Ayende @ Rahien

Martin commented on NHibernate new feature: Lazy Properties

Sat, 27 Mar 2010 17:31:26 GMT

btw. i just want to add after having tested it some more, that the proxy works fine (i am able to call the methods on the object) if there is no lazy properties set on the object/proxy. But when a property is set to be lazyloaded, it is not possible to call any methods on the proxy / object being generated.

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Sat, 27 Mar 2010 16:12:39 GMT

Martin, No, it is not a known issue, can you create a JIRA issue for this?

Martin commented on NHibernate new feature: Lazy Properties

Sat, 27 Mar 2010 15:43:04 GMT

Hello again, This is really is a nice feature. Lazyloading a component actually also works with the latest code. But there is a really big show stopper. If i query an object an Castle.Proxies.MyObjectProxy is returned, and it is not possible to call any methods on the MyObject object. The method is never hit. It is like it is overriding the methods and never calls the base method. Is this a know issue ? Martin

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Wed, 03 Mar 2010 12:42:12 GMT

Rasmus, That isn't what Enumerable does, Enumerable is useful if you expect most of your results to reside in the 2nd level cache

Rasmus commented on NHibernate new feature: Lazy Properties

Wed, 03 Mar 2010 07:33:00 GMT

"This is very useful for binary data. However, I'm wondering if there is a way that NHibernate can stream the data? Using something like SqlDataReader for sequential access to varbinaries, rather than pulling all the data at once?" Wouldnt IQuery.Enumerable combined with Session.Evict let you do something like this. The manual 14.5 says: "Whenever you pass an object to Save(), Update() or SaveOrUpdate() and whenever you retrieve an object using Load(), Find(), Enumerable(), or Filter(), that object is added to the internal cache of the ISession. When Flush() is subsequently called, the state of that object will be synchronized with the database. If you do not want this synchronization to occur or if you are processing a huge number of objects and need to manage memory efficiently, the Evict() method may be used to remove the object and its collections from the cache. IEnumerable cats = sess.Enumerable("from Eg.Cat as cat"); //a huge result set foreach( Cat cat in cats ) { DoSomethingWithACat(cat); sess.Evict(cat); } "

Martin commented on NHibernate new feature: Lazy Properties

Mon, 01 Mar 2010 23:36:54 GMT

Thanks, i have just opened one. I filed it under Bug, but it might actually be a New Feature depending on if it should be possible.

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Mon, 01 Mar 2010 22:26:10 GMT

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Ayende Rahien commented on NHibernate new feature: Lazy Properties

Mon, 01 Mar 2010 21:53:46 GMT

Please open a JIRA issue

Martin commented on NHibernate new feature: Lazy Properties

Mon, 01 Mar 2010 21:50:43 GMT

Thanks for the quick reply. It is possible to set lazy=true but it isnt working, that is why i am wondering if it actually should work. :)

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Mon, 01 Mar 2010 19:58:41 GMT

Martin, I don't _think_, but I haven't checked. You can try :-)

Martin commented on NHibernate new feature: Lazy Properties

Mon, 01 Mar 2010 14:54:14 GMT

Ayende: Is it possible to mark a Component to be lazyload ? So if any of the properties in the component is accessed all properties in the component is loaded ?

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Thu, 28 Jan 2010 20:02:40 GMT

lpodolak, Separate them to a different table, that is my suggestion

lpodolak commented on NHibernate new feature: Lazy Properties

Thu, 28 Jan 2010 19:52:00 GMT

"As usual, be cautious in over using it.". I can only think of this as a way to prevent some blobs and clobs fetched when we don't need them. But doesn't it lead to the point that we should separate blob and clobs in our storage (as keeping them in separate tables)? Keeping the Post.Image together as an business entity would make sense due to consistency with customer's language, However in database, it wouldn't be that necessare to keep image in the Posts table. Which approach do you recommend and why?

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Thu, 28 Jan 2010 16:36:20 GMT

Ssidhu, No, if you want a stream, you need to do provide a Stream property and a IUserType implementation

SS commented on NHibernate new feature: Lazy Properties

Thu, 28 Jan 2010 16:08:16 GMT

This is very useful for binary data. However, I'm wondering if there is a way that NHibernate can stream the data? Using something like SqlDataReader for sequential access to varbinaries, rather than pulling all the data at once?

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Thu, 28 Jan 2010 15:41:15 GMT

Configurator, No, you can't. To be rather more exact, you won't know when NH is doing it and when some other code is. Your code would work, however.

configurator commented on NHibernate new feature: Lazy Properties

Thu, 28 Jan 2010 15:34:50 GMT

I like this idea. Can I use the property setter as a way to know when the lazy property is fetched? Can I assume it will only happen once (except when I set the property myself)? public string Text { get { return text; } set { text = value; DoLongOperationToPrepareTextForDisplay(); } }

Thilak Nathen commented on NHibernate new feature: Lazy Properties

Thu, 28 Jan 2010 09:49:30 GMT

Something still smells about the whole deal.

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 23:13:38 GMT

Edin, Two reasons: a) it isn't implemented in hibernate b) having two stage load is usually enough, while you can make arguments that it would be nice to have multiple fetch groups, the problem is that you then start making things so much harder on a lot of levels. Just deciding what should go where would be hard enough, then you have the complexity of multiple fetch groups in a single entity, the possibility of loading an entity goes from a select or to to M selects, where M is the number of fetch groups.

Edin commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 21:56:14 GMT

Very nice feature indeed. But, in case of multiple lazy properties, why isn't it possible to load only one lazy property when accessed ? I do however agree on advice of not overusing this feature.

Nasty Nitpicker commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 19:22:44 GMT

I see, playing Humpty Dumpty?

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 19:16:53 GMT

Nitpicker, I call it select n+1.

Nasty Nitpicker commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 19:15:15 GMT

Just a small nitpick as I see this in your posts all the time: it's not "SELECT N+1", that's nonsense. The right expression is "the N+1 SELECTs problem".

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 14:33:14 GMT

Ivos, No, not at the moment.

ivos commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 14:20:23 GMT

Really nice and expected feature! Could batch be configured for lazy properties?

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 14:04:27 GMT

David, No, it _will_ work, but you must ensure that you never actually access the field directly.

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 14:03:50 GMT

Thilak, The problem is that it violates one of POCOness, it you need to use NHibernate's types to handle that. The entity should be aware of its loaded status, either. Having auto props means that this is basically transparent, and my solution for your dillema would be protected virtual string TextInternal {get;set;} public virtual string Text { get { return Text; } set { Text = value; } You can certainly extend the support for this in NH, of course, if you really care that much about Bytecode weaving means that you need a post compile step, and that it something we would like to avoid

David commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 14:01:12 GMT

"What this means is that if you mark a property as lazy, it must be a virtual automatic property." Does that mean this won't work for VB code except in VS2010?

Thilak Nathen commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 13:56:36 GMT

I get the interception dilemma... but what's wrong with private IMyLazyLoadedProperty

Ayende Rahien commented on NHibernate new feature: Lazy Properties

Wed, 27 Jan 2010 13:38:00 GMT

Thilak, The reason for that is quite simple, we need to intercept the access. The other option is bytecode weaving, and we don't want to do this by default