Ivan Sergio Borgonovo wrote: > On Fri, 20 Feb 2009 06:50:22 -0800 > David Fetter <david@xxxxxxxxxx> wrote: >>> ... moving some of the checks >>> into the database and away from the application. >> Since a useful database has *many* applications instead of "the" >> application, I think this is an excellent move. > > ....I was wondering if "checks" may have an impact > on performances and if pg does some optimisation over them. Are you suggesting thee would be a positive or negative impact on performance. Moving some checks in the database should *improve* performance by giving the planner improved information. For example, unique constraints indicate when only 0-1 rows may come out of a query; and range constraints could let a database know when a partition doesn't even need to be visited. No doubt other checks (say, spellchecking a column) would have have performance costs. I'm with David Fetter's perspective of considering multiple applications that can run on top of a database. If a particular check should apply to all conceivable applications that run on a database (say, foreign key constraints) it seems to me they belong in a database. If a particular check should apply to just one application, but other applications might have reasons not to enforce such a check (say, one app might do spell checking in english; another in a different language) - that belongs in the app. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
