> On Tue, Mar 22, 2022 at 04:55:49PM -0400, Tom Lane wrote: > Peter Geoghegan <p...@bowt.ie> writes: > > Like many difficult patches, the skip scan patch is not so much > > troubled by problems with the implementation as it is troubled by > > *ambiguity* about the design. Particularly concerning how skip scan > > meshes with existing designs, as well as future designs -- > > particularly designs for other MDAM techniques. I've started this > > thread to have a big picture conversation about how to think about > > these things. > > Peter asked me off-list to spend some time thinking about the overall > direction we ought to be pursuing here. I have done that, and here > are a few modest suggestions.
Thanks. To make sure I understand your proposal better, I have a couple of questions: > In short: I would throw out just about all the planner infrastructure > that's been proposed so far. It looks bulky, expensive, and > drastically undercommented, and I don't think it's buying us anything > of commensurate value. Broadly speaking planner related changes proposed in the patch so far are: UniqueKey, taken from the neighbour thread about select distinct; list of uniquekeys to actually pass information about the specified loose scan prefix into nbtree; some verification logic to prevent applying skipping when it's not supported. I can imagine taking out UniqueKeys and passing loose scan prefix in some other form (the other parts seems to be essential) -- is that what you mean?
