In praise of bloggers (along with sql_profiles and RAC interconnect pings)

Today I am going to mention two articles which I came across in the last few days whilst investigating problems and talk about the background to the problems but also praise the articles. I am sure many of us have run the SQL Tuning advisor from within OEM or using the DBMS_SQLTUNE package from the command line and often it recommends a sql_profile that should be applied, (invariably giving 99.98 perceived benefits). Now I (more...)

Don’t forget the emctl reload agent command

Just a quick entry to show the use of a command that I had forgotten existed but it seemed to work nicely

Problem  – OEM12C agent had been down for a few days on a non-production server and more than the maximum number of files had been created ready to be uploaded.

emctl status agent

Oracle Enterprise Manager Cloud Control 12c Release 2
Copyright (c) 1996, 2012 Oracle Corporation.  All rights reserved.
Agent  (more...)

aud$ and ASSM – a good combination

We had a 8 node RAC cluster that was showing evidence of connections timing out. The following AWR report segments indicates a high level of login activity and blocking on the AUD$ table and segments.




None of it conclusive but what was the kicker was the fact that the aud$ table was still in the system tablespace which is manually  managed and therefore automatic segment space management is not coming into play.

Over a 24 (more...)

The ‘rfs writes’ event on a DataGuard standby database

It is well known that poor performance on the standby server of a DataGuard pair can affect the performance of the primary database. This post shows an example and how to use the view GV$EVENT_HISTOGRAM to track down an issue.

The databases were on HPUX. I had been seeing alerts from OEM to state that the standby was seeing lag_apply delays when applying redo to standby. Looking at the primary database (more...)

Serious BUG alert – RMAN Duplicate overwrites datafiles at original location

Please be aware of the serious bug identified with RMAN duplicate database on the same node with versions and

Bug 13498382  ORA-1122 ORA-1208 RMAN Duplicate overwrites datafiles at original location despite db_create_file_dest

This note gives a brief overview of bug 13498382.
The content was last updated on: 07-FEB-2014
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Product (Component) Oracle Server (Rdbms)
Range of (more...)

Invisible Indexes – a real world example and a bit of LogMiner

We had a requirement to perform a one-off update on a table of around 1.2M rows. There were 11K statements similar to the one below, with varying values and predicates updating a variety of rows from 20 to 500. The potential elapsed time was around 44 hours due to the volume of full table scans involved.

The obvious thing to do was to create an index but this was production and it was urgent (more...)

Oracle Restart – going , going , gone?

Oracle restart is an 11GR2 feature which ensures that all services on a standalone installation start up in the correct order. As such it seems to work well. One bugbear I have with it is that it changes the order of entries in the /etc/oratab file. Personally I like my oratab to be ordered in terms of database (most used first), ASM, then agents. In that way when I logon to a box and it (more...)

2014 technology ambitions – just the two

As this the traditional time to layout resolutions for the year here are my 2 database related ones.

To understand more about some of the newer technologies and to advance my use of APEX as a means of providing reporting information around the systems and people I manage.

Having worked with the base Oracle RDBMS, and latterly SQL Server, for around 20 years I must admit that I am not as familiar with such terms (more...)

2013 blog activity

At the end of the year WordPress produce a brief analysis of activity on my blog

The Louvre Museum has 8.5 million visitors per year. This blog was viewed about 160,000 times in 2013. If it were an exhibit at the Louvre Museum, it would take about 7 days (more...)

Merry Xmas and a project goes live

I hope all my readers have a Merry Xmas and a Happy 2014.

My company has finally delivered an online delivery solution (we are a major food retailer in the UK  for anyone who does not recognise the branding). It is always nice to see a major project go-live and (more...)