[20130609]ORA_HASH and LOBs.txt

http://connormcdonald.wordpress.com/2013/03/29/ora_hash-and-lobs-not-nice-partners/

参考以上链接,重复测试:

create table t (a number,b varchar2(20),c clob);
insert into t values (1,'a','a');
commit ;

SQL> select ora_hash(b),ora_hash(c) from t;

ORA_HASH(B) ORA_HASH(C)

----------- -----------

   29220167  2365849875


--sleep 3s


SQL> select ora_hash(b),ora_hash(c) from t;

ORA_HASH(B) ORA_HASH(C)

----------- -----------

   29220167   892983579


--sleep 3s

SQL> select ora_hash(b),ora_hash(c) from t;

ORA_HASH(B) ORA_HASH(C)

----------- -----------

   29220167  3168263238

It changes ! In fact, one most platforms it appears to change every 3 seconds, so presumably somewhere in there its
related to one the internal Oracle timers in some way.

ITPub博客

[20130609]ORA_HASH and LOBs.txt

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