Is there any limitation for data engine to hold large number of queues(in size as well?).
No, Actually the Limitation is your DB Performance/Sizing.
As a Best Practice please check:
If your DB is SQL Server:
If is Oracle or MySQL Please check the documents attached.
Sreenathmp could you please confirm if your question was answered in the last update, if yes, please mark it ar correct/answered, if you still have doubt about the same subject, please let us know!