Tag Archives: python
Sometimes there is a need to combine data from different columns into one string. For example,
SELECT CONCAT(first_name, ‘ ‘, last_name) FROM employees;
This doesn’t look too bad, but can quickly get out of hand, if you need to do something more complex than that. For example, let’s say, we also need to mention the salary here:
SELECT CONCAT(first_name, ‘ ‘, last_name, ‘ -‘, CAST(FORMAT(salary, 0) AS VARCHAR(10)), ‘ ‘, currency) FROM employees;
This preview shows a new feature for MariaDB 10.7 that was developed as a part of Google Summer of Code (MDEV-25015) by Alan Cueva, together with his mentor Vicențiu Ciorbaru.
…
Continue reading “10.7 preview feature: Python-like string formatting”
My first encounter with the gdb command duel was on some old IRIX about 15 years ago. I immediately loved how convenient it was for displaying various data structures during MySQL debugging, and I wished Linux had something similar. Later I found out that Duel was not something IRIX specific, but a public domain patch for gdb 4.6 written in ’93 by Michael Golan. Unfortunately, it never got into gdb (for licensing reasons, so I’ve heard). Now the gdb 8 is out, and the patch, obviously doesn’t apply. Instead of fixing the patch, I’ve re-implemented Duel in Python, using gdb Python API and the Arpeggio parser. …
Continue reading “Duel: gdb vs. linked lists, trees, and hash tables”
Anyone who has peeked inside a gdb manual knows that gdb has some kind of Python API. And anyone who has skimmed through has seen something called “Pretty Printing” that supposedly tells gdb how to print complex data structures in a nice and readable way. Well, at least I have seen that, but I’ve never given it much thought. Still, one day, when I was typing:
(gdb) p/t table->read_set->bitmap[0] @ (table->read_set->n_bits+7)/8
for the umpteenth time I asked myself, “why the heck not?”, and so it begun…
(more…) …
Continue reading “Making life prettier with gdb PrettyPrinting API”