The Oracle Database

This page contains a list of all my posts dealing with the Oracle database in one way or another.

Generating Table DDL in Oracle Database

Generating table DDL is a common requirement. Unfortunately it’s not quite common enough for me to remember the syntax by heart, so this post serves as a reference to myself how to do this. Hopefully it saves you a few minutes, too. I used Oracle SQLDeveloper Command-Line (SQLcl) version: 22.1.1.0 build: 22.1.1.131.0820 for this post,…

DOAG 2021 gems: DBMS_XPLAN.COMPARE_PLANS

The most excellent #DOAG2021 conference ended last week. I have attended quite a few presentations and took lots of notes. I particularly enjoyed Conner McDonald’s presentation about 25 years of tips and techniques. One of these tips prompted this blog post ;) Turns out I have only seen a change to DBMS_XPLAN in passing. Its…

The performance story that didn’t turn out as one: a case of or-expansion and how the database mitigated the problem on its own

Recently I had a bit of time to study the effect of an optimizer query transformation, the so-called or-expansion in Oracle 19c. I thought there might be performance implications with statements using bind variables transformed in this way. My limited testing suggests that isn’t necessarily the case as the optimiser is remarkably resilient. Still I…

Deploying I/O intensive workloads in the cloud: Oracle Automatic Storage Management (ASM)

Over the past month I wrote a few posts about deploying I/O intensive workloads in the cloud. Using standard Linux tools, mainly Logical Volume Manager (LVM) I tried to prevent certain pitfalls from occurring. Although I’m a great fan of LVM and RAID (and their combination), there are situations where LVM/Software RAID aren’t part the…

Resolving slight niggles of Enterprise Manager Express 19c

This page, should I remember I wrote it, hopefully addresses the slight niggles I have with Oracle Enterprise Manager Express. I always forget how to solve these and it takes me a minute to remember. I hope this page helps me jump start my memory. If you have any additional niggles to report please do…

Deploying I/O intensive workloads in the cloud: mdadm (aka Software) RAID

The final part of my “avoiding pitfalls with Linux Logical Volume Manager” (LVM) series considers software RAID on Oracle Linux 8 as the basis for your LVM’s Physical Volume (PV). It’s still the very same VM.Standard.E4.Flex running Oracle 19.12.0 on top of Oracle Linux 8.4 with UEK6 (5.4.17-2102.203.6.el8uek.x86_64) I used for creating the earlier posts.…

Deploying I/O intensive workloads in the cloud: LVM RAID

I recently blogged about a potential pitfall when deploying the Oracle database on LVM (Logical Volume Manager) with its default allocation policy. I promised a few more posts detailing how to potentially mitigate the effect of linear allocation in LVM. The post was written with the same Oracle 19.12.0 database deployed to Oracle Linux 8.4…

Deploying I/O intensive workloads in the cloud: don’t fall for the LVM trap

I have been assessing the “best” storage option for Oracle databases deployed on Infrastructure as a Service (IaaS) VMs quite a few times now. As part of the discussion DBAs often pose the question whether using Linux’s Logical Volume Manager (LVM) is a good choice for data files. It can be, depending on the circumstances…

Do I really have to set resource limits for Oracle in systemd unit files?

TL;DR: it is very much required to set resource limits in systemd unit files. If you’d like to learn more about potential directives to put into a unit file, please have a look at the earlier post I wrote for a more thorough explanation. I also wrote a short post about a potential unit file…

Using systemd to start an Oracle single instance database when booting

I don’t work with systemd frequently enough to remember its syntax and other intricacies so I thought I’d just write down how to start an Oracle 19c single instance database via systemd on Oracle Linux 8.4. Primarily so I can look it up later when I need it, but isn’t that the reason many bloggers…

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