Infrastructure at your Service

Jérôme Dubar

A day of conferences with the Swiss Oracle User Group

Introduction

I’m not that excited with all these events arround Oracle technologies (and beyond) but it’s always a good place to learn new things, and maybe the most important, discover new ways of thinking. And regarding this point, I was not disappointed.

Franck Pachot: serverless and distributed database

Franck talked about scaling out, it means avoid monoliths. Most of the database servers are this kind of monoliths today. And he advises us to think microservices. It’s not so easy regarding the database component, but it could surely simplify the management of different modules through different developper teams. Achieving scaling out is also get rid of these old cluster technologies (think about RAC) and instead of that, adopt the “sharing nothing”: no storage sharing, no network sharing, etc.
It also means the need for db replication, and also scale of the writes: and that point is more complicated. Sharding is a key point for scaling out (put the associated data where the users resides).

I discovered the CAP theorem, a very interesting theory that shows us that there is actually no ultimate solution. You need to choose your priority: Consistancy and Availability, or Availability and Partition Tolerant or Consistency and Partiton Tolerant. Just remind to keep your database infrastructure adapted to your needs, a google-like infrastructure being probably nice but do you really need the same?

Kamran Aghayer: Transition from dba to data engineer

Times are changing. I knew that since several years, but now it’s like an evidence: as a traditional DBA, I will soon be deprecated. Old-school DBA jobs will be replaced by a lot of new jobs: data architect, data engineer, data analyst, data scientist, machine learning engineer, AI engineer, …

Kamran focused on Hadoop ecosystem and Spark especially when he needed to archive data from EXADATA to HADOOP (and explained how HADOOP manage data through HDFS filesystem and datanodes – sort of ASM). He used a dedicated connector, sort of wrapper using external tables. Actually this is also what’s inside the Big Data Appliance from Oracle. This task was out of the scope of a traditional DBA, as a good knowledge of the data was needed. So, traditionnal DBA is dead.

Stefan Oehrli – PDB isolation and security

Since Oracle announced the availability of 3 free PDBs with each container database, the interest for Multitenant increased.

We had an overview of the top 10 security risks, all about privileges, privilege abuse, unauthorized privileges elevation, platform vulnerability, sql injection, etc. If you’re already in the cloud with PAAS or DBAAS, risks are the same.

We had a presentation of several clues for risk mitigation:
– path_prefix: it’s some kind of chroot for the PDB
– PDB_os_credential (still bugs but…): concerns credentials and dbms_scheduler
– lockdown profiles: a tool for restricting database features like queuing, partitioning, Java OS access, altering the database. Restrictions working with inclusion or exclusion.

Paolo Kreth and Thomas Bauman: The role of the DBA in the era of Cloud, Multicloud and Autonomous Database

Already heard today that the classic DBA is soon dead. And now the second bullet. The fact is that Oracle worked hard to improve autonomous features during the last 20 years, and like it was presented, you realize that it’s clearly true. Who cares about extents management now?

But there is still a hope. DBA of tomorrow is starting today. As the DBA role actually sits between infrastructure team and data scientists, there is a way to architect your career. Keep a foot in technical stuff, but become a champion in data analysis and machine learning.

Or focus on development with opensource and cloud. The DBA job can shift, don’t miss this opportunity.

Nikitas Xenakis – MAA with 19c and GoldenGate 19c: a real-world case study

Hey! Finally, the DBA is not dead yet! Some projects still need technical skills and complex architecture. The presented project was driven by dowtime costs, and for some kind of businesses, a serious downtime can kill the company. The customer concerned by this project cannot afford more than 1h of global downtime.

We had an introduction of MAA (standing for Maximum Availability Architecture – see Oracle documentation for that).

You first need to estimate:
– the RPO: how much data you can afford to loose
– the RTO: how quick you’ll be up again
– the performance you expect after the downtime: because it matters

The presented infrastructure was composed of RHEL, RAC with Multitenant (1 PDB only), Acitve Data Guard and GoldenGate. The middleware was not from Oracle but configured to work with Transparent Application Failover.

For sure, you still need several old-school DBA’s to setup and manage this kind of infrastructure.

Luiza Nowak: Error when presenting your data

You can refer to the blog from Elisa USAI for more information.

For me, it was very surprising to discover how a presentation can be boring, confusing, missing the point just because of inappropriate slides. Be precise, be captivating, make use of graphics instead of sentences, make good use of the graphics, if you want your presentation to have the expected impact.

Julian Frey: Database cloning in a multitenant environment

Back to pure DBA stuff. Quick remind of why we need to clone, and what we need to clone (data, metadata, partial data, refreshed data only, anonymised data, etc). And now, always considering GDPR compliance!

Cloning before 12c was mainly done with these well known tools: rman duplicate, datapump, GoldenGate, dblinks, storage cloning, embedded clone.pl script (didn’t heard about this one before).

Starting from 12c, and only if you’re using multitenant, new convenient tools are available for cloning: PDB snapshot copy, snapshot carousel, refreshable copy, …

I discovered that you can duplicate a PDB without actually putting the source PDB in read only mode: you just need to put your source PDB in begin backup mode, copy the files, generate the metadata file and create the database with resetlogs. Nice feature.

You have to know that cloning a PDB is native with multitenant, a database being always a clone of something (at least an empty PDB is created from PDB$seed).

Note that Snapshot copy of a PDB is limited for some kind of filesystems, the most known being nfs and acfs. If you decide to go for multitenant without actually having the option, don’t forget to limit the maximum of PDB in your CDB settings. It’s actually a parameter: max_PDBs. Another interesting feature is the possibily to create a PDB from a source PDB without the data (but tablespace and tables are created).

Finally, and against all odds, datapump is still a great tool for most of the cases. You’d better still consider this tool too.

Conclusion

This was a great event, from great organizers, and if pure Oracle DBA is probably not a job that makes younger people dream, jobs dealing with data are not planned to disappear in the near future.

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Jérôme Dubar
Jérôme Dubar

Consultant