Moving Audit Trails (AUD$ and FGA_LOG$) to a Different Tablespace

Hi all!
There is one thing that is always true for any version  of the Oracle Database: the audit trail simply keeps growing and growing.

Some important facts in this regard:
– It’s based on activity, not the amount of data changed.
– The default location of the database audit trail is the AUD$ table, in the SYSTEM tablespace.
– As you know, If this tablespace gets filled up there could be serious consequences.
– The same concern is true for FGA_LOG$, which is located in the SYSAUX tablespace.

Ok, so if you could move these two tables  to specific tablespaces, the root problem would be solved, right?

From 11g R2 on you can move the some or all audit trails to other tablespaces you choose. How?

To move the AUD$:

begin
dbms_audit_mgmt.set_audit_trail_location(
audit_trail_type => dbms_audit_mgmt.audit_trail_aud_std,
audit_trail_location_value => 'AUDIT_TBS');
end;
/

To move the FGA_LOG$:

begin
dbms_audit_mgmt.set_audit_trail_location(
audit_trail_type => dbms_audit_mgmt.audit_trail_fga_std,
audit_trail_location_value => 'AUDIT_TBS');
end;
/

 

There is only one important thing to keep in mind:  This tablespace needs to be online when the database is open. Otherwise, if any auditable operation try to be executed, you’ll get an ORA-02002.

This is something recommendable if you are setting the Auditing for your database. This is also something included Oracle in scripts like the Exacheck.

Hope it helps!
Cheers!

ORA-02158: invalid CREATE INDEX option while using redef_table on Oracle 12cR1

Hey all,
I’m working on a table redefinition project to migrate the existing tables and indexes to new compressed tablespaces. As the customer asked to have near 0 downtime to its data we decided to go with DBMS_REDEFINITION.

Simple right? Well… I sure hoped so.
I’m preparing a serie of posts about it, but before that I would like to share some hands on issues and that the magic of the new redef_table is not that great yet, at least on 12cR1/12.1.0.2.
Prior 12c, when would need to redefine a table you would use the DBMS_REDEFINITION and its 6 steps:

0 – Manually create a interim table to receive the data with the same structure as the original table
1 – DBMS_REDEFINITION.can_redef_table
2 – DBMS_REDEFINITION.start_redef_table
3 – DBMS_REDEFINITION.sync_interim_table
4 – DBMS_REDEFINITION.copy_table_dependents
5 – DBMS_REDEFINITION.finish_redef_table

And sometimes you would need to user the DBMS_REDEFINITION.REGISTER_DEPENDENT_OBJECT to help on some issues but if everything was good you would only need to do the steps above.

There are a few issues with the approach by that I mean BUGS 🙂 so you need to watch your back do an a good prep work.

In 12c you have a new procedure called DBMS_REDEFINITION.redef_table that would bundle all the 6 steps into one single procedure call. With its up and down side.
For me, the down side is that we can’t monitor the procedure, once this is no loger anything being recorded on dba_redefinition_errors.
By working as a transaction, everything works or its rolled back (Or it should but I will leave it for another post).

So the only way to know what is being done is to trace the session that is doing the redefinition. And that what I needed to do to see what was going on with a strange situation.

This is what was happening: I 1st tried the DBMS_REDEFINITION.redef_table and it raised ORA-02158: invalid CREATE INDEX option but when I used the 6 steps mentioned above (can_redef_table,start_redef_table,etc) it worked without issues:

That bugged me so I traced the session.

SQL> exec dbms_monitor.session_trace_enable(binds=>true,waits=>true);

SQL> BEGIN DBMS_REDEFINITION.REDEF_TABLE(uname => 'USER1',
tname => 'TEST1',
table_compression_type => 'COMPRESS FOR OLTP', 
table_part_tablespace => 'DATA_COMP', 
index_tablespace => 'DATA_COMP', 
index_key_compression_type   => 'COMPRESS ADVANCED LOW', 
lob_compression_type => 'COMPRESS HIGH', 
lob_tablespace => 'DATA_COMP', 
lob_store_as => 'SECUREFILE');
END;
/
BEGIN*
ERROR at line 1:ORA-02158: invalid CREATE INDEX option
ORA-06512: at "SYS.DBMS_REDEFINITION", line 3385
ORA-06512: at line 2

And this was the create index statement that was in the trace:

250438 PARSE ERROR #140737488293344:len=421 dep=1 uid=0 oct=9 lid=0 tim=3977494319094 err=2158250439 CREATE INDEX "USER1"."TMP$$_INDEX0" ON "USER1"."REDEF$_16752430_0" ("VISIT_NO")250440   PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS COMPRESS ADVANCED LOWNOLOGGING250441   STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645250442   PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1250443   BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)250444   TABLESPACE "DATA_COMP"

Can you see the issue?
Well neither could I, a colleague read the trace again and found a silly bug.

Here it is The create index had this:

COMPRESS ADVANCED LOWNOLOGGING

Instead of this, it had this:

COMPRESS ADVANCED LOW NOLOGGING

A silly space was missing and was causing the entire redefinition to fail!

I could not find any reference in MOS but that was it a space prevented to use the redef_table and caused me to lose some hours on it.

Hope this save you some time on your troubleshooting and I will be posting other strange situations that I found using the redef_table on Oracle 12cR1.

See you next post!

Elisson Almeida

Scheduler Job for OS Audit Trail Cleanup Routine

Hello all!
As you all know, most of OS files generated by oracle, like traces and logs can be cleared/managed using ADRCI. However, more than once, I saw filesystem get full of Audit Trail files.
In general, I see DBAs and companies implementing shell scripts to house keep those files. Usually some variation of the find with rm I posted some weeks ago. However, we have a very good “official” solition for this, using the DBMS_AUDIT_MGMT.

Basically we can create Scheduler Jobs in our databases to keep track on this. The advantages are seveal. The job clear in both nodes, this keep all Oracle information correctly updated, you may receive OEM notification for failure if monitoring jobs, etc.
You can see more detaiils here in MOS Note 731908.1 New Feature DBMS_AUDIT_MGMT to Manage and Purge Audit Information.

How I did?

1. Initial Cleanup to clear files older than a week.
2. Set last archive to a week ago.
3. Created Purge Job, purging older than a week

As per:

Continue reading

12c New Feature: Unused Privileges

Did you know 12c now has a mechanism to examine which privileges are actually being used by an user, module or for the database as a whole, as opposed to merely the privileges granted?
This is a great security improvement in order give users the privileges that they need precisely without granting too much.

Here’s how is works?

1. First you have to set up a capture process using the new package DBMS_PRIVILEGE_CAPTURE.

# Example:

BEGIN 
DBMS_PRIVILEGE_CAPTURE.CREATE_CAPTURE( 
        name         => 'all_priv_analysis_pol', 
        description  => 'database-wide policy to analyze all privileges', 
        type         => DBMS_PRIVILEGE_CAPTURE.G_DATABASE); 
END;
/

This starts the capture process database wide. Let it run for a bit.

2. Now you can either generate a report:

# Example

BEGIN 
DBMS_PRIVILEGE_CAPTURE.GENERATE_RESULT( 
        name         => 'all_priv_analysis_pol'); 
END;
/

Or examine the new views:

DBA_USED_PRIVS 
DBA_UNUSED_PRIVS 
DBA_USED_OBJPRIVS 
DBA_UNUSED_OBJPRIVS

3. To turn off you proceed with the following:

BEGIN 
DBMS_PRIVILEGE_CAPTURE.DROP_CAPTURE( 
        name         => 'all_priv_analysis_pol'); 
END;
/

So now you ensure that you use the best practice of least privilege for users.

Cheers!

Trace on Standby: Tracing MRP Process

Hey all!
Recently I got the following error when trying to start a trace in a standby. The idea was to start a trace in MRP to check on performance, but when trying to use DBMS_MONITOR.session_trace_enable:

oracle:standby-srvr /tmp: sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Fri Jan 19 14:07:56 2018

Copyright (c) 1982, 2014, Oracle. All rights reserved.

Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Advanced Analytics and Real Application Testing options

SQL> exec DBMS_MONITOR.session_trace_enable(session_id =>1970, serial_num=>55126, waits=>TRUE, binds=>TRUE);
BEGIN DBMS_MONITOR.session_trace_enable(session_id =>1970, serial_num=>55126, waits=>TRUE, binds=>TRUE); END;

*
ERROR at line 1:
ORA-06550: line 1, column 7:
PLS-00201: identifier 'DBMS_MONITOR.SESSION_TRACE_ENABLE' must be declared
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored

OMG!
Don’t panic, you can accomplish the same using oradebug:

-- In my case:
SQL> select process,pid from V$managed_standby where process like '%MRP%';

PROCESS PID
--------- ------------------------
MRP0 45693

SQL> oradebug setospid 19564
Oracle pid: 105, Unix process pid: 19564, image: oracle@standby-srvr (MRP0)
SQL> oradebug unlimit
Statement processed.
SQL> oradebug Event 10046 trace name context forever, level 12
Statement processed.
SQL>

You can apply same for any process/sid you need.

In case you desire to get the spid from a sid:

col machine format a30
col process format 999999
select p.spid,b.sid, p.pid
from v$session b, v$process p
where b.paddr=p.addr
and sid=&sid
/

Ok, and how to stop then?
Easy:

SQL> oradebug setospid 19564
SQL> oradebug Event 10046 trace name context off
SQL> oradebug tracefile_name

Enjoy!

Guru99: PL/SQL 101 Completely Free!

Hey all!
Just passing by today to share something I found really inetresting, and the best: it’s all free!
Do you know Guru99?

It’s a preety nice repository with lots of free tutorials and guides for PLSQL, SQL and several other languages, plus some other IT-related knowledge, like Big Data, PMP and etc.

It’s not rare to have people asking me “How to Start learning SQL” or saying “All material (including grepora :D) is too much specific, we don’t have good general documentation”.
Even Oracle having a pretty nice documentation on the products and features, general concepts are usually forgotten. Aaaaand, now I have something to link on those cases! 😀

Having a look on Guru99, First I found this guide PL/SQL First Program: Hello World, including detailed steps on:
– How to access SQL* Plus
– Connecting to Database
– How to write a simple program using PL/SQL
– Declaring and usage of variables in program
– Commenting Codes

Then found an entire category PL/SQL Tutorials. Talking to Alex (Editor), seems over 120 hours were spent on it. And they were well spent, the material is really very easy to read and understand. Chapters on this Course are:
1. Introduction to PL/SQL
2. Blocks in PL/SQL
3. PL SQL First Program: Hello World
4. PL/SQL Data Types
5. Complex Data Types in PL/SQL
6. PL/SQL Decision Making Statements
7. Loops in PL/SQL
8. Subprograms: Procedures and Functions in PL/SQL
9. Exception Handling in PL/SQL
10. SQL in PL/SQL
11. Packages in PL/SQL
12. Triggers in PL/SQL
13. Object Types in PL/SQL
14. Dynamic SQL in PL/SQL
15. Nested Blocks in Pl/Sql
16. PL/SQL Identifiers

Continue reading

Formatting DBMS_GET_DDL Output on SQLPlus

Hey all!
Issues when formatting output for DBMS_GET_DDL on SQLPlus? Me too!

Check below the best way to format it. Add to your scripts!

set long 20000 longchunksize 20000 pagesize 0 linesize 1000 feedback off verify off trimspool on
column ddl format a1000

begin
   dbms_metadata.set_transform_param (dbms_metadata.session_transform, 'SQLTERMINATOR', true);
   dbms_metadata.set_transform_param (dbms_metadata.session_transform, 'PRETTY', true);
end;
/
-- Now you command:
select dbms_get_ddl.xxx(..) as ddl from dual;

Hope you enjoy!
Cheers!