# SnowflakeIdx
[](https://hex.pm/packages/snowflake_idx) [](https://hexdocs.pm/snowflake_idx/)
SnowflakeIdx aims to provide atomicity even when called by multiple processes, while ensuring reasonably fast performance.
It is designed to be called without worrying about overload in performance-critical systems.
To achieve this, it utilizes erlang's atomics to ensure fast performance.
By default, Snowflake ID is an unsigned 64-bit integer and has the following structure:
```elixir
# snowflake_idx = | machine_id | timestamp | seq |
# (64) = | (10) | (42) | (12) |
```
## Note
In extreme scenarios where too many IDs are issued by multiple processes within 1 millisecond,
a Process.sleep(1) call is made to ensure atomicity. This can result in a degradation of throughput.
## Installation
If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `snowflake_idx` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:snowflake_idx, "~> 1.0"}
]
end
```
then run as
```sh
$ mix deps.get
```
## Usage
To generate a SnowflakeIdx, you can call it as follows:
```elixir
iex> machine_id = 10
iex> {:ok, ref} = SnowflakeIdx.init(machine_id)
iex> SnowflakeIdx.next_id(ref)
iex> SnowflakeIdx.extract_id(ref, uid)
```
## Benchmarks
It performs faster when called by a single process than in a race condition with multiple processes.
### parallel: 1
```elixir
$ mix run bench/bench.exs
Operating System: Windows
CPU Information: AMD Ryzen 5 3600 6-Core Processor
Number of Available Cores: 12
Available memory: 15.93 GB
Elixir 1.14.2
Erlang 25.0
JIT enabled: true
Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 0 ns
reduction time: 0 ns
parallel: 1
inputs: none specified
Estimated total run time: 35 s
Name ips average deviation median 99th %
System.os_time 13.89 M 72.02 ns ±65.13% 102.40 ns 102.40 ns
System.monotonic_time 10.34 M 96.68 ns ±25.08% 102.40 ns 102.40 ns
System.system_time 9.91 M 100.91 ns ±16.50% 102.40 ns 102.40 ns
SnowflakeIdx.extract_id 8.49 M 117.77 ns ±31.17% 102.40 ns 204.80 ns
SnowflakeIdx.next_id 2.44 M 409.98 ns ±122.80% 0 ns 1024 ns
Comparison:
System.os_time 13.89 M
System.monotonic_time 10.34 M - 1.34x slower +24.66 ns
System.system_time 9.91 M - 1.40x slower +28.89 ns
SnowflakeIdx.extract_id 8.49 M - 1.64x slower +45.75 ns
SnowflakeIdx.next_id 2.44 M - 5.69x slower +337.97 ns
```
### parallel: 2
```elixir
$ mix run bench/bench.exs
Operating System: Windows
CPU Information: AMD Ryzen 5 3600 6-Core Processor
Number of Available Cores: 12
Available memory: 15.93 GB
Elixir 1.14.2
Erlang 25.0
JIT enabled: true
Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 0 ns
reduction time: 0 ns
parallel: 2
inputs: none specified
Estimated total run time: 35 s
Benchmarking SnowflakeIdx.next_id ...
Benchmarking SnowflakeIdx.extract_id ...
Benchmarking System.system_time ...
Benchmarking System.os_time ...
Benchmarking System.monotonic_time ...
Calculating statistics...
Name ips average deviation median 99th %
System.os_time 13.88 M 72.02 ns ±65.57% 102.40 ns 102.40 ns
System.monotonic_time 10.27 M 97.41 ns ±25.87% 102.40 ns 102.40 ns
System.system_time 8.83 M 113.22 ns ±270.02% 0 ns 1024 ns
SnowflakeIdx.extract_id 7.13 M 140.32 ns ±42.92% 102.40 ns 204.80 ns
SnowflakeIdx.next_id 1.37 M 732.27 ns ±364.74% 0 ns 19456 ns
Comparison:
System.os_time 13.88 M
System.monotonic_time 10.27 M - 1.35x slower +25.39 ns
System.system_time 8.83 M - 1.57x slower +41.20 ns
SnowflakeIdx.extract_id 7.13 M - 1.95x slower +68.30 ns
SnowflakeIdx.next_id 1.37 M - 10.17x slower +660.25 ns
```
