When an alter table transaction is triggered from the UI, for example from the Dictionary, and later gets cancelled by the user or a transaction quota rule, all the corresponding triggers and temporary tables are not cleaned from the DB.
The behavior is different when adding a new field to a table, in that case the transaction is not cancellable or does not get cancelled by the quota rule, so the issue does not occur.
Steps to Reproduce
1. Open a fairly large table (>1GB) in the dictionary.
2. Alter a filed in the table by increasing the column length.
3. Wait for the transaction to get cancelled or manually cancel it using 'cancel_my_transaction.do'.
After cancelling the transaction, the 'glide.db.online_alter' threads die off, but the triggers and table are left behind.
This problem is under review and targeted to be fixed in a future release. To receive notifications when more information becomes available, subscribe to this Known Error article by clicking the Subscribe button at the top right of this form.
Related Problem: PRB1269518