Sierpinsky

Sierpinsky Triangle A Sierpinsky trianlge looks like: The above example is not to much developed….but you will get the idea. A Siepinsky triangle can be constructed the following way: Draw a triangle and color it completely black In every black triganle you see in the image do the following Create a white triangle by choosing …

Recursive SQL in DB2

Problem Playing around in DB2 I wanted to know how to create a hiearchical query. This because I wanted to create view for explain plans, a bit resembling the explain plans which oracle provides. First step is understanding how to make the recursive SQL’s The setup: drop table relations; create table relations (id int, parent …

DIG

Whenever I need to do something concerning DNS resolving I resort to dig. Some examples: Getting the IP adres for maboc.nl: martijnmbos@penguin:~$ dig maboc.nl ; DiG 9.11.5-P4-5.1+deb10u3-Debian maboc.nl ;; global options: +cmd ;; Got answer: ;; ->>HEADERHEADERHEADERHEADER

Debian apt commands

I just installed a Debian machine. And since I’m a very longtime RedHat/Fedora man now I’m struggling with the commands to install stuff. Here are my notes: apt update Updates the meta-data and repositories apt upgrade Actually upgrades packages who need upgrading apt install <package> Installs a package apt list [package] Displays all packages known …

Session statistics

You can have a look at v$sesstat (joined with v$staname) to see the value of some statistics at this moment. What is a little more difficult to see is how statistics change over time. So I wrote a script for it. What it does: Gather all statistics, of one or all sessions, and put them …