Nickolay,

> But you need to have transaction that is explicitly read-committed and
> isc_tpb_read - read-only (in this case transaction is started as
> pre-committed and may not be committed without impact on the engine) !
> Otherwise you are going to inhibit garbage collection and may loose
> performance.

Thanks for pointing this out. In terms of JDBC this would be:

connection.setTransactionIsolation(
Connection.TRANSACTION_READ_COMMITTED);
connection.setReadOnly(true);

Best regards,
Roman Rokytskyy