Jon, My point was that SQL optimizations are much easier to implement (I use Oracle too) without an inheritance hierarchy, since EOF is less involved in building queries to handle the structure. I actually have a situation today where I regret using 2 levels of inheritance because I cannot tune the queries as needed, causing a significant degradation of performance. This is especially true with 2 level hierarchies and batch faulting. EOF is just unable to resolve the super-entities correctly. When I tested changing it to a one level hierarchy, performance increased a thousand fold.
In any case, best of luck! Ken On Mar 22, 2011, at 11:04 PM, Jon Nolan wrote: > Hi Ken, > > The inheritance is absolutely necessary and works a treat. My example EO > tree is just that, an example for the sake of simplicity. The real model > supports social network content types and is fairly esoteric (the example is > easy to understand and is a valid representation). While quite complicated > our model supports our needs almost perfectly. The differences in behavior > between types can be substantial. > > The behavior of the objects and the structure of the model isn't the problem. > The problem is very much localized to data retrieval speed and is more an > Oracle issue than a Web Objects one. I'm trying to optimize it in various > ways - some on the WO side and others on the DB side. I'm not considering > throwing away the substantial benefits of our model design. > > The specific behavior I'm looking for is influencing Oracle's optimizer to > NOT do full table scans when retrieving these objects. Getting rid of big OR > qualifiers, controlling the order of restricting v. non-restricting > qualifiers, utilizing hints, using views, etc. All in play. > > Thanks, > Jon > > > > On 3/22/11 8:18 PM, Ken Anderson wrote: >> Not to put a crimp in your model, but is inheritance really necessary here? >> What actual behavior is different? >> >> One level inheritance is hard to optimize - two levels, doubly so (at >> least!). If you could share more about what kind of behavior you're looking >> for from these objects it might be helpful to everyone on the list. >> >> Ken >> >> On Mar 22, 2011, at 7:31 PM, Jon Nolan wrote: >> >>> I have a fairly involved EO inheritance tree that works beautifully in >>> every way but one. Here's a quick example illustrating the structure I'm >>> using: >>> >>> Human >>> North American >>> American >>> Canadian >>> Mexican >>> European >>> German >>> Italian >>> Spaniard >>> Asian >>> Korean >>> Laotian >>> >>> etc. You get the idea. >>> >>> So if I utilize European.fetchEuropeans(...) a qualifier is generated along >>> the lines of HUMAN_TYPE = German or HUMAN_TYPE = Italian or HUMAN_TYPE = >>> Spaniard. This would be fine except for the Oracle optimizer deciding not >>> to use the HUMAN_TYPE_IDX index. I've tried using hints but (a) it's >>> difficult to get right for a query generated by a ERXBatchingDisplayGroup >>> and (b) the JDBC adaptor disconnects me when I try. >>> >>> There is another qualifier clause which happens to make it so that, in the >>> European example, all the returned humans will indeed be German, Italian or >>> Spaniard. Is there any way to simply discard the OR'd HUMAN_TYPE >>> qualifier? Any other suggestions? Do I have something wrong in my model >>> in the first place? >>> >>> Thanks, >>> Jon >>> _______________________________________________ >>> Do not post admin requests to the list. They will be ignored. >>> Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) >>> Help/Unsubscribe/Update your Subscription: >>> http://lists.apple.com/mailman/options/webobjects-dev/kenlists%40anderhome.com >>> >>> This email sent to kenli...@anderhome.com >> >> > _______________________________________________ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
