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.
New Parameters in Oracle 19.10.0
This is the list of new parameters in the January 2021 Release Update 19.10.0:
|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:
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