Re: ALTER TABLE ADD COLUMN fast default

Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com> writes:
> On Wed, Mar 28, 2018 at 5:30 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
>> + /*
>> + * Missing value for added columns. This is a one element array which lets
>> + * us store a value of the attribute type here.
>> + */
>> + anyarray attmissingval BKI_DEFAULT(_null_);
>> #endif
>> } FormData_pg_attribute;
>>
>> Still think this is a bad location, and it'll reduce cache hit ratio for
>> catalog lookups.

> As I think I mentioned before, this was discussed previously and as I
> understood it this was the consensus location for it.

I don't have a problem with putting that in pg_attribute (and I certainly
agree with not putting it in pg_attrdef). But "anyarray" seems like a
damn strange, and bulky, choice. Why not just make it a bytea holding the
bits for the value, nothing more?

regards, tom lane