Description
While fetching from KV on inner table we do 1 key at time and not able to utilize the bulk get.
If we implement block nested loop we can take advantage of the bulk get and improve performance.
https://en.wikipedia.org/wiki/Block_nested_loop
https://www.informatik.hu-berlin.de/de/forschung/gebiete/wbi/teaching/archive/sose05/dbs2/slides/09_joins.pdf
https://www.youtube.com/watch?v=6utE58v_qiY
https://dev.mysql.com/doc/refman/5.6/en/bnl-bka-optimization.html
https://www.d.umn.edu/~rmaclin/cs4611/notes/Ch14a_Opimpl_Joins.pdf
https://mariadb.com/kb/en/mariadb/block-based-join-algorithms/