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Question and Answer

Connor McDonald

Thanks for the question, Alexander.

Asked: July 13, 2020 - 1:20 pm UTC

Answered by: Connor McDonald - Last updated: July 24, 2020 - 7:37 am UTC

Category: Database Administration - Version: 18c

Viewed 100+ times

You Asked


As it's said
"user data in an Oracle Database XE database cannot exceed 12 gigabytes".

Would You explain how to get exactly that user data size by means of SQL?
Would You also clarify should we add here separate APEX tablespace's size?

Thank You.

and we said...

I don't know the exact algorithm but my understanding is we are basically assume an approximate upper limit on what the base dictionary should be, and taking that into account as to "not counting" toward your limit. We don't base it on what schema/tablespace you use. For example, even if I create objects under the SYS schema, then eventually:

SQL> create table t as select d.* from dba_objects d, ( select 1 from dual connect by level <= 300 );
create table t5 as select d.* from dba_objects d, ( select 1 from dual connect by level <= 300 )
ERROR at line 1:
ORA-12954: The request exceeds the maximum allowed database size of 12 GB.

and I got this error when my SYSTEM tablespace got to 13.1G and my entire database was

SQL> select sum(bytes)/1024/1024/1024
  2  from cdb_data_files;


So there's some leeway. My APEX 20.1 install consumes around 350MB so even if it counts toward your total, I really don't think you'd want to be in a spot where 350MB is make or break for your app - that's running too close to the wire.

and you rated our response

  (1 rating)


July 24, 2020 - 11:52 am UTC

Reviewer: Alexander from outside of USA

Appreciate for answer.

My mistake was a hope to get formally correct answer from Oracle Corp. itself here )))
I guess, if fact, nobody cares about DB Express sizes, so even AskTom have just close to truth opinion.

I do beleive that Your answer is the closest to truth one.