Fix fuzzy thinking about amcanmulticol versus amcaninclude. These flags should be independent: in particular an index AM should be able to say that it supports include columns without necessarily supporting multiple key columns. The included-columns patch got this wrong, possibly aided by the fact that it didn't bother to update the documentation.
While here, clarify some text about amcanreturn, which was a little vague about what should happen when amcanreturn reports that only some of the index columns are returnable. Noted while reviewing the SP-GiST included-columns patch, which quite incorrectly (and unsafely) changed SP-GiST to claim amcanmulticol = true as a workaround for this bug. Backpatch to v11 where included columns were introduced. Branch ------ REL_11_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/9cebe49524af365d48f9e63048c79f537d6b135c Modified Files -------------- doc/src/sgml/indexam.sgml | 35 +++++++++++++++++++++++++++-------- src/backend/commands/indexcmds.c | 4 ++-- 2 files changed, 29 insertions(+), 10 deletions(-)
