Block Nested Loops Join

Use one page as an input buffer for scanning the inner S, one page as the output buffer, and use all remaining pages to hold ``block’’ of outer R.
- For each matching tuple r in R-block, s in S-page, add <r, s> to result. Then read next R-block, scan S, etc.

. . .

R & S

Hash table for block of R

(k < B-1 pages)

Input buffer for S

Output buffer

Join Result

Use one page as an input buffer for scanning the inner S, one page as the output buffer, and use all remaining pages to hold ``block’’ of outer R.