Mean
The "average" number; found by adding all data points and dividing by the number of data points.
The "average" number; found by adding all data points and dividing by the number of data points.
Tuesday, April 24, 2018
Sunday, April 22, 2018
Kafka partitions
- Each topic has one or more partitions
- The no of topics in kafka is dependent on the circumstances in which Apache Kafka is intended to be used.It can be configurable
- A partition is the basis for which kafka can
- Scale
- Become fault-tolerant
- Achieve higher level of throughput
- Each partitions are maintained at at-least one or more brokers
Overview of S3
- Interface that you can use to store and retrieve any amount of data, at any time, from anywhere on the web
- Is an object store, not a file system.
- Highly scalable, reliable, fast, inexpensive data storage infrastructure
- Uses eventually consistency model
Markdown Cheat Sheet (Jupyter Notebook)
Headers
# H1
## H2
### H3
#### H4
##### H5
###### H6
Alternatively, for H1 and H2, an underline-ish style:
Alt-H1
======
Alt-H2
------
Overview of Pig
- Apache Pig is a high-level platform for creating programs that run on Apache Hadoop.
- The language for this platform is called Pig Latin.
- Pig can execute its Hadoop jobs in MapReduce, Apache Tez, or Apache Spark
Local mode
- In local mode, Pig runs in a single JVM and access the local file system. This mode is suitable only for small data sets but not for big data sets.
- We can set this local mode execution type by using “X” or “exectype” option. To run in local mode, set the option to local
Shell script
- Interprets user command which are directly entered by the user or which are read from a file called shell script/program
- Shell script are interpreted
- Typical operations performed by shell scripts include file manipulation, program execution, and printing text
Overview of Flume
Flume
- Distributed data collection service
- Gets streaming event data from different sources
- Moves large amount of log data from many different sources to a centralized data store.
Note: We cannot use flume to get relational data
Span vs div (CSS)
div is a block element, span is inline.
This means that to use them semantically, divs should be used to wrap sections of a document, while spans should be used to wrap small portions of text, images, etc.
For example:
<div>This a large main division, with <span>a small bit</span> of spanned text!</div>
Display block vs inline vs inline-block
Sample html
<!DOCTYPE html>
<html>
<head>
<style>
.floating-box {
display: inline-block;
width: 150px;
height: 75px;
margin: 10px;
border: 3px solid #73AD21;
}
.after-box {
border: 3px solid red;
}
</style>
</head>
<body>
<h2>The New Way - using inline-block</h2>
<div class="floating-box">Floating box</div>
<div class="floating-box">Floating box</div>
<div class="floating-box">Floating box</div>
<div class="floating-box">Floating box</div>
<div class="floating-box">Floating box</div>
<div class="floating-box">Floating box</div>
<div class="floating-box">Floating box</div>
<div class="floating-box">Floating box</div>
<div class="after-box">Another box, after the floating boxes...</div>
</body>
</html>
CSS for td in the same line (Angular 2)
Html
<table id="table_id"><tr><td>testtesttesttest</td>
<td>testtesttesttest</td>
</tr>
</table>
</table>
React Function vs Class Component
React has 2 Components
Function Component:
- Simplest form of react component
- It receives an object of properties and returns JSX (which looks like html)
Saturday, April 14, 2018
Simple demo using Kafka
Start ZooKeeper
1 | bin/zookeeper-server-start.sh config/zookeeper.properties |
Start telnet
1 | telnet localhost 2181 |
Create topic
1 | bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic test |
List kafka Topics
1 | bin/kafka-topics.sh --list --zookeeper localhost:2181 |
Install kafka
Steps for installing Kafka
- You need to setup a Java virtual machine on your system before you can run Apache Kafka properly.
- We can install OpenJDK Runtime Environment 1.8.0 using YUM:
sudo yum install java-1.8.0-openjdk.x86_64
- Validate your installation with:
java -version
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