Oracle ACE Award

I have just learned that I have been nominated and accepted as an Oracle ACE. I would like to thank Jonathan Lewis for the nomination and Oracle Corp. for the recognition.


It’s a tremendous honour for me to receive this award. I just hope I can live up to it by continuing to serve the community, write some more blog posts (here) that people find useful, keep organising the UKOUG RAC, Cloud, Availability and Infrastructure (more...)

Goldengate Data Manipulation – When Inserts & Updates differ

One very useful aspect of Golden Gate is to allow the manipulation of data between the source and the destinations.

One recent problem that I encountered was to alter the data differently for inserts than for updates. This was caused by the receiving system needing to have some default data in columns which may or may not be supplied by the insert or update statements. This is slightly more complex than first imagined:

UKOUG Tech15 Call for Papers

The #ukoug_tech15 call for papers has gone out, and will be open until midnight on 10th May 2015


Last year was a fabulous event in Liverpool and we hope and expect it to be even better in Birmingham this year.

Full Disclosure: I am chairman of the UKOUG RAC, Cloud, Infrastructure and Availability SIG, and also on the Database stream judging and selection committee for Tech15. I am potentially open to bribes in the (more...)

Goldengate Log Rotation

Golden Gate 12 has some excellent commands to keep your log files in check, plus one glaring omission (scheduled for a future enhancement)

Each extract, datapump and replicat will be writing to report (.rpt) and discard (.dsc) files in the dirrpt directory (if you aren’t specifying a discard file, you should. They are very useful for troubleshooting)
If your system is up for a long time, these files are going to get large. (more...)


Just a small Sunday night anecdote with a wider point. I, or maybe a colleague, recently received an update statement from a developer. Now, this developer is long of tooth and is well versed in the ways of Oracle data manipulation.

The aforementioned update statement contained an interesting hint. BYPASS_UJVC. You may not have heard of this hint. It’s not commonly used, although it’s been around since Oracle 8.1.5. Mainly because it is (more...)

Auditing Read-Only Standbys

If your company has a passing interest in database security, you are probably running some sort of session auditing at the very least [audit session] (although this can also be useful for troubleshooting connectivity issues). There’s a reasonable chance you’re also running some level of object auditing, or even DML access auditing if your employer so dictates:

Check access/change of objects in the DB
  1  select audit_option, success, failure
  2  from dba_stmt_audit_opts
  3  union
  4   (more...)

Sequences – where did the view go?

I was pottering around with the sequence cache recently, investigating a few things like exactly when it refreshes (such as if it is flushed or aged from the shared pool – pin it!) and I was monitoring the next value using V$_SEQUENCE, like I have been since, erm, Oracle 8i in 1999 or summit.

I happened to log into an Oracle DB for a check-test and it was empty! My (more...)

Sequences – a quick guide and an unexpected quirk

Sequences on Oracle databases are simple, but there are some basic truths about sequences which need to be understood if you are going to use them, especially on RAC:


  1. Sequences will have “holes” in them, even if you specify NOCACHE (e.g. if you rollback your transaction).
  2. Don’t specify NOCACHE. It doesn’t scale.
  3. Sequences will NOT necessarily be, erm, sequential for your transactions. That will depend upon the COMMIT order and if you are (more...)

Goldengate: Problems with character sets

One complication that you may face with replicating data using Goldengate (or other tools) is when your source character set is different to your destination character set. This is particularly true when the source character set is UTF-8 and the destination is not.

If the application does not sanitise (or you do not want to sanitise) inputs to restrict them to the lowest common denominator within your systems, you will need to ensure that you (more...)

Checking the alert log – the easy way

Do you check the alert log of your databases every day? In the morning when you get in? But what about the alerts which happen during the day? How do you spot them – especially if you don’t have Grid Control or Cloud Control configured. Even if you do have a full monitoring solution, this can be useful for a belt-and-braces approach.

Here’s a short bash shell script to use adrci to read through each ORACLE_HOME (more...)