mirror of
https://github.com/Expand-sys/CCash
synced 2025-12-17 00:22:14 +11:00
35 lines
No EOL
2.9 KiB
Markdown
35 lines
No EOL
2.9 KiB
Markdown
[PREVIOUS PAGE](user_side.md) | [NEXT PAGE](../building.md)
|
|
|
|
# Implementation Features
|
|
## [Parallel Hashmap](https://github.com/greg7mdp/parallel-hashmap)
|
|
<!-- memory vs database -->
|
|
<!-- and while changes arent made on the basis of speed alone it does seem to fit the problem better as we only need to save every `n` minutes/on close. -->
|
|
<!-- phmap vs std hash map -->
|
|
#### STD vs phmap
|
|
this parallel hashmap implementation is the basis of CCash, its where all the user data is stored, compared to the STD's `std::unordered_map<T>` its much faster, this, multi threading support, and more can be found in the [writeup](https://greg7mdp.github.io/parallel-hashmap/).
|
|
#### Scalability
|
|
below is `GetBal()` being called where `x` axis grows with # of users reaching 10 million users, `y` axis is time in ns. The name given is random between 0 and max users at that time as to provide more accurate results.
|
|
.png)
|
|
as the graph demonstrates, regardless of size `GetBal()` remains consistent at ~39ns on my 3700x single threaded.
|
|
## [xxHash](https://github.com/Cyan4973/xxHash)
|
|
xxhash is used for both hashing of passwords for storage aswell as the usernames for indexing the phmap, its speed is ridiculous at faster then `memcpy` rates of Gb/s.
|
|
## [Base64](https://github.com/aklomp/base64)
|
|
base64 decoding is required for Basic Auth so I used this clean and fast solution found [here](https://github.com/aklomp/base64) which uses SIMD if available.
|
|
## [Simdjson](https://github.com/simdjson/simdjson)
|
|
simdjson was the fastest JSON parsing I could find, its used for request parsing.
|
|
## [Drogon webframework](https://github.com/an-tao/drogon)
|
|
at the time of making this doc Drogon is the 3rd fastest web framework as per [this](https://www.techempower.com/benchmarks/#section=data-r20&hw=ph&test=composite) sites metric of measuring web frameworks, it also has multi threading support.
|
|
## Sparse saving
|
|
#### Saving on close
|
|
when the program is interupted with CONTROL + C it will save before closing the webserver, **it will not however save during a crash**.
|
|
#### Auto Saving
|
|
every `n` minutes, a configurable amount at launch, CCash will save.
|
|
#### Changes
|
|
for the above two cases, it will only save to disk if changes have been made since last save.
|
|
#### [Binary Encoding](https://github.com/chronoxor/FastBinaryEncoding)
|
|
saving is done using FBE, this slightly reduces file size compared to JSON and is much faster.
|
|
## Multi-threading support
|
|
considering phmap and drogon both massively benefit from being multi-threaded it seemed obvious that the entire program should be, this is enabled by default and manually settable at `MULTI_THREADED`. Below are some graphs visualizing the gain of doing so:
|
|
<!-- graph -->
|
|
## Backwards Compatible API
|
|
versioning is implemented by the endpoints path, for example `/v1`. Breaking changes will ideally be sparse and backwards compatability will be maintained, for example ideally API `v3` instance can still run `v1` endpoints. |