Originally posted by tamilselvan
The maximum number of bytes allowed in a column for an index to be created is 3209 in 8i.
It is not that simple (besides, the size provided above is not correct anyhow).

The maximum allowed index key length depends on your block size. So the mixumum allowed size reported in ORA-01450 varies, depending on which block size your index is using:

ORA-01450 maximum key length (758) exceeded ->(2K Block)
ORA-01450 maximum key length (1578) exceeded ->(4K block)
ORA-01450 maximum key length (3218) exceeded ->(8K Block)
ORA-01450 maximum key length (6498) exceeded ->(16K Block)

The numbers in parenthesis represent the maximum index key length for that specific block size. Actually, even those numbers are not the theoretical upper limit, because they are calculated based on the default values of PCTFREE and INITRANS. So in theory you could "squeeze" a couple of additional bytes for max key length by reducing the values of PCTFREE and INITRANS below their defaults.

If anybody is interested in how the maximum index key length is computed, there is a document (Doc.Id 136158.1) on Metalink that explains this in details.