DROP TABLE "SYSTEM"."attrep_changesDAOC7DA_0000155" [1020403] ORA-14452: attempt to create, alter or drop an index on temporary table already in use [

[iucv]

When I checked my cdc tasks, I found that none of them were synchronized in real time. So I started to check the log, which shows "Failed executing drop table statement: DROP TABLE "SYSTEM"."attrep_changesDAOC7DA_0000155" [1020403] ORA-14452: attempt to create, alter or drop an index on temporary table already in use [1022307]" , So I deleted the session that was using the table in the oracle database, and successfully executed the drop table "SYSTEM"."attrep_changesDAOC7DA_0000155", but in the following period of time, a large number of this error appeared.
Do you guys have a solution to this error?

[john_wang · Accepted solution]

Hello @iucv ,

Thanks for reaching out.

In general this is caused by Oracle connection not stable and the broken connections locked the net change table (like "attrep_changesDAOC7DA_0000155"). As the issue is happening on global temporary tables only, we'd like to suggest you to disable the use of global temporary table  by adding an internal parameter createNetChangesTempTable on target Endpoint:

IF the problem persists please enable target_apply to Trace (or Verbose) and provide the task Diagnostics Packages (opening a support ticket, please do not attach them here as community is public), support team will help you to investigate further.

Hope this helps.

Regards,

John.

[iucv]

This is an effective solution and it did solve the problem for me with such configuration. However, its impact on performance is significant, which led me to replace the machine of the target database and optimize the stability of the database connection.

[iucv]

Also, I greatly appreciate your answer. It gave me the right direction.

[KellyHobson]

Setting internal parameter createNetChangesTempTable = False 

Provides the desired workaround, but we recommend identifying the network drops causing these issues. The root cause is network not stable, make sure the network works fine then we may set it back to TRUE.

createNetChangesTempTable = True or enabled is the Oracle Target setting by default.

[R2JOE]

Hello, I have the same problem. Could you please advise me on how to optimize the stability of the Oracle connection?
Thank you!

[john_wang]

Hello @R2JOE ,

Does the option mentioned above not work in your case? Could you please elaborate on the issue or clarify your question?

Thank you.

John.

[jameswalker]

This error usually means another session or background process is still holding the temporary table when the CDC task tries to drop it. Restarting the affected CDC task or the replication service often clears those stuck sessions cleanly. It’s also a good idea to check for any orphaned Oracle sessions before the task runs. Make sure your CDC tool is on a supported version and that any recommended patches are applied. If the issue keeps repeating, it may be a known bug, and reaching out to vendor support is usually the best next step. Regularly reviewing logs from a central website or dashboard, similar to setups discussed on Neefox, can help catch this early.