H2 Database multiple connections

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Dirk picture Dirk · Sep 13, 2012 · Viewed 23.1k times · Source

I have the following issue: Two instances of an application on two different systems should share a small database. The main problem is that both systems can only exchange data through a network-folder. I don't have the possibilty to setup a database-server somewhere.

Is it possible to place a H2 database on the network-folder and let both instances connect to the database (also concurrently)?

I could connect with both instances to the db using the embedded mode if I disable the file-locking, right? The instances can perfom either READ or INSERT operations on the db. Do I risk data corruptions using multiple concurrent embedded connections?

Answer

Ahmet DAL picture Ahmet DAL · Nov 25, 2014

I had the same issue and I've found the solution in the documentation. It can be found at; http://h2database.com/html/features.html#auto_mixed_mode

Multiple processes can access the same database without having to start the server manually. To do that, append ;AUTO_SERVER=TRUE to the database URL. You can use the same database URL independent of whether the database is already open or not. This feature doesn't work with in-memory databases.

// Application 1:
DriverManager.getConnection("jdbc:h2:/data/test;AUTO_SERVER=TRUE");

// Application 2:
DriverManager.getConnection("jdbc:h2:/data/test;AUTO_SERVER=TRUE");