Calculate row Sum.

sKwa

Hi!

I wrote UDScalar Function on C++ if any one need to calculate sum of row.

• Here is original question with examples.
• src code

Any feedback would be greatly appreciated!

Exmaple

Data:

daniel=> select * from eldj ;
 col  | m01 | m02 | m03 | m04 | m05
------+-----+-----+-----+-----+-----
 key1 |   0 |   0 |   1 |   0 |   0
 key2 |   1 |   1 |   0 |   1 |   1
 key3 |   0 |   0 |   0 |   0 |   1
 key4 |   0 |   0 |   1 |   1 |   1
 key5 |   1 |   1 |   0 |   0 |   0
 key6 |   0 |   1 |   0 |   0 |   0
(6 rows)

Usage:

daniel=> select col, rowsum(* using parameters exclude='col') as 'SUM_TRUE' from eldj;
 col  | SUM_TRUE
------+----------
 key1 |        1
 key2 |        4
 key3 |        1
 key4 |        3
 key5 |        2
 key6 |        1
(6 rows)

Ben_Vandiver

I would try to move the exclude check into the setup() function - compute the column indexes to ignore in the processBlock function. That way you avoid string comparison for every row/column.

sKwa

Hi @Ben_Vandiver!

avoid string comparison for every row/column.

I wanted to do it, but if nobody needs it then I'm not going to invest in it.

So far its just a concept, there are a couple things I need to do:

• columns type validation
• logging
• extend function for other numeric types(may be)
• Handling Cancel Requests (not sure, because its a scalar function and ^C should work fine in this case)

Thnx for your feedback.

Jim_Knicely

Thanks for sharing this @sKwa!