Read consistency? - errr.........

Hi Again,

Gandolf - the conversation is not necessarily 'silly'. It was an anomaly I discovered, and here we are discussing why it occurs. I never said it was affecting a production environment.

Here's a very interesting thread from Ask Tom:

http://asktom.oracle.com/pls/ask/f?p...A:839412906735


So, I was surprised to see that a 'truncate' actually drops the object, then recreates it. I was under the impression that 'truncate' just moves the highwater back down to zero??

Yes, surprising too that the dependant objects don't become invalid.

Quote:

---

Originally posted by DaPi
Yes, surprising too that the dependant objects don't become invalid.

---

Looks like Oracle would compile such objects ..

Quote:

---

Originally posted by Horace

Here's a very interesting thread from Ask Tom:

http://asktom.oracle.com/pls/ask/f?p...A:839412906735


So, I was surprised to see that a 'truncate' actually drops the object, then recreates it. I was under the impression that 'truncate' just moves the highwater back down to zero??

---

I don't think that is meant literally (especially where the "reuse storage" clause is invoked)-- Oracle would potentially have to recreate a lot of other stuff as well. I asked a follow on question to get clarification.

Thanks Dave,

Followed your follow up!!

Looks like drop and re-creating. See the below test.

Code:

---

SQL> select object_id,data_object_id from user_objects where object_name='X';

 OBJECT_ID DATA_OBJECT_ID
---------- --------------
      6117          6121

SQL> truncate table x;

Table truncated.

SQL> select object_id,data_object_id from user_objects where object_name='X';

 OBJECT_ID DATA_OBJECT_ID
---------- --------------
      6117          6122

SQL> create table c ( a number);

Table created.

SQL> select object_id,data_object_id from user_objects where object_name='C';

 OBJECT_ID DATA_OBJECT_ID
---------- --------------
      6123          6123

SQL> truncate table x;

Table truncated.

SQL> select object_id,data_object_id from user_objects where object_name='X';

 OBJECT_ID DATA_OBJECT_ID
---------- --------------
      6117          6124

---

My last OBJECT_ID was 6117 and many truncates untill 6123. Then I re-created another table which took object_id as 6124 next to 6123 means OBJECT_ID and DATA_OBJECT_ID is using the same sequence and is not different. Something really new!