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```
SPARK_WORKER_INSTANCES=3 SPARK_WORKER_CORES=2 ./sbin/start-slaves.sh
```
This will launch three worker instances on each node. Each worker instance will use two cores.
Also it is possible to manually start workers and connect to Spark’s master node. To do this use command:
```
./bin/spark-class org.apache.spark.deploy.worker.Worker spark://IP:PORT
```

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Recall that cluster write throughput is directly proportional to the number of nodes N, 
and inversely proportional to the number of replicas RF. If a single node writes 15,000 rows per second, 
then you would expect a 5 node cluster writing 3 replicas will be roughly 15,000 * N / RF or 25,000 rows/s.
[Source](https://www.datastax.com/blog/2011/05/understanding-hinted-handoff-cassandra-08)

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java -jar {JAR} --spring.config.location={CONFIG_FILE_LOCATION}

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package com.aegis.controller;
import java.util.HashMap;
import java.util.Map;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

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### CURL and binary data
1. Fill the http body with the content of a file:
```
curl --request POST --data-binary "@/tmp/your_file_path/" {URL}
```

2. Send files as multipart/form-data
```
curl -F 'img_avatar="@/tmp/your_file_path/" {URL}
```

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In one of my projects, I wanted to create fat jar. I used `maven-assembly-plugin` but when I ran the jar, I got the 
runtime error. That was because akka needed `refrenece.conf` and in the process of building jar, this file was not add to 
output assembly. Shade plugin solved my problem:
```
 <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <version>3.1.0</version>
    <executions>
        <execution>

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Inspired by dannyfritz/commit-message-emoji

See also gitmoji.

Commit type	Emoji
Initial commit	🎉 :tada:
Version tag	🔖 :bookmark:
New feature	✨ :sparkles:
Bugfix	🐛 :bug:

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import slick.jdbc.H2Profile.api._

import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.Await
import scala.concurrent.duration.Duration

object Main {

  case class User(username:String, password: String,id:Long=0)
  class Users(tag: Tag) extends Table[User](tag , "users") {

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class Dfa {

  var states = Seq.empty[State]
  var finalStates = Seq.empty[State]
  var currentState : State = null
  var input:String=""
  val transition = new Transition
  val transitionMap = transition.transitionMap

  def states( block: => Seq[State] ): Dfa = {

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package main

type FuncIntInt func(int) int

func memorized(fn FuncIntInt) FuncIntInt {
	cache := make(map[int]int)

	return func(input int) int {
		if val, found := cache[input]; found {
			println("Read from cache")