spsc_queue
multiversion-concurrency-control
spsc_queue | multiversion-concurrency-control | |
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2 | 19 | |
35 | 66 | |
- | - | |
10.0 | 7.3 | |
over 4 years ago | 5 months ago | |
C++ | Java | |
BSD 2-clause "Simplified" License | - |
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spsc_queue
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Low latency queues in Rust ecosystem
I've been researching how low latency I can get with Rust and if there's anything already built. If I limit the question only to SPSC queues, it looks like crossbeam-channel is the most performant one and needs around 20ns per item. In comparison to e.g. https://github.com/Deaod/spsc_queue with almost 1ns/item (the linked queue is not implemented in Rust and only used as an example of what's physically possible). I don't see why we couldn't have something like that in the Rust ecosystem and am wondering if there are any other places to look for perf structures like that, other than Github or crates.io (or they live under a different tag). Also if I would go for a c++ queue, can somebody share the perf impact of calling it from Rust? Haven't done that yet.
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A collection of lock-free data structures written in standard C++11
Should be benchmarked against ->
https://github.com/Deaod/spsc_queue
If proven faster OK.. If not.. Well.. back to the drawing board.
multiversion-concurrency-control
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Statelines - an idea for representing asynchronicity elegantly
The code is in this repository https://github.com/samsquire/multiversion-concurrency-control in MultiplexingThread.java and MultiplexProgramParser.java
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CRDT-richtext: Rust implementation of Peritext and Fugue
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
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A collection of lock-free data structures written in standard C++11
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.
- How to get started?
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The “Build Your Own Database” book is finished
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
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Let's write a setjmp
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:
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Structured Concurrency Definition
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
- Are there any languages with transactions as a first-class concept?
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Small VMs and Coroutines
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-...
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Hctree is an experimental high-concurrency database back end for SQLite
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.
What are some alternatives?
tlaplus - TLC is a model checker for specifications written in TLA+. The TLA+Toolbox is an IDE for TLA+.
electric - Local-first sync layer for web and mobile apps. Build reactive, realtime, local-first apps directly on Postgres.
glibc - GNU Libc
tree-flat - TreeFlat is the simplest way to build & traverse a pre-order Tree in Rust
marisa-trie - MARISA: Matching Algorithm with Recursively Implemented StorAge
pybktree - Python BK-tree data structure to allow fast querying of "close" matches
abseil-cpp - Abseil Common Libraries (C++)
gring - Golang circular linked list with array backend
sync
plurid-data-structures-typescript - Utility Data Structures Implemented in TypeScript
multiversion-concurrency-contro
pvfmm - A parallel kernel-independent FMM library for particle and volume potentials