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Surprising Reserch Topic questions - Question:Hibernate faster EntityManagerFactory creation

In my desktop application new databases get opened quite often. I use Hibernate/JPA as an ORM. The problem is, creating the EntityManagerFactory is quite slow, taking about 5-6 Seconds on a fast machine. I know that the EntityManagerFactory is supposed to be heavyweight but this is just too slow for a desktop application where the user expects the new database to be opened quickly.

  1. Can I turn off some EntityManagerFactory features to get an instance faster? Or is it possible to create some of the EntityManagerFactory lazily to speed up cration?

  2. Can I somehow create the EntityManagerFactory object before knowing the database url? I would be happy to turn off all validation for this to be possible.

  3. By doing so, can I pool EntityManagerFactorys for later use?

  4. Any other idea how to create the EntityManagerFactory faster?

Update with more Information and JProfiler profiling

The desktop application can open saved files. Our application document file format constists of 1 SQLite database + and some binary data in a ZIP file. When opening a document, the ZIP gets extracted and the db is opened with Hibernate. The databases all have the same schema, but different data obviously.

It seems that the first time I open a file it takes significantly longer than the following times. I profiled the first and second run with JProfiler and compared the results.

1st Run:

create EMF: 4385ms
    build EMF: 3090ms
    EJB3Configuration configure: 900ms
    EJB3Configuration : 380ms


2nd Run:

create EMF: 1275ms
    build EMF: 970ms
    EJB3Configuration configure: 305ms
    EJB3Configuration : not visible, probably 0ms


In the Call tree comparison you can see that some methods are significantly faster (DatabaseManager. as starting point):

create EMF: -3120ms
    Hibernate create EMF: -3110ms
        EJB3Configuration configure: -595ms
        EJB3Configuration : -380ms
        build EMF: -2120ms
            buildSessionFactory: -1945ms
                secondPassCompile: -425ms
                buildSettings: -346ms
                SessionFactoryImpl.<init>: -1040ms

The Hot spot comparison now has the interesting results:

screenshot compare_hotspot.png.

ClassLoader.loadClass: -1686ms
XMLSchemaFactory.newSchema: -184ms
ClassFile.<init>: -109ms

I am not sure if it is the loading of Hibernate classes or my Entity classes.

A first improvement would be to create an EMF as soon as the application starts just to initialize all necessary classes (I have an empty db file as a prototype already shipped with my Application). @sharakan thank you for your answer, maybe a DeferredConnectionProvider would already be a solution for this problem.

I will try the DeferredConnectionProvider next! But we might be able to speed it up even further. Do you have any more suggestions?


asked Sep 13, 2013 in MYSQL by rajesh
edited Sep 12, 2013
0 votes

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