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Install ClickHouse on Ubuntu 20.04 - Step by step process to perform it

This article covers how to install ClickHouse on Ubuntu. Basically, ClickHouse is an open-source analytics database developed for big data use cases. 

Install of ClickHouse on Ubuntu involves a series of steps that includes adjusting the configuration file to enable listening over other IP address and remote access. 


Column-oriented databases store records in blocks grouped by columns instead of rows. 

By not loading data for columns absent in the query, column-oriented databases spend less time reading data while completing queries. 

As a result, these databases can compute and return results much faster than traditional row-based systems for certain workloads, such as OLAP.


Online Analytics Processing (OLAP) systems allow for organizing large amounts of data and performing complex queries. 

They are capable of managing petabytes of data and returning query results quickly. 

In this way, OLAP is useful for work in areas like data science and business analytics.


Aggregation queries are queries that operate on a set of values and return single output values. 

In analytics databases, these queries are run frequently and are well optimized by the database. 


Some aggregate functions supported by ClickHouse are:

1. count: returns the count of rows matching the conditions specified.

2. sum: returns the sum of selected column values.

3. avg: returns the average of selected column values.


Some ClickHouse-specific aggregate functions include:

1. uniq: returns an approximate number of distinct rows matched.

2. topK: returns an array of the most frequent values of a specific column using an approximation algorithm.


You can set up a ClickHouse database instance on your server and create a database and table, add data, perform queries, and delete the database.

You can start, stop, and check the ClickHouse service with a few commands.

To start the clickhouse-server, use:

$ sudo systemctl start clickhouse-server

The output does not return a confirmation.

To check the ClickHouse service status, enter:

$ sudo systemctl status clickhouse-server

To stop the ClickHouse server, run this command:

$ sudo systemctl stop clickhouse-server

To enable ClickHouse on boot:

$ sudo systemctl enable clickhouse-server

To start working with ClickHouse databases, launch the ClickHouse client. 

When you start a session, the procedure is similar to other SQL management systems.

To start the client, use the command:

$ clickhouse-client

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Monitoring squid proxy server with Nagios log server

This article will guide you on how to configure the #Nagios log server to use a #proxy server.

#Squid is a caching and forwarding #HTTP web proxy. It has a wide variety of uses, including speeding up a web server by caching repeated requests, #caching web, #DNS and other computer network #lookups for a group of people sharing network resources, and aiding security by filtering #traffic.

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How to install the Anaconda Python on Ubuntu

This article will guide you on how to install, setup, update, and uninstall Anaconda which involves a series of steps to install and setup the Anaconda environment.

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Steps to install Wraith on Ubuntu

This article will guide you on how to install Wraith on Ubuntu which requires adding Ruby, ImageMagick, and some other dependencies added to the system.

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Gradle Installation and Configuration on Linux

This guide will show the steps to install and configure Gradle on Linux and Windows.

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Performance graph problems in Nagios

This article will help to fix performance issues in Nagios when performance graphs does not display the correct data even though their checks return true performance data. 

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