LOBs
It’s worth saying a few words about LOBs since Oracle has some special methods for handling undo and redo on LOBs, and these methods follow through to the handling of transactions and read consistency. If a LOB value has been stored in the row, it is in no way special; it’s just another column. But if a LOB value was stored “out of row” (either because the specific value was too large or because the LOB has been declared with the disable storage in row option), then the LOB data itself is not subject to the normal undo handling and need not be subject to the normal redo handling.
There are variations on the basic theme, but the critical thing to remember with LOB values that have been stored out of row is that you have to access them through ...
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