On Thu, Aug 8, 2024 at 2:46 AM Peter Eisentraut <pe...@eisentraut.org> wrote: > When systable_beginscan() and systable_beginscan_ordered() choose an > index scan, they remap the attribute numbers in the passed-in scan keys > to the attribute numbers of the index, and then write those remapped > attribute numbers back into the scan key passed by the caller. This > second part is surprising and gratuitous. It means that a scan key > cannot safely be used more than once (but it might sometimes work, > depending on circumstances). Also, there is no value in providing these > remapped attribute numbers back to the caller, since they can't do > anything with that. > > I propose to fix that by making a copy of the scan keys passed by the > caller and make the modifications there.
This does have the disadvantage of adding more palloc overhead. -- Robert Haas EDB: http://www.enterprisedb.com
