Question about solution - Access to database. Hibernate? iBatis? or what?

my project has a lot of time restrictions on access to functionality. Layer view, I have a very fast, but I have a problem with DAO layer. Currently my DAO layer uses hibernate. But I noticed that I had with him a lot of problems and I can not modify it so that any optimization mechanisms use to database.

In my database there are about 20 million users in relation to the tables where there are thousands of tuples. Tables are partitioned for faster access.

I wonder what framework to use instead of hibernate. I thought about using iBatis. I want t开发者_如何学JAVAo know about you think about this idea? Is iBatis will allow me to tune queries / updates in order to make efficient use of such a large database? Can I full use partitioned database?

Can you recommend any other solutions?

BD: Oracle.

Thanks for any help.

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use Ibatis, you could do query optimizing much much better than in hibernate, and the most important is separation of sql queries from the DAO Codes.

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You should be able to improve Hibernate performance or query performance in Hibernate. Could you elaborate more on where your problems and restrictions are? Could you post some code?