xela-trawets / net.distributedfilestorecache

NET distributed cache using a json file as the shared resourse with very fast Get

Net.DistributedFileStoreCache

This repo contains the Net.DistributedFileStoreCache library provides a .NET distributed cache that has two excellent features

• It can get cache values blistering fast – it only takes ~25 ns. to Get one entry in a cache containing 10,000 entries.
  • It can also read ALL 10,000 cache entries in ~85 ns. too.
• It uses a json file as the shared resource which makes it really easy to setup, and you don't need to setup / pay for a database for your cache.

The main downsides is its slower than the database-bases distributed cache libraries when updating the cache values. See Performance figures for more information.

The Net.DistributedFileStoreCache is an open-source library under the MIT license and a NuGet package. The documentation can be found in the GitHub wiki and see the ReleaseNotes.md file for details of changes.

Performance figures

I measure the performance of the FileStore cache String version by the excellent BenchmarkDotNet library. My performance tests cover both reads and writes of the cache on a cache that already has 100, 1,000 and 10,000 cached values in it.

Each key/value takes 37 characters and the size of the cache file are:

NumKeysValues	Cache file size
100	4.6 kb
1000	40.1 kb
10000	400.0 kb

BenchmarkDotNet=v0.13.1, OS=Windows 10.0.19043.1766 (21H1/May2021Update) Intel Core i9-9940X CPU 3.30GHz, 1 CPU, 28 logical and 14 physical cores .NET SDK=6.0.203 [Host] : .NET 6.0.7 (6.0.722.32202), X64 RyuJIT DefaultJob : .NET 6.0.7 (6.0.722.32202), X64 RyuJIT

Read times

Summary of the read side is:

• Reads a single cache value took ~25 ns at all levels of cache size evaluated at.
• Getting a Dictionary of ALL the cache key/values took ~80 ns at all levels of cache size evaluated at.

Method	NumKeysAtStart	Mean	Error	StdDev
GetKey	100	22.69 ns	0.367 ns	0.343 ns
GetAllKeyValues	100	84.12 ns	1.251 ns	1.170 ns
GetKey	1000	21.24 ns	0.322 ns	0.301 ns
GetAllKeyValues	1000	81.42 ns	1.104 ns	1.033 ns
GetKey	10000	24.28 ns	0.314 ns	0.278 ns
GetAllKeyValues	10000	81.36 ns	0.996 ns	0.932 ns

NOTE: I tried a read of a SQL Server database containing 200 entries with Dapper and a single took about 300 us.

Write times

Summary of the write side is:

• The time taken to add a cache value to cache goes up as the size of the cache is. This makes sense as unlike a database you are reading and then writing ALL the cache values into a file.
• The async versions are slower than the sync versions, but it does release a thread while reading and writing.

Method	NumKeysAtStart	Mean	Error	StdDev
AddKey	100	1,302.69 us	9.85 us	9.21 us
AddKeyAsync	100	1,664.47 us	32.51 us	34.79 us
AddKey	1000	1,673.28 us	25.60 us	23.95 us
AddKeyAsync	1000	2,267.81 us	45.10 us	42.18 us
AddKey	10000	7,898.67 us	172.10 us	507.46 us
AddKeyAsync	10000	8,922.15 us	178.30 us	307.57 us

NOTE: I tried a write of a SQL Server database containing 200 entries with Dapper and a single INSERT took about 1,000 us. but but the real time would be longer because the SQL needs to see if a entry with the given key already exists, in which case it would need to update the value of the existing entry.