On Fri, 22 Aug 2008 08:48:30 +0200 Alban Hertroys <dalroi@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > Is it going to make things faster if I: > > > > delete from s; > > reindex table s; > Why do you think this step would help you any? There's no index on > p to begin with. You'd just be reindexing the auto-generated > unique index on s (due to it being a PK). Sorry I forgot to add the index in the example. What if there was an index in s.pid too? But mostly... if I delete s will the deletion of p be faster? > > delete from p; > And no, this would most likely be slower. Why? Stopping a delete from p; I can see that actually postgresql is also executing a delete from s where pid=$1; if s is already empty, and there are no other cascading delete on s, the lookup should be faster. I was wondering if that doesn't make a difference in terms of performance if a) I've an index on pid on both tables or b) s is already empty and... should I reindex s if I "delete from s" first if I want some speed up on delete from p; Anyway this looks more and more a dead end once things get more and more complicated since it requires too much bookkeeping. -- Ivan Sergio Borgonovo http://www.webthatworks.it
