On Thu, Jun 6, 2019 at 10:03 AM Alvaro Herrera <alvherre@xxxxxxxxxxxxxxx> wrote: > If you are saying that you think that Postgres should support primary > keys that don't necessarily overlap partition keys, then I agree with > you. Please send a patch to implement that capability. FWIW, I could probably be convinced to work on the nbtree parts of global indexes if there was a reasonably worked out design that had some momentum behind it. I would at least need to know what the partition identifiers will need to look like in indexes. Andres has suggested that I work on variable-width table identifiers in nbtree for the benefit of pluggable storage engines, but I don't have much enthusiasm for the idea of doing that without delivering a clear benefit to users in the same release. It seems pretty obvious to me that the right general approach for global indexes is to make the partition identifier a tiebreaker column that comes right before the heap TID tiebreaker column (which would be per-partition). It probably needs to be variable-width, so that the overhead isn't too bad most of the time. I don't think that it's necessary to remove the restriction on the size of relations for global indexes, though maybe global indexes could focus our attention on that problem. -- Peter Geoghegan
