Robert Haas <robertmh...@gmail.com> writes: >> On Jun 20, 2014, at 10:01 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> Some of my Salesforce colleagues are looking into making every system >> catalog be declared with a true primary key. They came across the >> fact that pg_seclabel and pg_shseclabel are declared with unique >> indexes that include the "provider" column, but that column does not >> get marked as NOT NULL during initdb. Shouldn't it be?
> At some point, I inferred a rule that catalog columns were intended to > be either both fixed-width and not nullable; or variable-width and > nullable. I believe the current situation is the result of that > inference... but I see no particular reason not to change it. The actual rule that's embodied in the bootstrap code is to mark everything that could potentially be referenced via a C struct field as not nullable: which is to say, fixed-width fields up till we get to the first variable-width one. It's fairly likely that this is *not* marking all the columns that the code expects to be non-null in practice. The idea I'm toying with right now is to additionally mark as not nullable any column referenced in a DECLARE_UNIQUE_INDEX command in catalog/indexing.h. But I've not looked through that set carefully; it's conceivable that we actually have some indexed catalog columns that are allowed to be null. A possibly better solution is to invent a new macro that has the same semantics as DECLARE_UNIQUE_INDEX, plus forcing the columns to be marked NOT NULL. A bigger-picture question is whether there are yet more columns that could be marked not null, and how much we care about making them so. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers