multiversion-concurrency-control VS hyperapp

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In my experiments with multithreaded software I simulate a bank where many bankaccounts are randomly withdrawn from and deposited to.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.

Please check out https://github.com/jorgebucaran/hyperapp

The likely reason it never caught on, is that it has similar pitfalls as Backbone:

- manually attaching DOM elements to view controllers

- manually attaching child views

- models which have to be wired individually via .listenTo

- possibility of infinite loops if the events accidentally recurse

A better tiny alternative would be hyperapp[1] or even Preact, that has a similar bundle size.

[1] https://github.com/jorgebucaran/hyperapp

If they're focused on performance and bundle size, it's your chance to try some minimalistic exotic stuff like hyperapp (https://github.com/jorgebucaran/hyperapp) or mithril (https://mithril.js.org/) Just for fun

With a bit of a deadline (due to a mixture of procrastination and confidence that Vue would work) I needed something quick. I have also used Hyperapp in the past but that looks like a dead project right now (although arguably it has all the functionality you need so why keep developing it?).

I’m glad it left that impression! My thoughts have clarified a bit since I read that post, and I think what I describe is more declarative, like React. But the best places to read about it (for web devs) are in Elm!

There is also this new thing I found that seems to really lean into the core of what being functional means here: https://github.com/jorgebucaran/hyperapp

After a while, you see that basically all systems can be modeled as event-driven, functional systems. It’s a flexible model, and fits beautiful into web dev where the semantics are very clear: the system is the web app and events are clicks, keyboard events, asynchronous calls...

Hyperapp is 1kb.

- Hyperapp (https://github.com/jorgebucaran/hyperapp) - Preact - Svelte - React / Vue

I'll tell you what I've learnt from struggling with a bug that made me lose a couple of weeks. The application framework used in this post is Hyperapp, but I guess the same problem can be found in frameworks based on transforming the state of "Single Source of Truth" with pure functions (such as Elm, Redux, so on) if we use them in a wrong way.

Personally, I try my best to avoid bringing in dependencies as much as possible, and try to limit my exposure to only dependencies with low/shallow transitive dependency counts. Unfortunately, this is pretty hard, especially in corporate settings. What we need more of are the opposite of what we've been collectively praising: we need more monolithic packages. Case in point: lodash.template is currently vulnerable with no mitigation, even though lodash itself is not. That's just sloppy publishing practices. Esbuild is a great start over the webpack/babel maze of dependencies. There's a stdlib effort along those lines that hopefully would also help. There's a bunch of micro-frameworks that are used in production just fine and have little to no dependencies.