Allow CustomScan providers to say whether they support projections.
Previously, all CustomScan providers had to support projections,
but there may be cases where this is inconvenient. Add a flag
bit to say if it's supported.
Important item for the release notes: this is non-backwards-compatible
since the default is now to assume that CustomScan providers can't
project, instead of assuming that they can. It's fail-soft, but could
result in visible performance penalties due to adding unnecessary
Result nodes.
Sven Klemm, reviewed by Aleksander Alekseev; some cosmetic fiddling
by me.
Discussion: https://postgr.es/m/CAMCrgp1kyakOz6c8aKhNDJXjhQ1dEjEnp+6KNT3KxPrjNtsrDg@mail.gmail.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/955b3e0f9269639fb916cee3dea37aee50b82df0
Modified Files
--------------
doc/src/sgml/custom-scan.sgml | 13 ++++++++++---
src/backend/executor/execAmi.c | 17 +++++------------
src/backend/optimizer/plan/createplan.c | 8 ++++++++
src/include/nodes/extensible.h | 4 +++-
4 files changed, 26 insertions(+), 16 deletions(-)
