jboner

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

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

mobilemind

# delete local tag '12345'
git tag -d 12345
# delete remote tag '12345' (eg, GitHub version too)
git push origin :refs/tags/12345
# alternative approach
git push --delete origin tagName
git tag -d tagName

rgl

bash -c 'while [[ "$(curl -s -o /dev/null -w ''%{http_code}'' localhost:9000)" != "200" ]]; do sleep 5; done'

# also check https://gist.github.com/rgl/c2ba64b7e2a5a04d1eb65983995dce76

cy6erGn0m

private fun <K, V> Map<K, V>.mergeReduce(other: Map<K, V>, reduce: (V, V) -> V = { a, b -> b }): Map<K, V> {
    val result = LinkedHashMap<K, V>(this.size() + other.size())
    result.putAll(this)
    other.forEach { e ->
        val existing = result[e.key]

        if (existing == null) {
            result[e.key] = e.value
        }
        else {

oza

YARN

1. General resource management layer on HDFS
2. A part of Hadoop

Spark

1. In memory processing framework

Spark on YARN

jeffsheets

@EnableWebSecurity
class ApiSecurityConfig extends WebSecurityConfigurerAdapter {
    @Inject
    void configureGlobal(AuthenticationManagerBuilder auth) {
        auth.inMemoryAuthentication()
                .withUser('svc_acct').password('somePassword').roles('FULL_ACCESS')
    }

    @Override
    protected void configure(HttpSecurity http) {

fitzoh

@EnableGateway
@SpringBootApplication
public class SpringCloudGatewayApplication {

    private final String cookieName = "beta_active";
    private final String headerName = "X-Beta-active";
    private final String betaActiveValue = "true";

    /**
     * They're in the beta if they have a cookie or request header set

thomasdarimont

timeout 40s /bin/bash -c "while ! httping -qc1 http://somehost:8080/app ; do sleep 1 ; done; echo OK" || echo TIMEOUT

If the service cannot be reached within 40s then TIMEOUT will be printed otherwise OK.