Hang after DDL command

some times toad hangs after running DDL command


Hi "zmallah",

This is entirely possible. If you attempt to, for example, ALTER TABLE while that table is currently involved in a transaction involving DELETE, INSERT or UPDATE, then Oracle will have taken out a TM lock on the table as well as a TX lock for the DML transaction. This stops the table from being changed while there are active transactions against it.

Any session attempting DDL on that table will hang until aborted or until the transactions against the table are all committed or rolled back. Only then will the DDL will be carried out.

If, while waiting to get the table for the DDL, other sessions start new DML transactions, then your DDL waiting session will be put to the back end of the queue - and wait a bit longer.

If you configure Toad to run queries in separate threads, when the DDL hangs, use the session browser and check for blocking locks.


Norm. [TeamT]