thangchung

From You're not actually building microservices

So, are you building microservices? Take a look at a few of these symptoms, and decide for yourself:

• ❌ A change to one microservice often requires changes to other microservices
• ✅ Deploying one microservice requires other microservices to be deployed at the same time
• ❓ Your microservices are overly chatty
• ❌ The same developers work across a large number of microservices
• ✅ Many of your microservices share a datastore
• ✅ Your microservices share a lot of the same code or models

thangchung

In this gist I would like to describe an idea for GraphQL subscriptions. It was inspired by conversations about subscriptions in the GraphQL slack channel and different GH issues, like #89 and #411.

Conceptual Model

At the moment GraphQL allows 2 types of queries:

• query
• mutation

Reference implementation also adds the third type: subscription. It does not have any semantics yet, so here I would like to propose one possible semantics interpretation and the reasoning behind it.

thangchung

• JAVA : 1-4 MB
• C++ : 1 MB
• Python : 64 KB
• Golang : 2-4 KB
• Node.js : Single threaded and event driven

thangchung

Some of the Redis best practices content has moved

This content from this markdown file has moved a new, happier home where it can serve more people. Please check it out : https://docs.microsoft.com/azure/azure-cache-for-redis/cache-best-practices.

NOTE: Client specific guidance listed below is still valid and should still be considered. I will update this document once all content has been moved.

thangchung

public class CachePipelineBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
    {
        private readonly IDistributedCache cache;
        private readonly ILogger<SGUKAspNetCore> logger;

        public CachePipelineBehavior(
            IDistributedCache cache,
            ILogger<SGUKAspNetCore> logger)
        {
            Ensure.Argument.NotNull(cache, nameof(cache));

thangchung

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

thangchung

// A generic base repository which other repositories (if needed) can inherit from

public class BaseRepository<TEntity> : IEntityRepository<TEntity> where TEntity : class
    {
        internal DataContext context;
        internal DbSet<TEntity> dbSet;

        public BaseRepository(DataContext context)
        {
            this.context = context;

thangchung

kubectl get pods | grep Evicted | awk '{print $1}' | xargs kubectl delete pod

thangchung

--- PSQL queries which also duplicated from https://github.com/anvk/AwesomePSQLList/blob/master/README.md
--- some of them taken from https://www.slideshare.net/alexeylesovsky/deep-dive-into-postgresql-statistics-54594192

-- I'm not an expert in PSQL. Just a developer who is trying to accumulate useful stat queries which could potentially explain problems in your Postgres DB.

------------
-- Basics --
------------

-- Get indexes of tables

thangchung

>>> docker exec -it CONTAINERID /bin/sh
/app # telnet
/bin/sh: telnet: not found

/app # apk update
fetch http://dl-cdn.alpinelinux.org/alpine/v3.7/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.7/community/x86_64/APKINDEX.tar.gz
v3.7.0-243-gf26e75a186 [http://dl-cdn.alpinelinux.org/alpine/v3.7/main]
v3.7.0-229-g087f28e29d [http://dl-cdn.alpinelinux.org/alpine/v3.7/community]