Re: Support NOT VALID / VALIDATE constraint options for named NOT NULL constraints
| От | Rushabh Lathia |
|---|---|
| Тема | Re: Support NOT VALID / VALIDATE constraint options for named NOT NULL constraints |
| Дата | |
| Msg-id | CAGPqQf2MYSQAdJ11v5b3hqdsOCw=LO_EgbMXwJ41S-+qxA6tZg@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Support NOT VALID / VALIDATE constraint options for named NOT NULL constraints (Peter Eisentraut <peter@eisentraut.org>) |
| Список | pgsql-hackers |
On Thu, Apr 3, 2025 at 8:33 PM Peter Eisentraut <peter@eisentraut.org> wrote:
On 03.04.25 10:07, Alvaro Herrera wrote:
> The new flag is there for quick access by get_relation_info. We could
> easily not have it otherwise, because clients don't need it, but its
> lack would probably make planning measurably slower because it'd have to
> do syscache access for every single not-null constraint to figure out if
> it's valid or not.
In the v6 patch, you are adding a attnullability field to the
CompactAttribute in the tuple descriptor and use that in
get_relation_info(). That seems like the right approach, because then
you're doing all that preprocessing about which constraint is active in
the relcache. So I don't see where the extra pg_attribute field
attnotnullvalid is getting used.'
attnotnullvalid is getting used to populate the CompatAttribute (populate_compact_attribute_internal).
The primary reason for adding a new field to pg_attribute is to avoid the need for an additional scan
of pg_constraint when populating CompatAttribute, as this extra scan introduces performance overhead
while retrieving catalog information for a relation.
Rushabh Lathia
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