The JOIN condition doesn't have to be an equality – it can be any condition you want. JOIN doesn't interpret the JOIN condition, it only checks if the rows satisfy the given condition.

The group of pages nested loop join is an optimization over the page-based nested loop join. Instead of reading a single page of R at a time before scanning S, it reads over M-1 pages of …

We sequentially read R and S blocks one block at a time, and join them (using the join algrothm) Q: How many disk IOs (block reads/writes) for R and S during join stage?

Formally, we refer to the inner join operator as a Theta Join ( θ). The θ refers to the join condition, so for the expression from above, the θ join condition is cats.name = dogs.name.

Perform join by examining a variable at a time instead of a relation at a time. → First considered by other Germans in 2008. The runtime of a WCOJ algorithm is bounded by the output size of …

Key question: How to execute a join fast? Q: Where does 2 come from? A: Replacement selection. Memory ... ... Partition overflow and additional techniques When two algorithms are …

Lecture 10d: Join Algorithms: Index-nested Loop Joins (and other use of Index) Notation Remember our disk-memory diagram ?