ORA-30027: Undo quota violation

I have a 11204 database where I am seeing ORA-30027: Undo quota violation - failed to get 100 (bytes) , error in application logs.

My understanding tells me that such errors occurs only during DML's statements but in my case the error is happening during CREATE table and create index's statements. Is this normal ?

Every time I used to increase undo quota which resolved the problem for time being but error kept on coming after few days.

I have checked if undo_pool had any value set but I don't see any value which means it has been allocated unlimited value.

Can someone provide some recommendations on what should I look at as why it's happening during DDL's and how to resolve the error (apart from increasing undo quota every time)

Regards,
Arpit

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