 | 011 | 010 | 001 | 6
(2 rows)