On 08/01/2017 07:13 PM, Jeff Janes wrote: > I think that HashSet is a Java-specific term. It is just a hash table > in which there is no data to store, just the key itself (and probably > a cash of the hashcode of that key), correct?
Yes. And in Java HashSet implemented on top of HashMap (: > I think a more general solution would be to get the planner and > executor to run the in-list query using the Hash Join, the same way it > runs the in-VALUES one. Have additional plan nodes big overhead? > I was impressed at how well the JSON and hstore worked, you might want > to look at how they do it. It is must be using an internal hash table > of some sort. JSONB and HSTORE keep sorted pairs and use binary search.
