Author Archives: George Valentin Voina

Time is the new gold ! Why is important to have a life outside the job.

By | December 27, 2019

So what is tech twitter doing on Christmas ? Debating on if it’s good idea to work 40+ hours a week or you have to work more. Toxic tech CEOs, founders and VCs are saying you won’t make an impact to the world if you do not clock more than 40+ hours. The Silicon Valley… Read More »

#Banking is changing and we will have to change its meaning in the near future

By | December 27, 2019

All this started with a tweet by Chris Gledhill: I agree 100% with the idea that the whole idea of banking and what it is to be a bank will change completely in the next years. I just looked around what “traditional banks” do at this point, in this era of post 2008 crisis of… Read More »

#Jboss #Artemis AMQ153005: Unable to retrieve ${0} from JNDI. Creating a new ${1} named ${2} to be used by the MDB

By | December 17, 2019

This is a strange annoying warning that suddenly appeared after I upgraded to JBoss 7.4.2 and was completly flooding my output log. It looks like an warning due to a bad configuration that until version 7.4.2 was ignored. My log looked something like this: Of course the fact that somehow the warning message seems to… Read More »

#Oracle: ORA-02298: cannot validate "key" – parent keys not found

By | December 17, 2019

When trying to add a foreign key to a table sometimes the error ORA-02298 is thrown. Let’s have two tables a MyTable and a MyTableHistory connected by a historyid column from MyTable that points to the id column from MyTableHistory Try then to add add foreign key like: If we are in the case of… Read More »

Use #ELK stack to monitor #JBOSS application server

By | December 13, 2019

The ELK (ElasticSearch+LogStash +Kibana ) stack is maybe the best method to monitor your environment in a simple visually applying way. My task was to monitor the parameters of a Jboss/Wildfly application server where my enterprise application is hosted. There are several guides that describe how to deploy the basic stack, I am not going… Read More »

Migrating a #PostgreSQL database to a diferent PostgreSQL version or to a restrictive Postgres instance of cloud providers like #AWS-RDS

By | December 11, 2019

There are instances when one needs to migrate data from a Postgres database to a different PostgreSQL database version or even worse to a restrictive PostgreSQL instance of cloud providers like #AWS-RDS. When migrating to a different version of Postgres after you used to run on a frozen production version for long time it may… Read More »

#SQL to remove duplicate rows from a table in #Oracle

By | December 11, 2019

Sometimes you need to add by hand a primary key on a table that initially did not have any constraint. Most of the time you will run into the issue of having duplicate rows, so first we must make sure there are no duplicate rows. Duplicate rows are the rows that have duplicates in the… Read More »

#OpenSSH private keys with old PEM format

By | December 11, 2019

Starting from openssh 7.8 the default format for private keys has changed from PEM to OpenSSH: That means that private keys generated with the referenced command: (ssh-keygen -t rsa -b 4096) are no longer generated as PEM format. Lot’s of online services do not accept this format yet CircleCI, GitHub are some of the services… Read More »

Acronyms of a #VC for #fintech people

By | December 8, 2019

When you start reading lots of VC tweets and blog posts is easy to get confused by the deluge of acronyms they use. The following are the basic definitions for the most important acronyms. CAC = Customer acquisition cost TAC = Total acquisition cost LTV= Lifetime value TAM = Total available market YoY growth =… Read More »

Disable core dumps in #Linux

By | December 11, 2019

Systemd doesn’t completely control whether core dumps are made or not. It mainly determine where such dumps go, and whether they should take up space or not. It may prevent some user space core dumps, but not all. With “Storage=none”, they can still occur and are registered by journald, but they don’t take up disk… Read More »