Best way to handle LOBs in Oracle distributed databases

Question

If you create an Oracle dblink you cannot directly access LOB columns in the target tables.

For instance, you create a dblink with:

create database link TEST_LINK 
  connect to TARGETUSER IDENTIFIED BY password using 'DATABASESID';

After this you can do stuff like:

select column_a, column_b 
from data_user.sample_table@TEST_LINK

Except if the column is a LOB, then you get the error:

ORA-22992: cannot use LOB locators selected from remote tables

This is a documented restriction.

The same page suggests you fetch the values into a local table, but that is... kind of messy:

CREATE TABLE tmp_hello 
AS SELECT column_a 
from data_user.sample_table@TEST_LINK

Any other ideas?

Answer 1

Yeah, it is messy, I can't think of a way to avoid it though.
You could hide some of the messiness from the client by putting the temporary table creation in a stored procedure (and using "execute immediate" to create they table)
One thing you will need to watch out for is left over temporary tables (should something fail half way through a session, before you have had time to clean it up) - you could schedule an oracle job to periodically run and remove any left over tables.