On Sat, Aug 15, 2009 at 11:14 AM, harryh <har...@gmail.com> wrote:
>
> > class Foo extends LongKeyedMapper[Foo] with IdPK {
> > def getBazes = {
> > Baz.findAll(In(Baz.barid, Bar.id, By(Bar.fooid, this)))
> > }
>
> OK, upgrading to 1.1-M4 got rid of the NPE so I'm just gonna assume
> there was a bug that has been fixed. However the SQL query that lift
> is generating is no good. It's doing something like this:
>
> SELECT bazes.cityid, bazes.xdatetime, bazes.aliasid, bazes.userid,
> bazes.id FROM bazes WHERE barid IN (SELECT id FROM bars WHERE fooid =
> 22120 );
>
> which is WAY WAY more inefficient than this (by a factor of like
> 100x):
>
> SELECT bazes.cityid, bazes.xdatetime, bazes.aliasid, bazes.userid,
> bazes.id FROM bazes, bars WHERE bazes.barid = bars.id AND bars.fooid =
> 22120;
>
> At least on MySQL (which is what I'm using). Is there any way to get
> Lift to use a query like the latter instead of the former?
No. Lift uses IN ( ) rather than joins. I know that it's fairly recent
that MySQL added nested queries, but I would have thought that they would
have had a reasonable optimizer for them.
>
>
> -harryh
>
> >
>
--
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Git some: http://github.com/dpp
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Lift" group.
To post to this group, send email to liftweb@googlegroups.com
To unsubscribe from this group, send email to
liftweb+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/liftweb?hl=en
-~----------~----~----~----~------~----~------~--~---
