Designing a connection pool for psycopg3
Posted by Daniele Varrazzo on 2021-01-17
Tagged as psycopg3, development
The psycopg2 pool is a pretty simple object, little more than... a pool ofopen connections, and I think it falls short in several ways:
- the top usability problem is the fact that it cannot be used as contextmanager;
- if a connection is broken it is not noticed it until it is used by a client;
- if minconn connections are already taken, a new one is created anddisposed of as soon as finished using, regardless of whether other clientsmay need it;
- if more than maxconn connections are requested the client will receivean error.
MySQL Connector/Python is a standardized database driver for Python platforms and development. Additionally, MySQL Connector/Python 8.0 supports the new X DevAPI for development with MySQL Server 8.0.
MicroPython is a lean and efficient implementation of the Python 3 programming language that includes a small subset of the Python standard library and is optimised to run on microcontrollers and in constrained environments. Python adapter for PostgreSQL. The psycopg3 adaptation system. Posted by Daniele Varrazzo on 2020-11-24 Tagged as psycopg3, development, news The adaptation system between Python objects and PostgreSQL types is at the core of psycopg2 and psycopg3. For most Unix systems, you must download and compile the source code. The same source code archive can also be used to build the Windows and Mac versions, and is the starting point for ports to all other platforms. Download the latest Python 3 and Python 2 source. Install the Python driver into your local Python environment by using the pip installer so that you can use the Python driver to connect to an SAP HANA database. We use cookies and similar technologies to give you a better experience, improve performance, analyze traffic, and to personalize content.
For psycopg3 I would like something better. I have read around, lookinginto other pool implementations to figure out what a well designed connectionpool ought to do (a very well thought one seems the Java HikariCP) andthese are a few ideas I'd like to work on: they are here for a feedback,before I jump into enthusiastically implementing the wrong thing...
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If you are new to selenium and browser automation, I recommend the course below.
Related course
Browser Automation with Python Selenium
Web Driver
To start a web browser, the Selenium module needs a web driver. Python interacts with the selenium web driver and the web driver interacts with the browser.
Download Python Driver Software
Supported browsers are:
- Chrome
- Firefox
- Internet Explorer
- Safari
- Opera
- PhantomJS (invisible)
To start a browser, you will need to corresponding web driver. The driver “ChromeDriver” is needed to start Chrome, “FirefoxDriver” for Firefox.
All drivers can be downloaded from: https://docs.seleniumhq.org/download/
Example code
Python will start and control the chromium browser using the code below:
You can change the browser by creating a different instance:
The first two lines in the above code will open the browser on the same computer, the others lines open the browser remotely: on a phone.
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Then open a webpage using the get() method: