On Mon, Dec 5, 2011 at 3:12 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> On Mon, Dec 5, 2011 at 2:47 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> Peter Eisentraut <peter_e@gmx.net> writes:
>>>> To clarify, I believe the rule is that the first variable-length field
>>>> can be accessed as a struct field. Are there any exceptions to this?
>
>>> If it is known not null, yes, but I wonder just how many places actually
>>> depend on that.
>
>> My impression is that all the varlena fields also allow nulls.
>
> See MARKNOTNULL in bootstrap.c. I think the exceptions were designed to
> protect direct accesses to pg_index.
Hmm, OK.
rhaas=# select r.relname, a.attname, a.atttypid::regtype from pg_class
r, pg_attribute a where relnamespace=11 and relkind='r' and attrelid =
r.oid and a.attnotnull and a.attlen<0; relname | attname | atttypid
------------+--------------+------------pg_proc | proargtypes | oidvectorpg_index | indkey |
int2vectorpg_index | indcollation | oidvectorpg_index | indclass | oidvectorpg_index | indoption |
int2vectorpg_trigger| tgattr | int2vector
(6 rows)
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
