Neil Conway <[EMAIL PROTECTED]> writes: > On Mon, 2004-11-15 at 10:19 -0500, Tom Lane wrote: >> I'm not familiar with the details of the GiST code, but would it work to >> generalize PickSplit to return a three-way classification? That is, >> instead of actually splitting the node, have it identify each item as >> "definitely left", "definitely right", or "don't care" (think "less", >> "greater", or "equal to" the desired split value).
> I had thought about this solution, but I was worried that it will > actually make GiST a less general framework, because it requires that > the PickSplit() method effectively order the leaves of the tree. For > btree that is a reasonable assumption to make, but I'm not sure if it > can or should be made in general. If there are no don't-care cases, then you're effectively saying that the first column's PickSplit has sole control over the tree shape, which is where we're at now. ISTM the entire point of a multi-column index is that the first column has duplicates, or at least values that are similar enough to qualify as don't-cares. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend