multiversion-concurrency-control VS CPython

The code is in this repository https://github.com/samsquire/multiversion-concurrency-control in MultiplexingThread.java and MultiplexProgramParser.java

https://github.com/samsquire/multiversion-concurrency-contro...

And I implemented a 3 way text diff with myers algorithm based on https://blog.jcoglan.com/2017/02/12/the-myers-diff-algorithm...

https://github.com/samsquire/text-diff

I implemented an eventually consistent mesh protocol that uses timestamps to provide last write wins

I think I lean towards per-thread sharding instead of mutex based or lock free data structures except for lockfree ringbuffers.

You can get embarassingly parallel performance if you split your data by thread and aggregate periodically.

If you need a consistent view of your entire set of data, that is slow path with sharding.

In my experiments with multithreaded software I simulate a bank where many bankaccounts are randomly withdrawn from and deposited to. https://github.com/samsquire/multiversion-concurrency-contro...

I get 700 million requests per second due to the sharding of money over accounts.

If you want some sample code to implement MVCC, I implemented MVCC in multithreaded Java as a toy example

https://github.com/samsquire/multiversion-concurrency-contro...

First read TransactionC.java then read MVCC.java

I wrote an unrolled switch statement in Java to simulate eager async/await across treads.

https://github.com/samsquire/multiversion-concurrency-contro...

The goal is that a compiler should generate this for you. This code is equivalent to the following:

   task1:

https://doc.rust-lang.org/book/ch16-00-concurrency.html

I've been working on implementing Java async/await state machine with switch statements and a scheduling loop. If the user doesn't await the async task handle, then the task's returnvalue is never handled. This is similar to the Go problem with the go statement.

https://github.com/samsquire/multiversion-concurrency-contro...

If your async call returns a handle and

yield value2++

https://github.com/samsquire/multiversion-concurrency-contro...

I am still working on allowing multiple coroutines to be in flight in parallel at the same time. At the moment the tasks share the same background thread.

I asked this stackoverflow question regarding C++ coroutines, as I wanted to use coroutines with a thread pool.

https://stackoverflow.com/questions/74520133/how-can-i-pass-...

This is very interesting. Thank you for submitting this and thank you for working on this.

I am highly interested in parallelism and high concurrency. I implemented multiversion concurrency control in Java.

https://github.com/samsquire/multiversion-concurrency-contro...

I am curious how to handle replication with high concurrency. I'm not sure how you detect dangerous reads+writes to the same key (tuples/fields) across different replica machines. In other words, multiple master.

I am aware Google uses truetime and some form of timestamp ordering and detection of interfering timestamps. But I'm not sure how to replicate that.

I began working on an algorithm to synchronize database records, do a sort, then a hash for each row where hash(row) = hash(previous_row.hash + row.data)

Then do a binary search on hashes matching/not matching. This is a synchronization algorithm I'm designing that requires minimal data transfer but multiple round trips.

The binary search would check the end of the data set for hash(replica_a.row[last]) == hash(replica_b.row[last]) then split the hash list in half and check the middle item, this shall tell you which row and which columns are different.

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Python is a versatile tool, and today we're delving into a practical use case that can simplify your daily routines. With the datetime module at your disposal, handling dates and times becomes a breeze, making it perfect for crafting accurate and dynamic product receipts. Whether you're a seasoned Python pro or just starting your coding journey, this article will guide you through each step with ease.

When working in Visual Studio Code (VS Code), create a new Python file for our music player project. It's helpful to have separate files for different parts of your project.

> It provides a meaningful performance improvement for at least one popular platform (realistically, on the order of 5%).

At first it will not provide a large boost, but it will set the foundations for larger gains in subsequent releases. They link a list of some proposed improvements already underway, with improvement estimates, at https://github.com/python/cpython/issues/115802

After that, with the basics of software engineering understood, I would move on to a wider use language, with a bigger ecosystem to employ, most likely Python. This would expose me to large system design / distributed systems and architectural challenges...

Have you ever felt like your photos needed a little extra touch to stand out? Well, get ready because we're about to learn a cool Python trick! We're going to take ordinary photos and turn them into awesome pencil sketches using Python and OpenCV. This will make your pictures look like they were drawn by hand!

Have you ever found yourself in a situation where you needed to convert a bunch of images into a PDF file quickly and efficiently? Imagine the convenience of converting a series of images from your recent trip into a single PDF album with just a few clicks. In this article, we will cover the process of building an Image PDF Converter App using Python. With the help of libraries like tkinter, os, and Python Imaging Library (PIL), we'll walk through the process of creating a powerful tool that can streamline this task for you.

If you've ever wanted to learn how to use Python or if you already know a bit and want to try something new, then you're in the right place! In this article, we'll show you step-by-step how to make your very own calculator using Python's Tkinter library, a renowned Python library for creating graphical user interfaces. Tkinter stands out for its simplicity, versatility, and widespread use in the Python community. It doesn't matter if you're a total beginner or an experienced coder looking for a fun project, we'll guide you through everything you need to know.

Pandas is an open source, BSD-licensed library providing high-performance, easy-to-use data structures and data analysis tools for the Python programming language.

Python for Windows bundles liblzma from this project, but it appears to be version 5.2.5 [0] vendored into the Python project's repo on 2022-04-18 [1], so that should be fine, right?

[0] https://github.com/python/cpython/blob/main/PCbuild/get_exte...

[1] https://github.com/python/cpython-source-deps/tree/xz