Jeff Janes <jeff.janes@xxxxxxxxx> writes: > I've been plagued several times by NOT DEFERRABLE constraints. Is there > any good reason to define a constraint as NOT DEFERRABLE rather > than DEFERRABLE INITIALLY IMMEDIATE? For example, is there performance > penalty for PostgreSQL being prepared to defer a constraint even though it > is not currently being deferred? There's a substantial performance difference between deferrable and nondeferrable uniqueness constraints (ie, indexes). For foreign keys I don't believe it matters. We don't implement deferrability for other types of constraints such as CHECK. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
