Dear All, I took a look at the source code for hash join this morning and I realized that the block nested loop join is somewhat similar to that.
Thanks for the discussions. Bramandia R. On Fri, Oct 10, 2008 at 8:19 PM, Tom Lane <[EMAIL PROTECTED]> wrote: > Gregory Stark <[EMAIL PROTECTED]> writes: > > So the use case of a real block nested loop would be doing a cartesian > join of > > two large tables where neither fits in RAM. That does seem like it might > be > > kind of narrow given how large the output would be. > > Yeah. If you have a hashable join condition then our existing batched > hash join code should be roughly equivalent to this method. So the use > case is joining a couple of large tables with an un-hashable, > un-indexable join condition (or none at all, ie cross product) and that > just isn't something we hear people wanting to do a lot. I can't really > see why we'd bother maintaining extra code for block nested loop. > > regards, tom lane >
