Re: SQL:2011 application time

hi. some trivial issue:

in src/backend/catalog/index.c
/* * System attributes are never null, so no need to check. */
if (attnum <= 0)

since you already checked attnum == 0
so here you can just attnum < 0?
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ERROR:  column "valid_at" named in WITHOUT OVERLAPS is not a range type

IMHO, "named" is unnecessary.
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doc/src/sgml/catalogs.sgml
pg_constraint adds another attribute (column): contemporal, seems no doc entry.

also the temporal in oxford definition is "relating to time", here we
can deal with range.
So maybe  "temporal" is not that accurate?