Oracle Database 19.10.0, the January 2021 Release Update (RU), does seem to change some well known rules. Especially when you have a closer look to a backported feature, Blockchain Tables. But I will write a bit more about this change next week. For now, let’s have a closer look at New Parameters in Oracle 19.10.0 – and a default change.
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New Parameters in Oracle 19.10.0
This is the list of new parameters in the January 2021 Release Update 19.10.0:
|
Default
|
||
|---|---|---|
| blockchain_table_max_no_drop | maximum idle retention minutes for blockchain table | NONE |
| container_data | which containers should data be returned from? | ALL |
| max_auth_servers | Maximum size of auth pool | 25 |
| min_auth_servers | Minimum size of auth pool | 1 |
| optimizer_real_time_statistics | optimizer real time statistics on conventional DML | FALSE |
Interesting list for an RU. Just for comparison, between 19.8.0 and 19.9.0 you couldn’t find any new non-underscore parameter.
I added links to the parameter but at the time I’m writing this, only 2 of the 5 new parameters are documented in the 19c manuials. Once the missing parameters get added to the 19c documentation, I will add the links.
For now, you can rely on the 21c docs:
In addition, I found 17 new underscore parameters in Oracle 19.10.0. But most of them are related to bug fixes.
Real Time Statistics default change with Oracle 19.10.0
Daniel pointed me this week to our Optimizer Product Manager’s blog post, Nigel Bayliss wrote about a default change with Real Time Statistics.
The parameter optimizer_real_time_statistics is an Oracle 21c parameter which got backported to Oracle 19c for your convenience. Beforehand, you’d had to turn off Real Time Statistics with these underscore parameters:
- _optimizer_use_stats_on_conventional_dml = FALSE
- _optimizer_gather_stats_on_conventional_dml = FALSE
As Nigel wrote already, this is something only Exadata, ExaCC and ExaCS customers will need to be aware of. Real Time Statistics are not available on non-engineered systems and ODA. See the License Guide for further details:
ORA-12638 since Oracle 19.10.0 on Windows only
Please see this blog post describing the problem and the solution when you use Oracle 19.10.0 (or newer) Release Update on the MS Windows platform:
Further Links and Information
- Nigel Bayliss’ blog post about Real Time Statistics in 19.10.0
- optimizer_real_time_statistics in Oracle 21c
- Oracle Database 19c License Guide – Table 1-8: Performance
- ORA-12638 since Oracle 19.10.0 on Windows only
–Mike
DBA ORACLE
Mike,
Quick question. Are these new parameters documented in the RU documentation? Reason I am asking is that I am currently applying RU 19.9. The next round of patching will probably apply 19.11. So, if there are such changes, where can I find information about them? Of course, your blog is an excellent source of information, but you post right after the patch is relased whereas we apply patches months later, by which time, it slips my mind…
Thanks,
Arun
Hi Arun,
we figure out the best way to make sure everything is documented in the right place. This was a gap until now – but we are fixing this soon.
It hasn’t been finally decided whether it should be in the NEW FEATURES GUIDE with a new “RU/RUR” section or in the UPGRADE GUIDE where we track similar changes already.
Cheers,
Mike
Hi Mike,
i had a similar problem with 19.10. Bundle Patch on Windows now and would like to know where i can get the information before i get in trouble.
The Problem was “Windows Authentication No Longer Uses NTLM by Default”
It is a feature which is documented in Oracle 21c and also came with the 19.10 Bundle Patch. But in the Patch Notes and also Fixed Bugs Notes there is nothing to find about.
Because we are using OS Authentication with Backups and Monitoring Tools, we had a patch stop till the problem got solved, or better said, the feature was named.
The Support needed 3 weeks in the SR to find the problem and give me the information. That is really annoying.
In my opinion, this information has to be in the patch notes.
So much trouble because of that missing information 🙁
Hi Marcus,
I fully agree 🙁
Cheers,
Mike
Hi Mike,
interesting thing I discovered, I will open SR with Oracle.
based on Oracle documentation: https://docs.oracle.com/en/database/oracle/oracle-database/21/refrn/BLOCKCHAIN_TABLE_MAX_NO_DROP.html#GUID-26AF15B2-5621-4602-AA6E-D92842E4285C
from PDB level:
sqlplus / as sysdba
SQL> alter session set container=PDB1;
SQL> alter system set blockchain_table_max_no_drop=0;
alter system set blockchain_table_max_no_drop=0
*
ERROR at line 1:
ORA-01031: insufficient privileges
from CDB level:
sqlplus / as sysdba
SQL> alter system set blockchain_table_max_no_drop=0;
System altered.
Even though, its stated in the documentation that you can modify it from PDB level ?!
and the following parameter characteristics is identical to oracle documentation:
SQL> select
name,type,value,ISPDB_MODIFIABLE,ISINSTANCE_MODIFIABLE,ISMODIFIED,ISSYS_MODIFIABLE,DESCRIPTION
from
v$parameter
where
name=’blockchain_table_max_no_drop’;
Regards,
Emad
Hi Emad,
this may be a bug in terms of how the parameter is handled. You may please need to file an SR.
Based on all my testing I’d rather wait a bit when doing more than playing around with BC tables.
Cheers,
Mike
Hi Mike,
This is regarding the real time statistics parameter. I currently have the oracle database 19c Enterprise Edition installed on my on premises. Can I set the parameter “_exadata_feature_on” to true and try enabling the real time statistics? Will this serve as a workaround as the real time statistics feature has not been extended to non-engineered systems?
Hi Raj,
I can’t tell you whether this will work but trust me, at first you will reached mined license territory.
And second, you may rather want to have this feature not on. Hence, nothing to do for you on a non-Exa system
Only customers on Exa systems may need to turn it off at will.
Cheers
Mike