MVCC problem with in-memory H2 in 1.4.200

[Björn Schädlich]

Upgrading our project from H2 1.4.199 to 1.4.200, we get an Exception

Caused by:
        org.h2.jdbc.JdbcSQLNonTransientConnectionException: Datenbank-Verbindungs Option "MVCC" nicht unterst³tzt
        Unsupported connection setting "MVCC" [90113-200]

while using JDBC URL

jdbc:h2:mem:backendtests;MVCC=TRUE;MODE=PostgreSQL

I can not believe H2 dropped MCVV support for in-memory DBs, because H2 is first choice for unit tests (JUnit, TestNG) which run backend SQL in in-memory H2 for fast tests, but needs MVCC for several scenarios.

Is this a decision (which would be very sad), or an unwanted bug?

[Björn Schädlich]

Hmm, [1] states that MVStore should support in-memory-usage and MVCC. Perhaps its only a usage problem with correct connection URL params for my case?

[1] http://www.h2database.com/html/mvstore.html?highlight=Mvcc&search=MVCC#inMemory

[Noel Grandin]

Just drop the MVCC param, it will use MVSTore by default, even for in-mem databases, which is naturally an MVCC engine

[Björn Schädlich]

Thank you for your fast reply.

Without the MVCC param, I receive some test failures which I don't get with H2 1.4.199. I'll dive into this and post my results

[Björn Schädlich]

Yeah: Thanks for this great 1.4.200 H2 release:

We had bugs in our tests, which weren't found because of bugs in H2. Now these bugs in H2 are fixed :)

Background: It seems that it could happen in 1.4.199, that being in a schema a select from a table which doesn't exist (being on the wrong schema) could receive a table with the desired name from another schema.

Thanks you very much