python

Python multithreaded print statements delayed until all threads complete execution

by

I have a piece of code below that creates a few threads to perform a task, which works perfectly well on its own. However I’m struggling to understand why the print statements I call in my function do not execute until all threads complete and the print 'finished' statement is called. I would expect them to be called as the thread executes. Is there any simple way to accomplish this, and why does this work this way in the first place?

Which is the fastest way to extract day, month and year from a given date?

by

I read a csv file containing 150,000 lines into a pandas dataframe. This dataframe has a field, Date, with the dates in yyyy-mm-dd format. I want to extract the month, day and year from it and copy into the dataframes’ columns, Month, Day and Year respectively. For a few hundred records the below two methods work ok, but for 150,000 records both take a ridiculously long time to execute. Is there a faster way to do this for 100,000+ records?

Simplest async/await example possible in Python

by

I’ve read many examples, blog posts, questions/answers about asyncio / async / await in Python 3.5+, many were complex, the simplest I found was probably this one.
Still it uses ensure_future, and for learning purposes about asynchronous programming in Python, I would like to see an even more minimal example, and what are the minimal tools necessary to do a basic async / await example.

Django persistent database connection

by

I’m using django with apache and mod_wsgi and PostgreSQL (all on same host), and I need to handle a lot of simple dynamic page requests (hundreds per second). I faced with problem that the bottleneck is that a django don’t have persistent database connection and reconnects on each requests (that takes near 5ms).
While doing a benchmark I got that with persistent connection I can handle near 500 r/s while without I get only 50 r/s.