linux

dbakevlar's picture

Linux Scripting, Part IV- Scripting for Longevity

We’ve learned a lot about commands, utilities and how to create a script, but we need to discuss the importance of scripting for longevity.

What is Scripting for Longevity?  We have a tendency to focus on scripting to automate something WE might not want to perform manually, but avoid what we think might void our value.  We may try to ensure there is necessity for our role or our knowledge as we create scripts.  This can be built into the execution process, scheduling, arguments, pre-run or post-run steps.  This doesn’t make us an asset, but a liability and against what I call, “the Code of Conduct” when automating.

Questions

The questions you have to ask yourself as you script out solutions are:

martin.bach's picture

sqlldr, direct path loads and concurrency in 12.2 and later

In my previous post I showed you that Oracle’s SQL loader (sqlldr) utility has a built-in timeout of 30 seconds waiting for locked resources before returning SQL*Loader-951/ORA-604/ORA-54 errors and failing to load data. This can cause quite some trouble! Before showing you the enhancement in 12.2 and later, here is the gist of the previous post.

Concurrency in Oracle sqlldr 12.1 and earlier

To show you how sqlldr times out I need to simulate an exclusive lock on the table in sqlplus for example. That’s quite simple:

martin.bach's picture

sqlldr, direct path loads and concurrency in 12.1 and earlier

I have recently come across an interesting issue related to concurrent data loading into the Oracle database using sqlldr’s direct path mode. Although I investigated the situation on 12.1.0.2, I found that the same holds true in 19.4 as well when using the defaults. I reconstructed the case, although it is simplified a little to bring the point home.

The environment I used to put this post together is Oracle Restart 19.4.0 on Oracle Linux 7.6.

Test overview

For this test I am running concurrent sqlldr sessions to demonstrate the case. I am conscious of that fact that I could have used external tables, but then I wouldn’t have been able to write this post :)

Assume there’s a table named t2:

martin.bach's picture

Ansible tips’n’tricks: checking if a systemd service is running

I have been working on an Ansible playbook to update Oracle’s Tracefile Analyser (TFA). If you have been following this blog over the past few months you might remember that I’m a great fan of the tool! Using Ansible makes my life a lot easier: when deploying a new system I can ensure that I’m also installing TFA. Under normal circumstances, TFA should be present when the (initial) deployment playbook finishes. At least in theory.

As we know, life is what happens when you’re making other plans, and I’d rather check whether TFA is installed/configured/running before trying to upgrade it. The command to upgrade TFA is different from the command I use to deploy it.

I have considered quite a few different ways to do this but in the end decided to check for the oracle-tfa service: if the service is present, TFA must be as well. There are probably other ways, maybe better ones, but this one works for me.

martin.bach's picture

RBAL (ospid: nnn): terminating the instance due to error 27625 after patching Oracle Restart

I have come across an odd behaviour trying to patch an Oracle Restart environment to 12.1.0.2 January 2019. Based on a twitter conversation this isn’t necessarily limited to my patch combination, there might be others as well. I have used opatchauto to apply patch 28813884 to both RDBMS and GRID homes plus its corresponding OJVM (Java) patch. Before diving into details, this is the environment I have been working with:

Franck Pachot's picture

strace -k (build with libunwind)

strace -k (built with libunwind)

prints the stack trace with the system calls

PostgreSQL is Open Source and you may think that it is not necessary to trace the system calls as we can read the source code. But even there, strace is a really nice tool for troubleshooting a running process.

https://postgreslondon.org/speaker/dmitrii-dolgov/

Little disclaimer here: attaching strace to a running process may hang. Do not use it in production, except when this (small) risk is an acceptable way to troubleshoot a critical problem.

fritshoogland's picture

Getting rid of annoying, repetitive messages in /var/log/messages

The primary source of information regarding any change or issue on a linux system is the /var/log/messages file. I am often annoyed when a linux system is setup in such a way that certain messages are written to syslog with a high frequency swamping the messages file with information that is not important. The reason for my annoyance is that this makes it very hard to actually spot important information because you have to skip through a lot of lines before you find the important information, especially if you do not know for sure if there a message in the first place.

Please mind this blogpost is created on a Centos 7 server which uses rsyslog.

There are a couple of ways to manage this. The standard syslog way of managing this is the following, which can be found in /etc/rsyslog.conf:

martin.bach's picture

Learning Kubernetes: persistent storage with Minikube

As part of my talk at (the absolutely amazing) Riga Dev Days 2019 I deployed Oracle Restful Data Services (ORDS) in Minikube as my application’s endpoint. I’ll blog about deploying ORDS 19 in docker and running it on Kubernetes later, but before I can do so I want to briefly touch about persistent storage in Minikube because I saw it as a pre-requisite.

dbakevlar's picture

Linux Scripting, Part III

In the previous blog posts, we learned how to set up the first part of a standard shell script- how to interactively set variables, including how to pass them as part of the script execution. In this next step, we’ll use those to build out Azure resources. If you’re working on-premises, you can use this type of scripting with SQL Server 2019 Linux but will need to use CLI commands and SQLCMD. I will cover this in later posts, but honestly, the cloud makes deployment quicker for any business to get what they need deployed and with the amount of revenue riding on getting to market faster, this should be the first choice of any DBA with vision.

dbakevlar's picture

Remove Files with Force and Other Bad Ideas

Almost every Linux or Unix person has seen the help forum post from a novice looking for an answer to a frustrating problem and the arrogant fool that responds with “Just type in rm -rf / and it will fix the problem.” For anyone who is part of the “do no harm” technical community, this can make us wish for a way to revoke the arrogant fool’s privileges to the internet— permanently.

To prevent automated spam submissions leave this field empty.
Syndicate content