ORA-24247: network access denied by access control list (ACL)

SQL> begin
2 3 4
5 /
ERROR at line 1:
ORA-24247: network access denied by access control list (ACL)
ORA-06512: at “SYS.UTL_TCP”, line 19
ORA-06512: at “SYS.UTL_TCP”, line 280
ORA-06512: at “SYS.UTL_SMTP”, line 163
ORA-06512: at “SYS.UTL_SMTP”, line 199
ORA-06512: at “SCOTT.SEND_MAIL”, line 8
ORA-06512: at line 2

This error message means that no access control list has been assigned to the host you (more...)

Latches: What do we know ?

Latches are low level serialization mechanism which protects memory areas inside SGA. They are light wait and less sophesticated than enqueues and can be acquired and released very quickly.

Latch acquisition does not involve any complex algorithm and is based on test-and-set atomic instruction of a computer processor.

Latch Classification:

Latch can be classified in multiple ways:-

Shared latch and exclusive latch:

Shared latch is the one which can be shared by multiple processes/sessions.

Example (more...)

handling disks for ASM – when DB, Linux and Storage admins work together

A proper management of ASM Disks can be a complicated task.

On DOAG2015 I discussed with Martin Bach about the concept in my current company, where we implemented a setting which is consistent, robust and enables Storage, Linux and DB admins to work together easily.

As we started to think about ASM when 10.1 was out we tried to evaluate our possibility. asmlib was discarded quite early as it only increased complexity without additional (more...)

PL/SQL Formatting : More pearls of wisdom from Bryn

glasses-272399_1280-smallAnother topic of conversation that came out of Bryn‘s session at Oracle Midlands related to PL/SQL code formatting. I’m not sure I agree 100% with his opinion, but it’s certainly making me think about my current stance.

When I said I was going to blog about a couple of the points he raised, Bryn emailed me some stuff, which I’m going to use here. So this is Bryn’s content, with some of my opinions thrown in. I (more...)

Oracle Weblogic Maven Plugin Quickstart

If you have worked with maven in an enterprise environment probably you have followed recipes like this one (btw thanks Mykong!) in order to integrate Oracle libraries in your projects. But nowadays you can forget about all these tricks because since the beginning of the year the Oracle Maven repository is available for public access, hooray!!!

BGOUG 2015 Autumn Conference

The autumn BGOUG conference is now over. I planned to write a post immediately after the end of the conference when the enthusiasm and spirit is still fresh bee-zing but anyway it stays for quite a while  :)

This year it was the whole family attending the conference and my daughter Alex had an early Oracle start listening to Jonathan Lewis talking about execution plans.

This time we had about 370 people attending BGOUG. My presentation on (more...)

Tech 15

Monday 7th Dec: 11:20 – 12:05

I’ve arranged a panel session on the Cost Based Optimizer for UKOUG Tech 2015, with Maria Colgan, Nigel Bayliss, and Chris Antognini joining me to answer (and maybe argue about) questions from the audience.

To keep things moving along, we aim to have a few questions available before the day and collect a few questions at the door as well as accepting questions from the floor. Martin Widlake (more...)

Preventing PL/SQL name clashes. You learn something new every day!

glasses-272399_1280-smallI mentioned in yesterday’s Oracle Midlands post, Bryn had an example of some syntax I had not seen in 20+ years of PL/SQL development.

You tend to name PL/SQL parameters and variables in such a way as to prevent name clashes with table columns. Let’s cause an obvious name clash…

The table DUAL has a column called DUMMY with a single row with the value ‘X’.

SQL> select * from dual;


1 row  (more...)

Error count

This tiny Perl script might be used to report the error type and count for ASM disks in engineered systems, including Exadata. In those systems, the ASM uses griddisks, that are created from celldisks. The celldisks are in turn created from the physical disks.

errorCount.pl script

To quickly check for errors on any of those disks, we can use errorCount.pl Perl script. This is the complete script with comments:

# Process (more...)

How to rename ASM disk groups in Exadata

Deployment of Exadata requires you to generate configuration using Oracle Exadata Deployment Assistant (OEDA). Within the same the default  ASM disk groups names are DBFS_DG, RECOC1 and DATAC1. I usually change those to RECO01 and DATA01 as others doesn’t make sense to me and the only place where I find the default ones is on Exadata.

I had an incident last year where the Exadata deployed half way through and names were left by default (more...)

KISS video series for Analytic functions

Analytic functions still bamboozle many SQL practitioners out there.  So I’m building a suite of videos to walk people through some of the common questions we get asked that we need to solve with SQL, and look at how we can often solve them most simply using Analytic functions.

It will all be based on the KISS principle – Keep It Simply SQL, as it pertains to understanding the Analytic syntax.

You can (more...)

ORA-14758: Last partition … cannot be dropped

As a DBA, its awesome when you have the Partitioning option at your disposal.  So many cool things suddenly become either possible or easier.  For example, all of a sudden you can separate the data of different time ranges into different partitions. But hand in hand with that, was that fear that one day we’d be getting nasty stares from either managers or customers, when the following happened:

As a DBA, its awesome (more...)

Oracle Midlands : Event #12 – Summary

Tonight was Oracle Midlands Event #12 with Bryn Llewellyn  and Neil Chandler.

Bryn very kindly stepped in for Tom Freyer who unfortunately couldn’t make it. Bryn’s presentation was called Why use PL/SQL?, which was based on his whitepaper of the same name. I’ve written about a number of the topics he raised, including a piece on My Utopian Development Environment, but his talk and his whitepaper put forward a much more consistent and compelling argument. Definitely worth checking (more...)

Why Data Virtualization Is so Vital

In today’s day and age, it probably seems like every week you hear about a new form of software you absolutely have to have. However, as you’re about to find out, data virtualization is actually worth the hype.

The Old Ways of Doing Things

Traditionally, data management has been a cumbersome process, to say the least. Usually, it means data replication, data management or using intermediary connectors and servers to pull off point-to-point integration. Of (more...)

Why ALL Tools in at Your Disposal ARE IMPORTANT

After my AWR Warehouse session at DOAG in Nuremberg, Germany last week, an attendee asked me if he really needed to use trace files anymore with the value provided by AWR, (Automatic Workload Repository) and ASH, (Active Session History.)  I responded that trace files were incredibly valuable and should never be discounted.

To use an analogy, when I was 22 years old, and entered a doctor’s office missing a small percentage of my visual (more...)

Advanced Compression Option Caveat in Oracle 12c


Oracle 12c introduced a new capability to move a partition online, without any interruptions to DML happening at the same time. But, there’s a catch. So far we’ve been able to use basic table compression without having to worry about any extra licensing – it was just a plain EE feature.

If you are planning to use the online partition move functionality, carefully check if you’re not using basic compression anywhere. For example:

create (more...)

Promoting Unmanaged Targets Automatically

Recently a customer asked if it was possible to promote unmanaged targets automatically without any interaction. They were already using auto-discovery.

The answer is yes, and of course as soon as you see words like “without any interaction” you know there’s going to be scripting involved. In the Enterprise Manager world, scripting is handled by the EM Command Line Interface, better known as EMCLI. I’ve posted some example scripts of using EMCLI a while back (more...)

MobaXterm 8.4

While I was in India, a MobaXterm 8.4 was released.

Downloads and changelog in the usual places.

This is a must for Windows users who use SSH and X Emulation!



MobaXterm 8.4 was first posted on November 24, 2015 at 5:04 pm.
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AIOUG Sangam15 : It’s a Wrap!

The whole Sangam15 experience is over for me now!

Here are the posts I put out during the trip.

I did my thank you messages in the Day 2 post, but once again I would like to say a big thank you to AIOUG for inviting me, to the Oracle ACE Program for getting (more...)

AIOUG Sangam15 : The Journey Home

The night before a morning flight is always a little tricky for me. I lie in bed thinking, “What if I oversleep?”, which winds me up and makes it really hard to relax and drop off. I dozed on and off, but eventually gave up, turned the TV on and watched some films for a few hours.

I grabbed a quick breakfast and got the taxi to the airport. The hotel staff advised leaving (more...)