Creating or modifying an Oracle Database user password can be done by using any standard password generator you can find on the WEB. But I wanted a password to comply to “ora12c_strong_verify_function”, and this isn’t as easy to generate as you might expect. Though most generators provide options to include or exclude certain character groups, I wasn’t able to find one that will let you choose options in any detail and also let you set (more...)
It’s been a busy month – five Exadata deployments in the past three weeks and new personal best – 2x Exadata X6-2 Eighth Racks with CoD and storage upgrade deployed in only 6hrs!
An issue I encountered with the first deployment was that onecommand wouldn’t change the storage cells names. The default cell names (not hostnames!) are based on where they are mounted within the rack and they are assigned by the elastic configuration (more...)
Es geht los bis zum 13.2.2017 können Vorträge für den Exaday 2017 rund um das Thema Oracle Engineered Systems eingereicht werden
Ich freue mich auf viele spannende Vorträge …
Der Exaday 2017 findet dieses Jahr am 20. Juni 2017 in Frankfurt – Mörfelden statt
The Call for Paper is opened until 13.2.2017
Please submit for the Exaday 2017 all around the topic Oracle Engineered Systems
I had the pleasure to deploy another Exadata in the first week of 2017 and got my first issue this year.
As we know starting with Exadata X5, Oracle introduced the concept of Elastic Configuration. Apart from allowing you to mix and match the number of compute nodes and storage cells they have also changed how the IP addresses are assigned on the admin (eth0) interface. Prior X5, Exadata had default IP addresses set at (more...)
When I carried out my first Exadata patching, I came across ‘Linux Screen‘ in the documentation, which Oracle recommended to use when patching:
“It’s recommended to run the dbnodeupdate.sh session using the Linux ‘screen’ or ‘vnc’ utility such that when a network problem breaks the connection to the server the patching session continues.”
Basically ‘Linux Screen‘ allows you to:
- Have a shell that can be reconnected to if you (more...)
The upcoming SLOB 2.4 release will bring improved data loading error handling. While still using SLOB 2.3, users can suffer data loading failures that may appear–on the surface–to be difficult to diagnose.
Before I continue, I should point out that the most common data loading failure with SLOB in pre-2.4 releases is the concurrent data loading phase suffering lack of sort space in TEMP. To that end, here is an example of (more...)
There is a very interesting paper about the way of direction of the Exadata Database Machine.
Thanks a lot Günther Stürner.
While writing the previous two posts about GTTs and Smart Scan, I stumbled across an interesting observation. When I started putting my thoughts to (virtual) paper, I thought it was going to be a short post. Well, it wasn’t to be, again. Anyway, you might find this interesting.
If you read the previous posts this code example I used to populate the GTT might look familiar:
insert /*+ append */ into gtt select (more...)
Recently I did a upgrade to Grid Infrastructure 220.127.116.11 on a few Exadata Clusters
Here my summary of the installation
Before you start please read the following MOS note 1681467.1. This note is very helpful and describes the whole procedure in a Exadata environment
It’s not only the Upgrade to 18.104.22.168. In the same „session“ I also install the GI PSU Jul 2016 and the Oneoff Patch (more...)
Continuing the example of the previous blog post (is it possible to Smart Scan GTTs?), I am investigating if Smart Scans against GTTs can benefit from Flash Cache, or “optimised reads”. The easiest way to see this in your session is to calculate the change in session counters based on v$mystat or v$sesstat. Other tools might also provide information about the amount of data read from Flash Cache, but there are quite often extra (more...)
A question that has come up while preparing to deliver another Exadata Optimisation Class is whether you can offload queries against Global Temporary Tables (GTT) or not. There are subtle differences between heap tables and GTTs such as how statistics are handled and where they are stored that merit a little investigation.
I have used the lab environment on the X3-2 (Exadata 22.214.171.124.0, 126.96.36.199.160419 RDBMS) to test (more...)
One of the things you can do with Pin, is profile memory access. Profiling memory access using the pin tool ‘pinatrace’ is done in the following way:
$ cd ~/pin/pin-3.0-76991-gcc-linux $ ./pin -pid 12284 -t source/tools/SimpleExamples/obj-intel64/pinatrace.so
The pid is (more...)
This blogpost is an introduction to Intel’s Pin dynamic instrumentation framework. Pin and the pintools were brought to my attention by Mahmoud Hatem in his blogpost Tracing Memory access of an oracle process: Intel PinTools. The Pin framework provides an API that abstracts instruction-set specifics (on the CPU layer). Because this is a dynamic binary instrumentation tool, it requires no recompiling of source code. This means we can use it with programs like the Oracle (more...)
This blogpost is about the Oracle redo log structures and redo efficiency in modern Oracle databases. Actually, a lot of subtle things changed surrounding redo (starting from Oracle 10 actually) which have gone fairly unnoticed. One thing the changes have gone unnoticed for is the Oracle documentation, the description of redo in it is an accurate description for Oracle 9, not how it is working in Oracle 10 or today in Oracle 12.1.0. (more...)
If you manage an Oracle Engineered System you may wonder how well your Smart Scans are performing. Are you taking full advantage of Exadata Optimizations? If so, how do you measure them?
Sample chart below is from a data warehouse DW application. It (more...)
Noch eine Woche und ein paar Tage dann startet die DOAG Konferenz 2016.
Es warten viele Interessante Themen rund um das Thema Oracle.
Einfach mal über den Link ins Vortragsprogramm schauen.
Read this post if your Exadata compute nodes have 512/768GB of RAM or you plan to upgrade to the same.
There has been a lot of information about hugepages and I wouldn’t go into too much details. For efficiency, the (x86) CPU allocates RAM by chunks (pages) of 4K bytes and those pages can be swapped to disk. For example, if your SGA allocates 32GB this will take 8388608 pages and given that Page Table (more...)
Recently I was asked to analyse the security impact of the snmp daemon on a recent Exadata. This system was running Exadata image version 188.8.131.52.3. This blog article gives you an overview of a lot of the things that surround snmp and security.
First of all what packages are installed doing something with snmp? A list can be obtained the following way:
# rpm -qa | grep snmp net-snmp-utils-5.5-54.0. (more...)
In the wake of the great hospitality shown by the OTN crew at Open World, Tim Hall thought that getting the community together for a series of “OTN appreciation” blogs would be a good way to show our thanks back.
Thinking about tools provided by Oracle that make my life easier, my mind went to dbnodeupdate.sh. This tool helps automate many of the tedious tasks that must be performed when performing an OS update on an Exadata compute (more...)
Yes, this is well-known and the process has been described in Exadata Write-Back Flash Cache – FAQ (Doc ID 1500257.1) but what the note fails to make clear is that you do NOT have to restart cell services anymore hence resync the griddisks!
I had to enable the WBFC many times before and every time I’d restart the cell services, as note suggests. Well, this is not required anymore, starting with 11.2.3. (more...)