On Thu, Nov 12, 2015 at 4:26 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > Merlin Moncure <mmoncure@xxxxxxxxx> writes: >> On Thu, Nov 12, 2015 at 9:48 AM, Craig James <cjames@xxxxxxxxxxxxxx> wrote: >>> What about a warning on creation? >>> >>> db=> create table foo(i integer primary key); >>> db=> create table bar(j integer primary key, i integer); >>> db=> alter table bar add constraint fk_bar foreign key(i) references foo(i); >>> WARNING: fk_bar: column bar(i) has no index, deletions on table foo may be >>> slow. >>> >>> It might save some fraction of these questions. > >> Maybe, but I wonder if this would cause pg_restore to bleat warnings >> when restoring. > > We could probably teach pg_dump to put index definitions before FKs, if it > doesn't already. But I'm suspicious of this sort of "training wheels" > warning --- we've had roughly similar messages in the past and removed > them because too many people complained about them. For posterity, indexes are the last step -- and I think that's a good way to do things. As to the broader point, I agree. Warnings should be reserved for things that are demonstrably dubious, and there are just too many situations where that doesn't apply for an unindexed foreign constraint. Oh well. merlin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
