Recently a discussion was ongoing on the oracle-L list about the question if a select could block a truncate or not.
The first reaction that I had was that, when a select would be active reading from a table, the truncate would fail with the message: “resource busy and acquire with NOWAIT specified”. My reasoning behind this was that a truncate is a ddl statement, which generates no undo for the “deleted” records. So to guarantee that the select would be read consistent, Oracle would have to fail the truncate.
But when discussing this at the office, my colleague Geert claimed that a select placed no protection on the structure of a table and that it would be the select statement that would fail (with the message that the object does no longer exists).
At these moments, there is only 1 thing that you can realy do, and that is to test it. So I did and I found out that is not so strait forward.
Here we go:
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