IdentityMap feature for Active Record

Archives Feature Requests
1

Rails has recently introduced an identity map feature that ensures that models are loaded only once in a request. This is really useful to maintain consistency, it means you never get multiple instances of the same model floating around in the same request, so it can save a lot of resources if used properly.

I’ve added a quick implementation here:

It’d be really nice to have this in the core (although it should be disabled by default). I already opened a feature request for it, but I don’t think Qiang sees the advantages of it yet. Does anyone else have any thoughts on the matter?

2

And the issue for this is on this link - http://code.google.c…tail?id=2817#c0

3

Is there any chance this is going to be reconsidered for Yii 2.0? A similar issue has been closed, stating that Yii now supports query caching. But I think query caching solves other problems than an identity map does.

4

When we’ll show Yii2 code to community you’ll be able to test memory consumption to determine if it is necessary.

5

Yes, certainly. But this doesn’t really answer my question :rolleyes: I take it IMs are open for discussion again?

6

What’s “IMs”?

7

Identity Maps?

8

Yes, why not.

9

I don’t think the biggest advantage of IM’s are memory onces.

It’s the fact that you could be overwriting yourself several times in an app and that this could be a “very hard to debug”-bug that happens occasionally and you might never know about it.