Blobs in hsqldb with "res" connection string - blob

Question

I have a hsqldb database packaged in, a jar file that contains my database files (mydb.script and mydb.lobs).
When connecting to my database using "res" url (jdbc:hsqldb:res:mydb) all the queries work ok except getting bytes from a BLOB column. This is the exception I get:
Caused by: org.hsqldb.HsqlException: file input/output error
at org.hsqldb.error.Error.error(Unknown Source)
at org.hsqldb.types.BlobDataID.getBytes(Unknown Source)
at org.hsqldb.types.BlobInputStream.readIntoBuffer(Unknown Source)
When connecting to the same database using "file" url everything works. The code used to get bytes from a BLOB column is this:
// rs is ResultSet
Blob blob = rs.getBlob(i + 1);
int blobSize = (int) blob.length();
byte[] bytes = new byte[blobSize];
InputStream is = blob.getBinaryStream();
try {
is.read(bytes, 0, blobSize);
} catch (IOException e) {
logger.error("Error reading bytes from blob: ", e);
}
Any ideas what could cause reading bytes from BLOB column to fail when using "res" url and succeed when using "file" url?

Answer 1

With databases used as resources (in the class path or jars) LOBs are not supported in HSQLDB up to version 2.2.9. The next version should support it.
Initial support has just been added to the latest HSQLDB snapshot jar which can be downloaded from:
http://www.hsqldb.org/repos/org/hsqldb/hsqldb/SNAPSHOT/