What is the difference between Truncate and Delete? Why is one faster?
Can we ROLLBACK both? How would a full table scan behave after?
Submitted by: AdministratorTruncate is nearly instantaenous, cannot be rolled back, and is fast because Oracle simply resets the HWM. When a full table scan is performed on a table, such as for a sort operation, Oracle reads to the HWM. So if you delete every single solitary row in 10 million row table so it is now empty, sorting on that table of 0 rows would still be extremely slow.
Submitted by: Administrator
Submitted by: Administrator
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