Note: I have also some posts in dev.to: https://dev.to/franckpachot

I’ve blogged on Medium for about one year. Now that I’m back at dbi services and I’ll continue to blog there. Here is the RSS feed:

Note that I’m also there on Twitter and LinkedIn and happy to receive comments, feedback, and questions. And blog posts are also replicated at http://www.oaktable.net/ of course.

So…

*** TRACE CONTINUES IN https://blog.dbi-services.com/

For once, I was at a conference without being a speaker, but co-organizer. The idea came only 3 months ago at the Swiss PostgreSQL Users Group dinner organized by dbi services in Milan before the PostgreSQL Conference when Laetitia Avrot asked me if it would be possible to organize a meetup at CERN.

My answer was “yes” of course, but I had just resigned from CERN so it had to happen before February where I come back the consulting life at dbi-services. …

For a long time, I use tmux for my live demos because I can multiplex my screen between my laptop and the beamer, I can show several panes, and I can script my commands using send-keys. I also use tmux to keep a stateful work environment which I run on my Oracle Cloud always free tier Compute Instance, which is 100% free and 100% available, and 100% accessible

• 100% because even if you need to create a trial account with your credit card it is never charged and the free tier remains after the 30 days trial
• 100% available because…

3 months ago, when Larry Ellison announced the “Always Free Tier”, I posted a blog about its possibilities and limitation:

I used the ATP, ADW, and compute instances that I’ve created during that time and then did not expect any termination. But exactly 3 months later, the service is not available.

Autonomous Database

About the Autonomous Databases, I got the same as Dani Schider:

I can’t connect with SQL Developer Web

I can’t connect with sqlplus:

The current message about Oracle Database is: multi-model database. That’s not new. At the time of Oracle 9i, Object Oriented was the trend, with all the flexibility of polymorphism, but without the mess of unstructured data and without the inconsistency of NoSQL. Oracle added a datatype that can contain any datatype: SYS.ANYDATA. …

Sorry for this title, but that’s exactly the subject: this short stack gives me enough information to understand the issue, reproduce it, open a SR, talk with friends, find a workaround,…

A Friday afternoon story

Here is how this started, on a database just migrated from 11g:

Every hour a job is running, many sessions are blocked on library cache lock. As we are in RAC 19c, The Hang Manager detects this blocking situation and kills the culprit after a while. This was the first time I see it in action in real life. Killing is never good, but that’s better than letting all…

You should get there if you search for “ORA-12637: Packet receive failed” and “Docker”. Note that you can get the same error on old versions of VirtualBox and maybe other virtualized environments that do not correctly forward out-of-band data.

TL;DR: There are two workarounds for this:

• get out-of-band correctly handled with a recent version of your hypervisor, or by disabling userland-proxy in Docker
• disable out-of-band breaks usage by setting DISABLE_OOB=ON in sqlnet.ora (client and/or server)

But this post is also the occasion to explain a bit more about this.

Out Of Band breaks

You have all experienced this. You run a long query and want to cancel it. Sometimes, just hitting…

In a previous post I mentioned that I do not use pgbench to benchmark the platform. But when it comes to measuring client/server application, pgbench fully makes makes sense.

I initialize the pgbench schema with small data:

pgbench - initialize - init-steps=dtgvpf -h localhost -p 5432 -U postgres franck

And I run the pgbench builtin workload with does something like a TPC-B

tpcb-like builtin

pgbench --builtin tpcb-like --transactions 30000 --protocol=prepared --jobs=10 --client=10 -h localhost -p 5432 -U postgres franck

I run 30000 transactions there, from 10 threads. It runs for more than 4 minutes:

The rate is 1097 transactions per second with…