Prompted by comments made by readers about my posts describing how to add a second SCAN in 12c Release 1 and problems regarding the listener_networks parameter I thought it was time to revisit the situation. I’m still running Oracle Linux 7.1/UEK3 (although that should not matter) but upgraded to 18.104.22.168.5. This is the release that is reportedly showing the odd behaviour. I don’t recall my exact version when I wrote (more...)
I’ve updated my install cookbooks page to include a new cookbook for installation of Oracle 22.214.171.124 Real Application Clusters on Oracle Linux 6.7.
This is also the first one I’ve published since I left the employment of Violin Memory to work for Kaminario, so this install uses a Kaminario K2 All Flash Array. However, it applies very well to any Oracle RAC installation which uses relatively capable storage.
SystemTap and dynamic tracing tools in general give administrators great control on their systems with the relatively little additional effort to learn the new tools. In this post you will see of how SystemTap that can be used to modify data on the fly at runtime. The outcome is a form of "live patching". Examples are provided on how to apply these ideas to Oracle SQL parsing functionality. This type of "guru mode" use (more...)
The Oracle Service Bus has built in features to poll an IMAP of POP3 mail account. There are loads of excellent blog posts that exactly describe how to do it. However, when the mail server happens to be a Microsoft Exchange server, things become shady. Exchange’s IMAP implementation tends to be not really that compatible, and the server log will fill up with stacktraces such as:
javax.mail.MessagingException: Connect failed; nested exception is: java. (more...)
To do so in Linux you'll need to adapt the sudoers file.
Log in als root via het commando
[oracle@darlin-vce-db ~]$ su -
Last login: Fri Feb 26 06:44:05 EST 2016 on pts/0
Then edit the sudo-ers file:
[root@darlin-vce-db ~]# vi /etc/sudoersUncomment the lines for the (more...)
I was setting up disk devices for ASM in Oracle Linux 7. I knew things have changed between Oracle Linux 6 and Oracle Linux 7, but only just a little bit.
First of all, let’s take a look at the current disk usage. To see what disk devices are visible and how they are used, use lsblk:
# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT fd0 2:0 1 4K 0 disk sda 8:0 0 (more...)
The intention of this blogpost is to show the Oracle wait time granularity and the Oracle database time measurement granularity. One of the reasons for doing this, is the Oracle database switched from using the function gettimeofday() up to version 11.2 to clock_gettime() to measure time.
This switch is understandable, as gettimeofday() is a best guess of the kernel of the wall clock time, while clock_gettime(CLOCK_MONOTONIC,…) is an monotonic increasing timer, which means it (more...)
This is the second blogpost on using PL/SQL inside SQL. If you landed on this page and have not read the first part, click this link and read that first. I gotten some reactions on the first article, of which one was: how does this look like with ‘pragma udf’ in the function?
Pragma udf is a way to speed up using PL/SQL functions in (user defined function), starting from version 12. If you want (more...)
The recent progress and maturity of some of the Linux dynamic tracing tools has raised interest in applying these techniques to Oracle troubleshooting and performance investigations. See Brendan Gregg's web pages for summary and future developments on dynamic traces for Linux. Some recent work on applying these tools and techniques to Oracle can be found (more...)
Whenever you use PL/SQL in SQL statements, the Oracle engine needs to switch from doing SQL to doing PL/SQL, and switch back after it is done. Generally, this is called a “context switch”. This is an example of that:
-- A function that uses PL/SQL create or replace function add_one( value number ) return number is l_value number(10):= value; begin return l_value+1; end; / -- A SQL statement that uses the PL/SQL function select sum(add_one(id)) (more...)
There’s been a lot of work in the area of profiling. One of the things I have recently fallen in love with is Brendan Gregg’s flamegraphs. I work mainly on Linux, which means I use perf for generating stack traces. Luca Canali put a lot of effort in generating extended stack profiling methods, including kernel (only) stack traces and CPU state, reading the wait interface via direct SGA reading and kernel stack traces and getting (more...)
This post is about manually calling and freeing a shared latch. Credits should go to Andrey Nikolaev, who has this covered in his presentation which was presented at UKOUG Tech 15. I am very sorry to see I did miss it.
Essentially, if you follow my Oracle 12 and shared latches part 2 blogpost, which is about shared latches, I showed how to get a shared latch:
SQL> oradebug setmypid Statement processed. SQL> oradebug (more...)
I posted earlier in the year how to configure a Fedora instance to test PHP code on a local VM. However, I’ve got a few questions on how to find those posts. Here’s a consolidation with links on those steps:
In the first part of this series I said that RAM access is the slow component of a modern in-memory database engine and for performance you’d want to reduce RAM access as much as possible. Reduced memory traffic thanks to the new columnar data formats is the most important enabler for the awesome In-Memory processing (more...)
When you are migrating to Oracle 12c I hope you might this post useful. I came across this feature when researching what’s new with Oracle 12c (and yes I still find lots of new ones I haven’t noticed before). This one is a bit hidden away in section 126.96.36.199 Automatic Column Group Detection of the 12c New Features Guide. And it’s a lot more complex than I first thought! In this first post (more...)
SLES shell script to check required os packages according to documentation before starting oracle forms & reports installation
If you try to install oracle forms & reports 188.8.131.52 on SLES 11.3 than despite all installer checks are passed maybe you get a message like:
Error in invoking target ‘install’ of makefile ‘<FR_HOME>/sqlplus/lib/ins_sqlplus.mk’.
The reuirement check of the installer shows only missing openmotif classes which are not really required on SLES (see Doc ID 1567715.1), but no problems with a compiler or something similar.
Checking for binutils-2.19-11. (more...)
Post itself is divided into two parts:
- Oracle Linux installation (points 1 to 12)
- Vagrant box configuration (points 13 to 16)
Part 1 – Oracle Linux installation
1. Create a new Virtual Machine - machine name will be used later to create Vagrant (more...)