multiversion-concurrency-contro VS algebralang

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In my experiments with multithreaded software I simulate a bank where many bankaccounts are randomly withdrawn from and deposited to.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

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

I want to redesign the architecture of the async/await to be easier to understand. I want to use a state machine somehow.

I wrote an unrolled state machine for my async/await in Java. This models a simple async/await program and runs tasks on other threads - without locks. I use a design I call token ring parallelism, where threads take turns and are linked together in a ring structure.

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

I wrote a own lock free algorithm here that I use to do message passing between actor threads. My goal is high throughput performance and low latency.

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

With 11 threads (on a 12 core processor, deliberately left one core for Windows)

I then started writing a parser for a high level language and then code generation from the AST to the imaginary assembly. My interpreter is multithreaded and can send integers between interpreters. It is very early and doesn't do much.

Code is at https://github.com/samsquire/multiversion-concurrency-contro...

The high level language looks similar to Javascript except I tried to parse everything as an expression. I need to parse functions as expressions.

I was experimenting with Protothreads in C recently to try understand how it worked and I wrote a giant switch statement and a while loop in Java to simulate async/await. It would be interesting to do codegen for coroutines.

here's that giant switch statement and scheduler https://github.com/samsquire/multiversion-concurrency-contro...

One idea for a stackless design I had was to preallocate memory for each method call for a call to that function and avoid a stack altogether. This would allow coroutines between methods and avoid the function colour problem because everything is a coroutine.

Is there any communities for programming language developers? Where do all the language developers meet up and talk theory and implementation? I am on eatonphil's discord and we talk there.

One problem I am trying to understand how to solve is how you would write a multithreaded interpreter and language that allowed parallel interpretation similar to C# and Java. If the allocator is thread safe and you share an object pool between interpreters and you hash object equality by sourcecode, then you could send objects between threads with only a synchronization cost.

I believe Python has the problem that object identity is different in each subinterpreter so you need to marshall the data.

I experiment with programming language theory and designs as a hobby and one of my thoughts is that the core underlying problem of computing is an arrangement problem of a turing machine. Compiling is "planning what you shall do". Execution is "doing". We have the luxury of many ways of doing things in computing. But it all seems to lead to mess of poor understandability and complexity.

What am I trying to say? OOP inheritance hiarchy trees are limited and not what you really want to do to represent your problem. I want to define a situation or scenario and define what should happen in that scenario. This is where asynchronous programming and join calculus shines. I also like occam-pi's select statement and golang's select. I also feel every computing problem is the "expression problem" manifested. How do you associate behaviour (what to do) with a type (a situation)? And how do you define them so you don't have to reimplement all the previously existing behaviours with the new thing?

The next section shall be reductive.

Ultimately all loops, function application, methods, expressions, variables, classes, functions, lists, vectors, data structures, algorithms exist as "things" in the imagination of the developer's mind and the compiler. They don't exist in machine code.

We have a grid of memory locations and the arrangement of things in that grid is handled by a memory allocator. We also have references in this grid as pointers, which form a structure of their own. A turing machine.

Thinking of a type and behaviour as being solely one thing only at a time is inherently limiting. I often want to see different things "as" something else to talk about them in a slightly different approach. A vector or ArrayList of objects of multiple types but processed in the same approach, efficient compile time polymorphism.

This is kind of how I imagine object orientated development to really be about, I want to be capable of referring to an arbitrary selection of objects and define new behaviours or relations between the objects. Unfortunately most OOP ties imperative behaviour and stateful manipulation to data rather than modify exhibited behaviours of objects. Imagine being capable of organising and managing load balancers and draining them and devops architecture with code. A point and click GUI where I can right click a load balancer and click drain. (I don't mean code to bring them up or create them but to actually administrate them with OOP)

I think the expression problem is a core problem of modern computing and doesn't have an efficient solution.

We can decouple data structure, layout and algorithm. Unfortunately most programming languages couple data structure + layout (C) and OOP languages couple algorithm with layout. Functional programming languages I'm not sure about.

I called this idea of software mimicry as branching libraries in my ideas document (link in profile)

I've been working with C++ templates today with C++20 coroutines and multithreading and I am finding template instantiation very interesting. I've been late to come around to it.

This comment mentioned the insight that boxing and template instantiation are related. https://news.ycombinator.com/item?id=14764780

I am also working on a multithreaded programming language which looks similar to Javascript. I use an actor implementation that can send messages between threads.

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

One of my programming language designs is the idea that every line of code is a concurrent process and data flow is scheduled by topological sorting. Iteration is handled automatically for you. Every variable is actually a relation and algebraic definition of relations between processes. This is called algebralang. https://github.com/samsquire/algebralang

The idea is that you write the underlying insight into the problem as an expression of what you want to do and let the computer schedule the ordering or arrangement of operations to do it. It's a form of pattern matching on the state of things (objects in the system) and declaration of the desired result. This brings to mind the rete algorithm (expert systems) and differential dataflow.

I began designing a language that handled handled recursion and iteration as relations between variables which are topologically sorted to determine control flow.

Each function is a toplogical graph of stream functions so it is similar to a data flow language or reactive programming language. The goal is that you should express the critical insight of the algorithm to work out what to write and the code is not nested so there is very little tree structure.

Algebralang is rough notes on how it would appear.

https://github.com/samsquire/algebralang

Example programs in the repository are binary search, btrees, a* algorithm.

I wrote a multithreaded parallel actor interpreter in Java and it uses an invented assembly language which doesn't have a bytecode, it's just text.

I like the ideas behind ani language