DST_UPGRADE_STATE set to DATAPUMP(1) when running preupgrade_fixups.sql

During the preparation for a 12.2 upgrade, I found that the preupgrade-tool reported about an incomplete DST upgrade, where DST_UPGRADE_STATE was set to "DATAPUMP(1)".

The preupgrade tool reported:

$ORACLE_HOME/jdk/bin/java -jar /tmp/preupgradetool/preupgrade.jar TERMINAL TEXT
Report generated by Oracle Database Pre-Upgrade Information Tool Version
12.2.0.1.0

Upgrade-To version: 12.2.0.1.0

=======================================
Status of the database prior to upgrade
=======================================


Complete any pending DST update operation before starting the database
     upgrade.

     There is an unfinished DST update operation in the database.  It's
     current state is: DATAPUMP(1)

     There must not be any Daylight Savings Time (DST) update operations
     pending in the database before starting the upgrade process.
     Refer to My Oracle Support Note 1509653.1 for more information.

Then, running the preupgrade_fixups.sql:

Fixup
Check Name                Status  Further DBA Action
----------                ------  ------------------
purge_recyclebin          Passed  None
pending_dst_session       Failed  Manual fixup required.
invalid_objects_exist     Failed  None
dictionary_stats          Passed  None

Result:

SYS@proddb01 SQL> r
  1  SELECT PROPERTY_NAME, SUBSTR(property_value, 1, 30) value
  2  FROM DATABASE_PROPERTIES
  3  WHERE PROPERTY_NAME LIKE 'DST_%'
  4* ORDER BY PROPERTY_NAME

PROPERTY_NAME                            VALUE
---------------------------------------- --------------------
DST_PRIMARY_TT_VERSION                   18
DST_SECONDARY_TT_VERSION                 14
DST_UPGRADE_STATE                        DATAPUMP(1)

According to https://blog.oracle-ninja.com/2013/09/17/stuck-timezone-upgrades-and-smart-scans the solution would be, as sysdba:

1. ALTER SESSION SET EVENTS '30090 TRACE NAME CONTEXT FOREVER, LEVEL 32';
2. exec dbms_dst.unload_secondary;

I tried this, with the following result:

SYSproddb01 SQL> SELECT PROPERTY_NAME, SUBSTR(property_value, 1, 30) value FROM DATABASE_PROPERTIES WHERE PROPERTY_NAME LIKE 'DST_%' ORDER BY PROPERTY_NAME;

PROPERTY_NAME                            VALUE
---------------------------------------- --------------------
DST_PRIMARY_TT_VERSION                   18
DST_SECONDARY_TT_VERSION                 0
DST_UPGRADE_STATE                        NONE

I also executed

ALTER SESSION SET EVENTS '30090 TRACE NAME CONTEXT FOREVER, OFF';

just to be on the safe side.

Finally, run preupgrade_fixups.sql again:

Check Name                Status  Further DBA Action
----------                ------  ------------------
purge_recyclebin          Passed  None
pending_dst_session       Passed  None
invalid_objects_exist     Failed  None
dictionary_stats          Passed  None

PL/SQL-prosedyren ble fullført.

And the test is passed, and you are ready to upgrade

Roles necessary to administer and view the Unified Audit Trail

Oracle 12c provides two new roles for auditing purposes:

AUDIT_ADMIN for audit configuration/administration
AUDIT_VIEWER for viewing and analyzing audit data

The following can role was granted by myself to allow a senior developer to view the audit information generated in a test database:

grant audit_viewer to scott;

https://docs.oracle.com/database/121/DBSEG/release_changes.htm#DBSEG000
https://docs.oracle.com/database/121/DBSEG/auditing.htm#DBSEG617

How to use dbms_application_info to create session details

The package dbms_application_info lets you add supplemental information in your session, which can be picked up in the V$SESSION view.

A very useful package, which I have used many times myself, but for some reason it is rarely used by Developers. It should typically be called before beginning a transaction in order to register and name a transaction/client_info/module for later use when measuring performance across an application.

exec dbms_application_info.set_client_info('Step one.');
exec dbms_application_info.set_module('module1','gettrades');

Here is an example where I was troubleshooting a "hanging" delete statement for a customer.
Turned out the problem was concurrency locks:

select SID,SERIAL#,SQL_ID,STATUS,osuser,machine,schemaname,MODULE,ACTION,CLIENT_INFO,LOGON_TIME,EVENT,STATE,FINAL_BLOCKING_SESSION "blocking"
from v$session 
WHERE schemaname='SALES'
AND STATUS='ACTIVE'
UNION
select SID,SERIAL#,SQL_ID,STATUS,osuser,machine,schemaname,MODULE,ACTION,CLIENT_INFO,LOGON_TIME,EVENT,STATE,FINAL_BLOCKING_SESSION "blocking"
from v$session 
where SID = (SELECT FINAL_BLOCKING_SESSION FROM V$SESSION WHERE schemaname='SALES' AND STATUS='ACTIVE');

In the resulting two rows, the first one is mine, the second is the blocking session:

SID	SERIAL#	SQL_ID	STATUS	OSUSER	MACHINE	SCHEMANAME	MODULE	ACTION	CLIENT_INFO	LOGON_TIME	EVENT	STATE	blocking
32	4759	5jg1839cyxzgh	ACTIVE	oracle	mytestserver.com	SALES	DELETE MODULE	DELETE_SCHEMA	Delete XSD.	15.02.2018 12:04:43	library cache lock	WAITING	2285
2285	48625	g3bc37vx8fy3u	INACTIVE	JIM	COMPANY\PC-157	SALES	SQL*Plus			14.02.2018 14:08:57	SQL*Net message from client	WAITING	NULL

For more information, check the documentation
Tracing Enhancements Using DBMS_MONITOR (In 10g, 11g and Above) (Doc ID 293661.1) at My Oracle Support.

How to view default settings for dbms_stats

Thanks to the author of the blog "Thinking out loud" for writing this piece of code. It makes it easy to view the default settings that applies when gathering schema statistics:

SELECT 
  username,
  DBMS_STATS.get_prefs(ownname=>USER,pname=>'INCREMENTAL') incr,
  DBMS_STATS.get_prefs(ownname=>USER,pname=>'GRANULARITY') grty,
  DBMS_STATS.get_prefs(ownname=>USER,pname=>'STALE_PERCENT') "stale%",
  DBMS_STATS.get_prefs(ownname=>USER,pname=>'ESTIMATE_PERCENT') "estimate%",
  DBMS_STATS.get_prefs(ownname=>USER,pname=>'CASCADE') cascade,
  DBMS_STATS.get_prefs(pname=>'METHOD_OPT') method_opt,
  DBMS_STATS.get_prefs(pname=>'DEGREE') degree,
  DBMS_STATS.get_prefs(pname=>'CONCURRENT') CONC
FROM dba_users
WHERE username IN ('BILL','BOB','SCOTT','JANE')
ORDER BY username;

USERNAME	INCR	GRTY	STALE%	ESTIMATE%	CASCADE	METHOD_OPT	DEGREE	CONC
BILL	TRUE	AUTO	10	DBMS_STATS.AUTO_SAMPLE_SIZE	DBMS_STATS.AUTO_CASCADE	FOR ALL COLUMNS SIZE AUTO	DBMS_STATS.DEFAULT_DEGREE	OFF
BOB	TRUE	AUTO	10	DBMS_STATS.AUTO_SAMPLE_SIZE	DBMS_STATS.AUTO_CASCADE	FOR ALL COLUMNS SIZE AUTO	DBMS_STATS.DEFAULT_DEGREE	OFF
SCOTT	TRUE	AUTO	10	DBMS_STATS.AUTO_SAMPLE_SIZE	DBMS_STATS.AUTO_CASCADE	FOR ALL COLUMNS SIZE AUTO	DBMS_STATS.DEFAULT_DEGREE	OFF
JANE	TRUE	AUTO	10	DBMS_STATS.AUTO_SAMPLE_SIZE	DBMS_STATS.AUTO_CASCADE	FOR ALL COLUMNS SIZE AUTO	DBMS_STATS.DEFAULT_DEGREE	OFF

Why doesn't dbms_stats.set_schema_prefs seem to work?

When trying to alter the default settings for statistics gathering on partitioned tables, I had troubles setting schema-level preferences using dbms_stats.set_schema_prefs:

exec dbms_stats.set_schema_prefs('SCOTT','INCREMENTAL','TRUE');

PL/SQL procedure successfully completed.

But when you check if the setting has been accepted using dbms_stats.get_prefs, it still seem to be set to FALSE:

SELECT  DBMS_STATS.get_prefs(ownname=>'SCOTT',pname=>'INCREMENTAL') "INCREMENTAL" FROM DUAL;

INCREMENTAL
--------------------
FALSE

I found the following note by Maria Colgan:

http://www.nocoug.org/download/2011-11/Maria_Colgan_Optimizer_Statistics.pdf

which states that set_schema_prefs only applies to current objects in the schema and that new objects will pick up global preferences instead.

So according to the note, I was doing the right thing, after all I was trying to alter the default behaviour for the optimizer when working on existing objects.

How come the new setting didn't seem to stick?

In my case, a global change was acceptable, so I could try to set the parameter globally instead, using set_global_prefs:

BEGIN
  dbms_stats.set_global_prefs('INCREMENTAL','TRUE');
END;
/

PL/SQL procedure successfully completed.

After that, the setting certainly seem to stick:

SELECT  DBMS_STATS.get_prefs(ownname=>'SCOTT',pname=>'INCREMENTAL') "INCREMENTAL" FROM DUAL;

INCREMENTAL
--------------------
TRUE

Maria points out that a global change like the one above will apply to all existing objects as well as any new objects.

My conlution is that dbms_stats.get_prefs will report the settings that applies for future objects only, not existing ones. If that is the case, the output of the report is ambiguous, as it will give the DBA the impression that he/she has not made the change permanent.

To view the default settings for a particular schema, see this post.

Oracle Documentation on the subject is here

How to display processes in Linux in a tree-like fashion

The simplest way to see operating system processes and their sub-processes is to use

ps aufx

Output will look something like the following, where I have used the Oracle agent and its child proceesses to illustrate the formatted process tree:

oracle   33037  0.0  0.0 162892 15600 ?        S    Jan29   0:06 /u01/oracle/product/agent13c/agent_13.2.0.0.0/perl/bin/perl /u01/oracle/product/agent13c/agent_13.2.0.
oracle   33127  0.3  0.9 2714968 313308 ?      Sl   Jan29   5:01  \_ /u01/oracle/product/agent13c/agent_13.2.0.0.0/oracle_common/jdk/bin/java -Xmx128M -XX:MaxPermSize=
oracle   48285  0.0  0.0 331652 23220 ?        S    15:41   0:00      \_ /u01/oracle/product/agent13c/agent_13.2.0.0.0/perl/bin/perl /u01/oracle/product/agent13c/agent

Alternatively, use pstree:

pstree -p
pstree -p 12345

where 12345 is the process id.

For example, the Oracle agent is started via a perl script, and spawns multiple java child processes:

 ps -ef |grep agent | grep perl
oracle    12345      1  0 08:53 ?        00:00:00 /sw/oracle/product/agent13c/GoldImage/agent_13.4.0.0.0/perl/bin/perl /sw/oracle/product/agent13c/GoldImage/agent_13.4.0.0.0/bin/emwd.pl agent /sw/oracle/product/agent13c/agent_inst/sysman/log/emagent.nohup

Use the process id as an argument to pstree to see all the child processes process 12345 has spawned (output abbreviated):

pstree -p 12345
perl(12345)───java(32690)─┬─{java}(32691)
                          ├─{java}(32692)

How to work around ORA-01017 in a migrated 12c database

You may see some users in your 12c database that have the password versions set to 10G:

select username, password_versions from dba_users where username='SCOTT';

USERNAME             PASSWORD_VERSIONS
-------------------- -----------------
SCOTT                10G

At the same time, most other users have their password_versions set to the value 10G 11G 12C.

Oracle uses different password versions in all these three versions:

* Oracle 11g it uses SHA1 password based version
* Oracle 10g uses DES based version.
* Oracle 12c uses SHA-2-based SHA-512 password version

Since the Oracle 12c database runs in exclusive mode by default, users with passwords generated in previous versions
will not be able to login (exclusive mode means that the SQLNET.ALLOWED_LOGON_VERSION_SERVER is set either to 12 or 12a).

Workaround is to force a password reset so that the password is generated for the current version.
But before you do that, you need to change the database's minimum allowed authentication protocol.
This is done by editing the file $TNS_ADMIN/sqlnet.ora.
The parameter controlling the sqlnet authentication protocol is SQLNET.ALLOWED_LOGON_VERSION_SERVER.

Here is how I did it:

1. Find the user(s) with password versions of 10G

select username, password_versions 
from dba_users 
where password_versions = '10G';

I have found cases where there is a space after the string '10G' so that you need to actually search for the string '10G '.

2. Edit the $TNS_ADMIN/sqlnet.ora file so that the database doesn't run in exclusive mode. Add

SQLNET.ALLOWED_LOGON_VERSION_SERVER = 11

3. Restart database

4. Expire the user(s) that you want to force a password reset for:

alter user SCOTT password expire;

5. Try to connect as the user:

connect SCOTT
Enter password:
ERROR:
ORA-28001: the password has expired


Changing password for SCOTT
New password:
Retype new password:
Password changed
Connected.

Check that the users now has the correct password version:

select username, password_versions,account_status from dba_users where username='SCOTT';

USERNAME             PASSWORD_VERSIONS ACCOUNT_STATUS
-------------------- ----------------- --------------------------------
SCOTT                10G 11G 12C       OPEN

6. When all the affected users have been changed, set the database to run in exclusive mode.
Change the SQLNET.ALLOWED_LOGON_VERSION_SERVER from 11 to 12 in $TNS_ADMIN/sqlnet.ora, and restart once more.