建议修改为由应用程序调用的文件，然后用stream 打开，性能调高50倍。
到了11g Oracle 新功能 SecureFiles 可以解决LOB 的性能问题，又能充分兼容LOB 的特性。
此功能能否和介绍的那么好需要等客户验证。
下面是Oracle 的介绍：
?SecureFiles breaks the performance barrier that has
kept file data out of databases
?Similar to LOBs but much faster,
and with more capabilities
?Transparent
encryption (with Advanced Security Option)
?Compression,
Deduplication (with Advanced Compression Option)
?Superset
of LOB interfaces for easy migration from LOBs
?Benefits
?Single
security model
?Single
view of data
?Single
management of data
?High
performance