This replaces all MemSet() calls with struct initialization where that
is easily and obviously possible. (For example, some cases have to
worry about padding bits, so I left those.)
(The same could be done with appropriate memset() calls, but this
patch is part of an effort to phase out MemSet(), so it doesn't touch
memset() calls.)
Reviewed-by: Ranier Vilela <ranier.vf@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://www.postgresql.org/message-id/9847b13c-b785-f4e2-75c3-12ec77a3b05c@enterprisedb.com
For GENERATED columns, we record all dependencies of the generation
expression as AUTO dependencies of the column itself. This means
that the generated column is silently dropped if any dependency
is removed, even if CASCADE wasn't specified. This is at least
a POLA violation, but I think it's actually based on a misreading
of the standard. The standard does say that you can't drop a
dependent GENERATED column in RESTRICT mode; but that's buried down
in a subparagraph, on a different page from some pseudocode that
makes it look like an AUTO drop is being suggested.
Change this to be more like the way that we handle regular default
expressions, ie record the dependencies as NORMAL dependencies of
the pg_attrdef entry. Also, make the pg_attrdef entry's dependency
on the column itself be INTERNAL not AUTO. That has two effects:
* the column will go away, not just lose its default, if any
dependency of the expression is dropped with CASCADE. So we
don't need any special mechanism to make that happen.
* it provides an additional cross-check preventing someone from
dropping the default expression without dropping the column.
catversion bump because of change in the contents of pg_depend
(which also requires a change in one information_schema view).
Per bug #17439 from Kevin Humphreys. Although this is a longstanding
bug, it seems impractical to back-patch because of the need for
catalog contents changes.
Discussion: https://postgr.es/m/17439-7df4421197e928f0@postgresql.org
This is a pure refactoring commit: there isn't (I hope) any functional
change.
StoreAttrDefault and RemoveAttrDefault[ById] are moved from heap.c,
reducing the size of that overly-large file by about 300 lines.
I took the opportunity to trim unused #includes from heap.c, too.
Two new functions for translating between a pg_attrdef OID and the
relid/attnum of the owning column are created by extracting ad-hoc
code from objectaddress.c. This already removes one copy of said
code, and a follow-on bug fix will create more callers.
The only other function directly manipulating pg_attrdef is
AttrDefaultFetch. I judged it was better to leave that in relcache.c,
since it shares special concerns about recursion and error handling
with the rest of that module.
Discussion: https://postgr.es/m/651168.1647451676@sss.pgh.pa.us
Amit Kapila
Peter Eisentraut
Alvaro Herrera
Tom Lane