Presently LOB types are limited to a size of about 2 GB (2097088000 bytes or characters). Even though the limit is 2 GB, there are times when the LOB size gets twice as large.
The length of a CLOB based on 16-bit character set may get as large as 4 GB. The maximum display size of a BLOB is also 4 GB. To hold a counter of that magnitude (4 GB), an unsigned 32-bit value is required. Use 64-bit integers to accommodate future extensions.
If the character set of a CLOB column is defined with Unicode for its character set, it has a maximum size limit of approximately 1 GB.