> On Sun, Jun 16, 2019 at 5:03 PM Dmitry Dolgov <9erthali...@gmail.com> wrote: > > > I also agree with James that this should not be limited to Index Only > > Scans. From testing the patch, the following seems pretty strange to > > me: > > ... > > explain analyze select distinct on (a) a,b from abc order by a,b; > > explain analyze select distinct on (a) a,b,c from abc order by a,b; > > ... > > Yes, but I believe this limitation is not intrinsic to the idea of the patch, > and the very same approach can be used for IndexScan in the second example. > I've already prepared a new version to enable it for IndexScan with minimal > modifications, just need to rebase it on top of the latest changes and then > can post it. Although still there would be some limitations I guess (e.g. the > first thing I've stumbled upon is that an index scan with a filter wouldn't > work well, because checking qual causes with a filter happens after > ExecScanFetch)
Here is what I was talking about, POC for an integration with index scan. About using of create_skipscan_unique_path and suggested planner improvements, I hope together with Jesper we can come up with something soon.
v18-0001-Index-skip-scan.patch
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