Hello Hackers,
Please check this out,
It is an access method to scan a table sorting by the second column of an index, filtered on the first.
Queries like
SELECT x, y FROM grid
WHERE x in (array of Nx elements)
ORDER BY y, x
LIMIT M
Can execute streaming the rows directly from disk instead of loading everything.
Using btree index on (x, y)
On a grid with N x N will run by fetching only what is necessary
A skip scal will run with O(N * Nx) I/O, O(N x Nx) space, O(N x Nx * log( N * Nx)) comput (assuming a generic in memory sort)
The proposed access method does it O(M + Nx) I/O, O(Nx) space, and O(M * log(Nx)) compute.
Kind Regards,
Alexandre Felipe
Research & Development Engineer
