Migrating from H2 to mySQL

[Tariq Mehmood]

Hi all,

I recently did a data transfer from H2 to mySql.

1. I copied all the tables from H2 using a bash script
2. Converted them into .csc files(each table has a .csv file)
3. Ran mysqlimport command to dump these .csv files into MySQL database(data transfer to MySQL was successful, it is skipping some records in some of the tables, which i believe because of relationships)
4. Gerrit is starting OK
5. First user was created in MySQL table and given administrative rights.

I cannot see all the repos in Gerrit.

Error log is as follows:Thanks for the reply,

the error log looks like this in my case:

[2012-08-15 11:46:33,637] WARN  / : Error in allQueryNext

java.lang.IllegalStateException: Missing project All-Projects

    at com.google.gerrit.server.project.ProjectCacheImpl.getAllProjects(ProjectCacheImpl.java:90)

    at com.google.gerrit.server.account.CapabilityControl.<init>(CapabilityControl.java:55)

    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)

    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)

    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)

    at com.google.inject.internal.DefaultConstructionProxyFactory$2.newInstance(DefaultConstructionProxyFactory.java:85)

    at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:85)

    at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:254)

    at com.google.inject.internal.InjectorImpl$4$1.call(InjectorImpl.java:978)

    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1024)

    at com.google.inject.internal.InjectorImpl$4.get(InjectorImpl.java:974)

    at com.google.inject.assistedinject.FactoryProvider2.invoke(FactoryProvider2.java:632)

    at $Proxy35.create(Unknown Source)

Any thoughts/pointer are welcome and Thanks in advance for your help.

Althought iam getting Application error in the browser but it is authenticating the user which was created when i hit continue.

Tariq

[Robin]

Hi,

probably you are inserting your Data in a wrong order? Like you want to create data with a foreign key, but the linked data doesn't exist?

So you should start with all Tables, that don't have any dependencies. If this is not possible for you, I think there is a so called batch mode or something (Do a research if you need it), with this mode you can insert your data and the dependencies will be checked after the whole batch is finished.

With best Regards 

[Tariq Mehmood]

Hi, Robin;

Thanks for the reply, i finally got rid of this error by reinitializing the gerrit server.

I donot see this error.

Now i am trying to verify the data i imported from H2.

Is there any easy way to verify that all the data was inserted correctly.

BR Tariq

and thanks again for looking into it.

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[Robin]

Hi Tariq,

from my point of view, if everything works fine now, you shouldn't care about the error any more ;).

What I was trying to point out:

If you are migrating your data, it is important to insert at first the tables without any foreign keys. Then while(tables  left){ insert all tables that have only already created foreign tables). And if this algorithm ends up in an endless loop, you should try a batch insert mode (probably batch insert will be allways better?).

Greets Robin

[Tariq Mehmood]

Thanks,

Way i did it was that i created .csv files of each table from H2 and inserted them into to mySQL.

What do u think is this approach fine.

Or will i loose the relationships this way.

Seems you option of batch mode is better but have to research on this one know.

To view this discussion on the web visit https://groups.google.com/d/msg/h2-database/-/NP5KEZdNaOMJ.

[Robin Boldt]

Hi,

if the insertion worked without any warnings or errors, the migration should have been successful ;)

2012/8/16 Tariq Mehmood <tari...@gmail.com>

[Tariq Mehmood]

Hi, 

Yep there were no errors or warnings just few records skipped.

Still need to figure out why its skipping those records..................

I think that is because of mySQL handles relationships differently than H2.