On 11/10/14, 12:00 PM, Simon Riggs wrote:
On 10 November 2014 17:33, Alvaro Herrera <alvhe...@2ndquadrant.com> wrote:
pg_dump --no-revalidaton
will add "NOT VALID" onto the recreation SQL for any FKs, but only for
ones that were already known to be valid.
Well. Constraints that haven't been validated already have a NOT VALID
emitted by ruleutils.c, yes? So what this patch does is add such a
clause for all *other* constraints. Right? In other words what it aims
to do is speed up loading of data by skipping the validation step on
restore. Is that right?
Correct. CHECK constraints are added onto main table so they validate at load.
ISTM we could have the default pg_dump behavior emit NOT VALID
constraints, and add VALIDATE CONSTRAINT commands at the end; that way
the database is usable sooner but the constraints end up marked as
validated by the time the dump is finished.
Yes, may be an even better idea. We'd still want the --no-revalidation
option, AFAICS.
FKs are already "at the end". Perhaps we should add another
"validation" section?
I like the idea, just not sure how long it would take.
Isn't the real use-case here that if constraints were valid when you dumped
then we shouldn't have to *any* re-validate when we load? (Though, we'd have to
be careful of that with CHECK because that can call user code...)
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com
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