Hi, I am developing an application in which a variety of data is stored in an H2 database. This data includes some image files and (potentially) large blocks of text. The application uses a client/server architecture so that it can be used with a local database or connect to a server using RMI. The interface of the server is the same regardless of whether the server is local or remote. When the server is local the application instantiates the server in the same JVM and the server connects to the H2 database with an embedded connection. When the server is remote it is a separate application, containing an embedded H2 database, that multiple clients can connect to via RMI. The local and remote servers share a lot of functionality so they both inherit from an abstract server class, the remote server contains extra stuff to handle multiple users and network streaming. I am using RMIIO to stream data to and from the remote server, which means it is easiest to store text in BLOBS since RMIIO does not wrap Readers.
In the remote server I am using a connection pool to access H2. A connection is established per client so that they can maintain separate transactions. I would like to be able to stream data while executing other queries as the same user, mainly in order to retrieve images from the database in the background. I am not sure how this works in terms of transactions. If I execute a query to retrieve a BLOB and obtain an InputStream by called ResultSet.getBinaryStream(), when does the table get locked and unlocked? Should I create a DB connection for the stream and not commit the transaction until the stream has been closed? I want to eliminate the possibility of the BLOB being modified or deleted by another DB connection while it is being read. If I haven't provided sufficient information, please let me know. Matt -- You received this message because you are subscribed to the Google Groups "H2 Database" group. To view this discussion on the web visit https://groups.google.com/d/msg/h2-database/-/L_0mQ4VfQlwJ. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/h2-database?hl=en.
