Centralize collection of catalog info needed early in the planner
authorRichard Guo <rguo@postgresql.org>
Tue, 22 Jul 2025 02:20:40 +0000 (11:20 +0900)
committerRichard Guo <rguo@postgresql.org>
Tue, 22 Jul 2025 02:20:40 +0000 (11:20 +0900)
commit904f6a593a06649f77597ab9a72ef97c21e39a93
treecbfe3d1f8063598e775e0a270b4ab32b8394ae9d
parente0d05295268e3811e6743403cb779f21d1662426
Centralize collection of catalog info needed early in the planner

There are several pieces of catalog information that need to be
retrieved for a relation during the early stage of planning.  These
include relhassubclass, which is used to clear the inh flag if the
relation has no children, as well as a column's attgenerated and
default value, which are needed to expand virtual generated columns.
More such information may be required in the future.

Currently, these pieces of catalog data are collected in multiple
places, resulting in repeated table_open/table_close calls for each
relation in the rangetable.  This patch centralizes the collection of
all required early-stage catalog information into a single loop over
the rangetable, allowing each relation to be opened and closed only
once.

Author: Richard Guo <guofenglinux@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: http://postgr.es/m/CAMbWs4-bFJ1At4btk5wqbezdu8PLtQ3zv-aiaY3ry9Ymm=jgFQ@mail.gmail.com
src/backend/optimizer/plan/planner.c
src/backend/optimizer/plan/subselect.c
src/backend/optimizer/prep/prepjointree.c
src/include/optimizer/prep.h