MySQL :: Hash join in MySQL 8The build phase The literature usually divides hash join in two phases; the build phase and the probe phase. In the build phase, the server builds an in-memory hash table where rows from one of the inputs are stored, using the join attribute(s) as the hash table key. This input is also known as the build input, and let us assume that ‘countries’ is designated as the build input. Ideally, the serve
