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Question and Answer

Connor McDonald

Thanks for the question, lin.

Asked: October 29, 2017 - 7:55 am UTC

Last updated: October 31, 2017 - 8:09 am UTC

Version: 11.2.0

Viewed 1000+ times

You Asked

Hello Tom

According to
https://docs.oracle.com/database/121/ADLOB/adlob_smart.htm#ADLOB46175

basicfile lob must be stored in a tablespace with segment space manually managed. However, it seems oracle does not prevent user from creating it in an ASSM tablespace:


SQL> select tablespace_name,segment_space_management from dba_tablespaces where tablespace_name = 'AUTOTS';

TABLESPACE_NAME SEGMEN
------------------------------ ------
AUTOTS AUTO


SQL> create table testlob1 (
ID number,
DATA CLOB
) tablespace users
lob(data) store as basicfile (
tablespace autots
);

Table created.

So is there any reason basicfile LOB should not be used with ASSM?

and Connor said...

You're mis-reading it slightly.

"You must use BasicFiles LOB storage for LOB storage in tablespaces that are not managed with Automatic Segment Space Management (ASSM)."

ie

*IF* you have a tablespace that is not managed with Automatic Segment Space Management (ASSM) ... *THEN* you must use a BasicFile.


Make sense ?

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Comments

Non à clear response please details

Gus, October 30, 2017 - 7:24 am UTC

So for instance our tablespaces are all assm.
And all our tables lobs are basicfiles. what's the
Problem?
Connor McDonald
October 30, 2017 - 9:55 am UTC

Let me repeat:


*IF* you have a tablespace that is *not* managed with Automatic Segment Space Management (ASSM) ...

*THEN* you must use a BasicFile not a Securefile.

Non à clear response please details

Gus, October 31, 2017 - 5:53 am UTC

Could have another answer from another source please. My question still the same above. We have only assm tablespaces for business tables and all lobs are created as basicfiles. So what could be the problem as we didn't encountered nothing.

Non à clear response please details

Gus, October 31, 2017 - 5:58 am UTC

So I understand that only securefiles are to be used within assm tbs
And basicfiles could be used within both.
If so that s the expected answer instead of repeating the same confusing one
Connor McDonald
October 31, 2017 - 8:09 am UTC


Now lets walk through *my* statement... step by step.

Step 1:

"*IF* you have a tablespace that is NOT managed with Automatic Segment Space Management (ASSM)..."

Now - what were your first 5 words...

"We have only assm tablespaces..."

So.... do you have "a tablespace that is NOT managed by ASSM" ???

No... you don't.


Step 2:

There *is* no step 2... because you don't have a tablespace that is NOT managed by ASSM.

Seems pretty clear to me.




Jeff, October 31, 2017 - 1:41 pm UTC

"So I understand that only securefiles are to be used within assm tbs"
Gus, that is not a correct statement. Your "only" is in the wrong place. It should read "securefiles are to be used only within ASSM tbs".

Basicfiles can be used in either ASSM or non-ASSM tablespaces.

Securefiles cannot be used in non-ASSM tablespaces.

Thkz

Gus, October 31, 2017 - 7:12 pm UTC

The five stars are for Jeff.
But sure thanks for Connor and Jeff.

A reader, November 01, 2017 - 8:52 am UTC

I misread the doc. The feedback from Tom is clear. Thanks!

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