opatch investigations

This blogpost is about opatch and how to obtain information about the current oracle home(s), and how to obtain information about the patches to be applied.

Patches that can be applied using opatch are provided by oracle as zip files which have the following naming convention:
p[patchnumber]_[baseversion]_[platform]-[architecture].zip. The patch normally contains an XML file called ‘PatchSearch.xml’ and a directory with the patch number. Inside the patch number directory there is a README.txt (more...)

opatch versions

This blogpost is about oracle’s patching tool for the database and grid infrastructure: opatch. I personally have a love/hate relationship with opatch. In essence, opatch automates a lot of things that would be very error prone if it were to be done by hand, which is a good thing. However, there are a lot of things surrounding opatch that I despise. An example of that is the version numbering of opatch itself.

Versions and more (more...)

Arbeitsgruppen Treffen „Engineered Systems“ in Nürnberg

Wie jedes Jahr trifft sich die Arbeitsgruppe „Engineered Systems“

am Vorabend der Konferenz.

Termin: Montag, den 19.11.2018, um 17:00 Uhr

Ort: Nürnberg, ConventionCenter Ost Messezentrum, 90471 Nürnberg

Der Raum befindet sich im Zwischengeschoss

Wir haben spannende Themen auf der Tagesordnung und das Oracle Exadata und ODA Product-Management ist ebenfalls vor Ort.

Es wird wie immer interessant mit vielen Neuigkeiten rund um die Engineered Systems

Das Networking kommt natürlich auch nicht zu kurz

Wir sehen (more...)

FIRST_ROWS_10 CBO Is Hopeless, It’s Using The Wrong Index !! (Weeping Wall)

There’s an organisation I had been dealing with on and off  obeer the years who were having all sorts of issues with their Siebel System and who were totally convinced their performance issues were due directly to being forced to use the FIRST_ROWS_10 optimizer. I’ve attempted on a number of occasions to explain that their […]

Oracle wait event ‘TCP Socket (KGAS)’

I was asked some time ago what the Oracle database event ‘TCP socket (KGAS)’ means. This blogpost is a deep dive into what this event times in Oracle database 12.1.0.2.180717.

This event is not normally seen, only when TCP connections are initiated from the database using packages like UTL_TCP, UTL_SMTP and the one used in this article, UTL_HTTP.

A very basic explanation is this event times the time that a database (more...)

ODC Appreciation Day : Oracle dcli Utility

What is ODC Appreciation Day?

The Oracle Developer Community (ODC) Appreciation Day formally known as OTN Appreciation Day, is a great initiative by Tim Hall aka Oracle-Base.com.  Where we take the opportunity to say thanks to the Oracle Developer Community #ThanksODC.

More info on Oracle Developer Community can be found here:
About Oracle Developer Community

When is it?

This year, it is on Thursday 11th October 2018.

You can see my previous (more...)

Few Exadata MOS Docs to review

If you have MOS login credentials and managing Exadata database machines, below is the list of few MOS Doc which is worth reading:

  • 888828.1, "Exadata Database Machine and Exadata Storage Server Supported Versions"
  • 1070954.1, "Oracle Exadata Database Machine Exachk or HealthCheck"
  • 1353073.2, "Exadata Diagnostic Collection Guide"
  • 1500257.1, " Exadata Write-Back Flash Cache - FAQ"
  • 1553103.1, "dbnodeupdate.sh and dbserver.patch.zip: Updating Exadata Database Server Software using the DBNodeUpdate Utility (more...)

Resolving Slow Performance, Skipped Checks and Timeouts on Exa Check (exachk)

Background

For more information with regards to Exa Check, please read the following post:
How to use Oracle Exadata Database Machine Exa Check (exachk)

Slow Performance, Skipped Checks and Timeouts

When running the latest exachk (at time of writing, version 18.3.0_20180808), you may notice it takes a long time to run compared to the past.  This is due to the vast amount of additional checks carried out by the tool.  Due to (more...)

using AWR on Exadata

Oracle released a brand new Whitepaper for Exadata

How to use AWR Report on Exadata Machines

This Whitepaper gives details how the AWR reports can be used in conjunction with Exadata to monitor and analyze database performance issues

http://www.oracle.com/technetwork/database/availability/exadata-maa-best-practices-155385.html

 

 

 

Extending the root LVM Partition on Exadata

On an Oracle Exadata Database Machine, the ‘/’ (root) is defaulted to a size of 30Gb, which can easily fill up.  Luckily this is just a Logical Volume and there’s normally lots of space available on the Logical Volume Group which is usually untapped.

Extending ‘/’

Identify how much space is used and free on ‘/’ using df:

[root@v1ex1dbadm01 ~]# df -h /
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VGExaDb-LVDbSys1
                       30G   22G   (more...)

All about headroom and mandatory patching before June 2019

This post was triggered upon rereading a blogpost by Mike Dietrich called databases need patched minimum april 2019. Mike’s blogpost makes it clear this is about databases that are connected using database links, and that:
– Newer databases do not need additional patching for this issue (11.2.0.4, 12.1.0.2, 12.2 and newer).
– Recent PSU patches contain a fix for certain older versions (11.1.0.7, 11.2. (more...)

Oracle database wait event ‘db file async I/O submit’ timing bug

This blogpost is a look into a bug in the wait interface that has been reported by me to Oracle a few times. I verified all versions from Oracle 11.2 version up to 18.2.0.0.180417 on Linux x86_64, in all these versions this bug is present. The bug is that the wait event ‘db file async I/O submit’ does not time anything when using ASM, only when using a filesystem, where (more...)

A re-introduction to the vagrant-builder suite for database installation

In a blogpost introducing the vagrant builder suite I explained what the suite could do, and the principal use, to automate the installation of the Oracle database software and the creation of a database on a virtual machine using vagrant together with ansible and virtual box.

This blogpost shows how to use that suite for automating the installation of the Oracle database software and the creation of a database on a linux server directly, with (more...)

exachk 18.2.0_20180518 released

Oracle released the new Version of exachk. The version is shown as 18.2.0_2018052018 so far so good. The next sentence in the Note is: „What’s new in exachk 12.2.0.1.4 may be found in the „What’s New in 12.2.0.1.4″ section of the User’s Guide available here..“

The new Release model from Oracle is really confusing. From my point of view it makes no sense that you download (more...)

A look into oracle redo, part 11: log writer worker processes

Starting from Oracle 12, in a default configured database, there are more log writer processes than the well known ‘LGWR’ process itself, which are the ‘LGnn’ processes:

$ ps -ef | grep test | grep lg
oracle   18048     1  0 12:50 ?        00:00:13 ora_lgwr_test
oracle   18052     1  0 12:50 ?        00:00:06 ora_lg00_test
oracle   18056     1  0 12:50 ?        00:00:00 ora_lg01_test

These are the log writer worker processes, for which the minimal amount is equal to the amount public (more...)

UKOUG Technology Day

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We have organized a UKOUG Technology Summit in Leeds on 16th May.

It’s really a small Conference!

This is available to UKOUG Members and will cost 1 SIG Pass – even Bronze memberships come with 1 SIG pass, so all members could attend at no cost.
Non-members can pay to attend, but you should take out a Bronze Membership instead as it’s about the same price!

Come along, network with your peers, and listen to (more...)

Stop password for user accounts expiring on Exadata

Depending on how the Oracle Exadata Machine was setup, the password for user accounts can expire thus requiring the password to be changed.

This has the knock on effect of the crontab not accessible and more importantly jobs do not run:

[oracle@v1ex1dbadm01 ~]$ crontab -l

Authentication token is no longer valid; new one required
You (oracle) are not allowed to access to (crontab) because of pam configuration.
[oracle@v1ex1dbadm01 ~]$

You can (more...)

Exadata troubleshooting easy with GetExaWatcherResults.sh

If you have for example a performance problem or a crash on your Exadata Machine and you need an overview about the machine then use the very powerful tool „GetExaWatcherResults.sh“ which based on the data of Exawatcher.

GetExaWatcherResults.sh give you a details about:

  • CPU utilization and details
  • IO Summary
  • and more

GetExaWatcherResults.sh will generate very good graphics and that is what I will show now.

How is the way to get these graphs?


 (more...)

A look into Oracle redo, part 5: the log writer writing

| Feb 27, 2018

This the the fifth blog in a series of blogposts about Oracle database redo. The previous blog looked into the ‘null write’ (kcrfw_do_null_write actually) function inside kcrfw_redo_write_driver, which does housekeeping like updating SCNs and posting processes if needed, this blog looks into what happens when the log writer is actually posted by a process or if public redo strand buffers have been written into. In part 3 of this blog series (the log writer working (more…)

Oracle Exadata Smart Flash Logging

What is Exadata Smart Flash Logging?

In an OLTP environment, it is crucial to have fast response times to redo log writes i.e. low latency.  When multiplexing redo logs for high availability i.e. to protect against hardware failure, redo log writes are only acknowledge when redo is written to all redo log members i.e when the slowest disk completes the write.  By this nature, whenever a disk slows down even (more...)