Oracle Database 12c

New in Oracle 12c: _optimizer_gather_stats_on_load

Received an email from Roy last night with some performance issues a customer in the US encountered recently during their upgrade testing.

One issue the customer encountered has to do with tons of parallel slaves creating a massive noise on the system when they are doing a CTAS (Create Table As Select) – and the same thing happens with an IAS (Insert Append Select).

What caused this change?

In this case the behavior change is well documented, even though not linked to the responsible underscore parameter.

  • Oracle White Paper: Best Practices for Gathering Statistics –
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DBUA displays wrong RMAN backup for restore – Oracle 12.1.0.2

Related Blog Posts:


If you are using the Database Upgrade Assistant (DBUA) to upgrade your database to Oracle Database 12.1.0.2 be aware when you choose to potentially restore your database from a existing backup in case of an error during the upgrade.

First of all I would always stop DBUA …

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Don’t get puzzled by “sqlpatch” messages during Upgrade

During my last Hands-On-Labs in Uruguay and Argentina I’ve had several people wondering about these messages below when running the command line upgrade with catctl.pl:

catctl.pl - sqlpatch

This (and another) message breaks the nicely structured format of the catctl.pl output. And as it ends with an “err” extension it looks to many people as if the upgrade had gotten an error,

But please don’t feel disturbed. It’s just messages from sqlpatch invocation – and the “err” extension is just pointing to an error file in case something has gone wrong.

In a future release such messages …

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Oracle non-CDB architecture may be desupported after Oracle Database 12.2

You may wonder about the headline of this blog post.
Haven’t I blogged about this a long time ago?

Yes, I did. On January 22, 2015 – over 7 months ago:
https://mikedietrichde.com/2015/01/22/non-cdb-architecture-of-oracle-databases-is-deprecated-since-oracle-database-12-1-0-2/

But whenever in the past weeks this message has been refreshed and got a bit more precise (which I’d guess everybody appreciates). Now we are clearly saying that such a change won’t happen with Oracle 12.2. Before we’ve said only “in a later release“.

See the Oracle Database 12c Upgrade Guide:

Deprecation Note non-CDB architecture

In case you’d like to explore the world of (at least) Oracle Single Tenant …

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DBMS_STATS. GATHER_DICTIONARY_STATS fails with ORA-20001 ORA-6502 ORA-6512 – Concurrent Stats

I really have to say “Thank you very much” to the people out there alerting me about issues I haven’t seen before. Just in the past week I’ve got to learn about three issues which are related to the upgrade – and I haven’t seen before. Please don’t expect me always to follow up with the progress of your SRs or the related bugs. But your experiences are such an important source for me – so thanks again!

The most recent issue (thanks to Bernd Tuba from MM Warburg) …

Symptom

execute dbms_stats.gather_dictionary_stats

ORA-06502: PL/SQL: numeric or value 
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Invalid Table Data before Upgrade to 12.1.0.2?

You plan to upgrade your database(s) to Oracle Database 12.1.0.2,?

You did run the preupgrd.sql including the preupgrade package in your current database already?

But in the preupgrade.log you’ll see the following ERROR:

ERROR: --> Invalid Oracle supplied table data found in your database.

     Invalid data can be seen prior to the database upgrade
     or during PDB plug in.  This table data must be made
     valid BEFORE upgrade or plug in.

   - To fix the data, load the Preupgrade package and execute
     the fixup routine.
     For plug in, execute the fix up routine in the PDB.

    @?/rdbms/admin/utluppkg.sql
SET SERVEROUTPUT 
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DBCA 12c and “datapatch.pl” – things to know

A few weeks ago I did blog about the DBUA (Database Upgrade Assistant) not executing ‘datapatch’ (i.e. not applying the SQL changes involved with a SPU/PSU/BP) automatically:

For DBUA, please note that this behavior DOES NOT APPLY to command line upgrades done with catctl.pl – as you can see from this somewhat disturbing messages during the upgrade in phase 65 and phase 69 (which are not errors but just informational messages for datapatch’s execution):

Datapatch phases command line upgrade catctl.pl

But afterwards I have learned that things are worse.
The same behavior is true when you create

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Oracle Databases and Microsoft Windows 10

Please find a more current blog post about certification of Oracle Database 12c on MS Win 10 here:

MS Windows 10


If you have upgraded already or plan to upgrade to Microsoft Windows 10 in the near (or later) future, you may find this Statement Of Direction by Oracle regarding Microsoft Windows 10 certification quite useful:

http://www.oracle.com/technetwork/database/windows/whatsnew/oracle-db-win10-sod-2626195.pdf

In summary:

  • Oracle plans to certify Oracle Database 12.1.0.2 by October 2015
  • Oracle plans to certify the next major version of the database as well on MS Win 10 – 64bit

Addition [Oct, 22, 2015]:

  • Oracle VirtualBox 5.0.8 released
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Other people’s thoughts: “Should you upgrade to 12c?”

You still don’t believe me yet when I say: You can’t seriously wait for the so called 2nd release of Oracle Database 12c as it will be an entirely new release again? And you haven’t upgraded yet to Oracle Database 12.1.0.2 for various reasons?

Then sometimes it’s good to listen to other people’s opinions – and I’m happy to share this 6 minute video by Tim Hall (very well known for his great page oracle-base). Listen to Tim and his Thoughts about Upgrading to Oracle Database 12c. And don’t get disturbed that he’s driving on the wrong …

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Optimizer Issue in Oracle 12.0.1.2: “Reduce Group By”

Wrong Query Results BugDBAs biggest fears I’d guess are Optimizer Wrong Query Results bugs as usually the optimizer does not write a message into the alert.log saying “Sorry, I was in a bad mood today …”.

The Oracle Database Optimizer is a complex piece – and in Oracle 12c it delivers great performance results. Plus (my personal experience when you know what to do) it is more predictable which I like a lot when changing databases from one to another release. But due to its complexity sometimes we see issues – and sometimes it is necessary to switch off tiny little pieces …

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SAP on Oracle Database 12c now with Oracle In-Memory

Oracle SAPOn March 31, 2015 SAP has been certified to run on Oracle Database 12.1.0.2:

As of June 30, 2015, Oracle Database In-Memory is supported and certified for SAP environments for all SAP products based on SAP NetWeaver 7.x. on Unix/Linux, Windows and Oracle Engineered Systems platforms running Oracle Database 12c – in single instance and Oracle Oracle Real Application Clusters deployments.

Oracle Database 12c is the database of choice for SAP customers based on In-Memory Technology which is fully supported for SAP BW and SAP OLTP applications.

For …

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Log Writer Slave Issues in 12.1.0.2 – mainly on IBM AIX and HP-UX but also on Linux

Currently we see a lot of issues with the Multiple Logwriter feature in Oracle Database 12.1.0.2, especially on the IBM AIX platform.

What are Multiple LGWRs?

You will see multiple LGnn (Log Writer Worker) processes on multiprocessor systems, The LGWR (Log Writer) creates worker processes (slaves) to improve the performance of writing to the redo log. LGnn (Log Writer Worker) processes are not used when there is a SYNC standby destination. Possible processes include LG00LG99.

Here is a list of new background processes in Oracle Database 12.1:
MOS Note 1625912.1 – New Background

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Package Differences between Oracle 11.2.0.4 and 12.1.0.2?

The question sounds pretty trivial:

Which packages did exist in Oracle 11.2.0.4 but don’t exist in Oracle 12.1.0.2 anymore?

And going a bit deeper into the topic,

Which procedures and functions calls of SYS packages have been changed since then?

A colleague of mine (thanks to Thomas Kempkens from ACS Support for writing up a fancy procedure – all credits go to him) had to dig this out for a customer,

See the result.
These packages don’t exist in Oracle 12.1.0.2 anymore but did exist in Oracle 11.2.0.4 (without PSUs):

CWM2_OLAP_INSTALLER
DBMS_AMD
DBMS_APPCTX
DBMS_DBLINK
DBMS_DM_IMP_INTERNAL
DBMS_DM_UTIL_INTERNAL
DBMS_DUMA_INTERNAL
DBMS_JDM_INTERNAL
DBMS_RULE_COMPATIBLE_90
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Oracle 12.1.0.2 – Security Behavior Change with non-SYSDBA Triggers

Oracle Database SecuritySometimes things get revealed at unexpected occasions. This one happened during a recent customer upgrade to Oracle Database 12c with a 3rd party geospatioanl application installed (ESRI).

At the very end of the upgrade the customer saw many ORA-1031 (insufficient privileges) errors and it seemed to be that nothing was working correctly anymore.

This happened during the run of catupend.sql. The following code path in  catupend.sql causes the error.

cursor ddl_triggers
is
select o.object_id from dba_triggers t, dba_objects o
where t.owner = o.owner and t.trigger_name = o.object_name and o.object_type = 'TRIGGER'
and (t.triggering_event like '%ALTER%' or t.triggering_event like '%DDL%');
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SAP is now certified on Oracle Database 12.1.0.2

ORACLE and SAPSAP certified Oracle Database 12.1.0.2 as of March 31, 2015!

Yes, it’s true. Our colleagues in the Oracle/SAP/CompetenceCenter in Walldorf worked really hard to complete the certification for SAP with Oracle Database 12.1.0.2 But finally it happened. Actually it was announced long time before as planned. And it happened right in time.

Please find the official documents here:

SAP Service Marketplace ==> Products ==> Installation & Upgrade Guides ==> Database Upgrades (login required) ==> Oracle 

And here’s the link to the official

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New Behaviour in Oracle Database 12c and 11.2.0.4: SELECT ANY DICTIONARY with reduced privilege set

You’ve just upgraded to Oracle Database 12c – but your favorite admin tool receives an ORA-1031: Insufficient Privileges after connection?

Then the reason may be the reduced set of privileges for the SELECT ANY DICTIONARY privilege. This privilege does not allow access to tables USER$, ENC$ and DEFAULT_PWD$, LINK$, USER_HISTORY$, CDB_LOCAL_ADMINAUTH$, and XS$VERIFIERS. Actually such changes are not new. For instance in Oracle 10.1 we removed the access to  LINK$ in SELECT ANY DICTIONARY (well, this may have happened because the dblink’s password was stored in clear text in LINK$ – a misbehavior which is fixed since

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Why you seriously can’t wait for the second release!

Premier Support for Oracle Database 11.2 has ended 4 weeks ago at 31-January-2015. 

I think most Oracle DBAs are aware of it. And I have stressed the topic about the need to upgrade to Oracle Database 12.1.0.2 a lot in the past months via the blog, in workshops and in discussions and customer meetings.

But there are still plenty of people out there you would like to wait for Oracle Database 12.2, the so called “secondrelease. From looking backwards I can understand this thinking. Neither Oracle 9.0 nor Oracle 10.1 were the best and most …

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Downgrade Oracle Restart 12c – Grid Infrastructure only?

Oracle RestartCan you downgrade your Oracle Restart installation from Oracle 12c back to Oracle 11g?

Actually there’s no real direct downgrade supported for Oracle Restart. But of course there’s a way to do it.

Basically it is:

  • Deconfigure Oracle Restart in 12c
  • Configure Oracle Restart in 11g

But wait a minute. It is very important to know if you have upgraded your database already. If that is the case then first you MUST downgrade your database(s) as you can’t manage a higher version Oracle Database with a lower version Clusterware.

So first of all, please downgrade your Oracle database(s) first:…

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Is it always the Optimizer? Should you disable Group By Elimination in 12c?

I wouldn’t say it’s always the optimizer – but sometimes one or two tiny little things are broken making it necessary to turn off new functionality for a while.

Please don’t misinterpret this posting!
As far as I see (and I really do work with customers!) I’d state the Oracle Database 12.1.0.2 Optimizer is more stable, faster and predictable compared to 11.2.0.x. Our Optimizer Architects and Developers have done a great job. But with all the complexity involved sometimes it takes a few fixes or incarnations until a great new feature really matures. The Group-By-Elimination feature in Oracle Database …

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Hands-On-Lab “Upgrade, Migrate & Consolidate to Oracle Database 12c” available for DOWNLOAD now!

Wow … that was a hard piece of work. Roy put a lot of effort into getting our Hands-On-Lab on OTN for download. We promised to have it available after OOW – or at least a description how to create it by yourself. And finally it’s there. Find it here:

A few important things to mention before you start the download:

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Upgrade to 12c and Plugin – one fast way to move into the world of Oracle Multitenant

What is the best way to move into Oracle Multitenant (which includes Single Tenant with just one PDB) as well?

This question came up on the blog, it’s part of the Multitenant chapter in our big slide deck but let me elaborate this a bit more in detail. Of course there are several ways to move a database into a Single/Multitenant environment such as Data Pump but one fact is for sure: You can’t convert a stand-alone database to become a container database (CDB$ROOT). A container database has to be built up from scratch as first step. Please …

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Non-CDB architecture of Oracle databases is DEPRECATED since Oracle Database 12.1.0.2

Please find an updated blog post here:

as the text in the Database Upgrade Guide has been changed as well.


non-CDB deprecated in Oracle 12.1.0.2

What does this mean?

Deprecation first of all does not mean “desupported”. It means in this case that you of course can have still stand-alone Oracle databases as you know the architecture from previous releases. But you can also have a single-tenant deployment (a CDB with one PDB – no Multitenant license required) or multitenant databases (a CDB with up to 252 PDBs – Multitenant Option license required).…

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New MOS Notes on Database Upgrades for 12c with or without Oracle Multitenant

Please find some new MyOracle Support (MOS) Notes about Database Upgrades to Oracle Database 12c, with or without Oracle Multitenant:

Credits for the CDB/PDB Notes go to

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