Using grant connect through to manage database links

Nobody can say that I am not current and topical with my posts. This post refers to functionality that was introduced in 9i, however I have just come across it and thought it useful enough to blog about it.

The command ALTER USER USERB GRANT CONNECT THROUGH USERA allows a proxy connection to be made using the username and password of USERA but  to connect in as USERB. The purpose is so that management of (more...)

Controlling RMAN channels on RAC

This was sent to me for posting  by my friend and ex-colleague Vitaly Kaminsky ….

I have recently worked with the customer where standard RMAN backups of production 2-node cluster (11.2.0.3) were getting too big and taking longer than 24 hours to run.

The problem with this particular cluster was the fact that ALLOCATION of RMAN connections to the instances of the cluster was controlled by SCAN and driven by the load-balancing (more...)

Loading timestamp with timezone into a table using SQL Developer

I will start this post off stating  that I know there are better and more efficient methods of doing this but this is the best method I could come up with.

I had a csv file with a number of columns, one of which was data in a timestamp with timezone format.

A few rows looked like this – note I have stripped the other columns out for ease of display.

DeviceId    Timestamp
7941    11/9/2014 (more...)

Progress update on my AWR repository

I received an email from a team member yesterday

Have you seen this? https://docs.oracle.com/database/121/TDPPT/tdppt_awr_warehouse.htm

Interesting idea – ever thought of implementing it?

Well of course I have implemented a AWR data repository and I thought I would catch-up on where I am with it and how it is being used.

The database started out on HPUX on 11.2.0.1 about 2 years ago and is now on Linux on 11. (more...)

How does statistic gathering fit in with ITIL Change Management processes

In the (good) old days there was only one optimizer and plans were developed based on the precedence of the rules. For some reason I have always thought there were 11 rules but looking at the manual it tells me there are 15 rules

Nowadays the vast majority of databases will be using the CBO and gathering statistics either by using the overnight maintenance functions or manually gathering as required. I suppose there is always (more...)

My misunderstandings regarding when indexes would not be used

It is normal for bloggers including myself to post about the great things they have done  – however in this case I am blogging about why I was surprised that adding a specific index had the substantial benefits it did have.

The table contains around 32M rows, is not partitioned and is on Linux 11.2.0.3


Name                                      Null?    Type
----------------------------------------- -------- ----------------------------
SELL_UNIT_ID                              NOT NULL VARCHAR2(20)
PRD_CD                                    NOT NULL VARCHAR2(75)
PRD_TYP_CD                                NOT  (more...)

Preventing standby databases opening in Active DataGuard mode + chopt !!!

It is long been a concern of mine that it is relatively easy to open a standby database  inadvertently and then be potentially liable to a licensing cost as usage is shown in the DBA_FEATURE_USAGE_STATISTICS view.

In fact we logged an SR on the subject based on experiences on failing over using DataGuard Broker

On dgmgrl switchover the Oracle restart database ‘start option’ property is not modified to ‘mount’ database even though dgmgrl modifies the (more...)

Valuable BAU OEM reports – some examples

A well configured OEM 12c (or any previous version of your choice) is a fantastic enterprise tool and the reporting capabilities are a major asset.

I am going to share three examples of reports we use and find valuable and if anybody has any  other good ideas I am happy  to hear about them.

I don’t think I wrote any of them but I almost certainly identified the requirement and instigated the creation of each (more...)

The value of audit_trail=DB,EXTENDED

I was recently reading a blog entry by Dominic Brooks regarding auditing and I was intrigued by the line referring to the audit_trail parameter being set to DB, EXTENDED

Behaves the same as AUDIT_TRAIL=DB, but also populates the SQL bind and SQL text CLOB-type columns of the SYS.AUD$ table, when available.

Nothing wrong with that and straight from the manual but I was surprised that they were CLOBS. However on looking at them they (more...)

Tidying up SYSAUX – removing old snapshots which you didn’t know existed

This post runs in parallel with a post I made 5 years ago and which is still the most read one on  this blog

http://jhdba.wordpress.com/2009/05/19/purging-statistics-from-the-sysaux-tablespace/

It will show how to reduce space taken up in the  SYSAUX tablespace by because you have many more AWR snapshots being retained than you think.

Firstly lets take an example database and we can see that we are using 92Gb  of space

 

set linesize 120
set  (more...)