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Posts tagged ClickHouse
Altinity ClickHouse Operator for Kubernetes

Apr 9, 2019

When I was setting up my first ClickHouse clusters 3 years ago it was like a journey to an unknown world full of caveats. ClickHouse is very simple and easy to use but not THAT simple. Sometimes I dreamed that setting up the cluster would be as easy as making a cup of coffee. It took us a while to find the right approach, but finally our dreams came true. Today, we are happy to introduce ClickHouse operator for Kubernetes!

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A Magical Mystery Tour of the LowCardinality Data Type

Mar 27, 2019

Many ClickHouse features like LowCardinality data type seem mysterious to new users.  ClickHouse often deviates from standard SQL and many data types and operations do not even exist in other data warehouses. The key to understanding is that the ClickHouse engineering team values speed more than almost any other property. Mysterious SQL expressions often turn out to be 'secret weapons' to achieve unmatched speed.

In fact, the LowCardinality data type is an example of just such a feature. It has been available since Q4 2018 and was marked as production ready in Feb 2019, but still is not documented, magically appearing in some documentation examples. In this article we will fill the gap  by explaining how LowCardinality works, and when it should be used.

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ClickHouse and Python: Jupyter Notebooks

Feb 25, 2019
Jupyter Notebooks are an indispensable tool for sharing code between users in Python data science. For those unfamiliar with them, notebooks are documents that contain runnable code snippets mixed with documentation. They can invoke Python libraries for numerical processing, machine learning, and visualization. The code output includes not just text output but also graphs from powerful libraries like matplotlib and seaborn. Notebooks are so ubiquitous that it’s hard to think of manipulating data in Python without them.

ClickHouse support for Jupyter Notebooks is excellent. I have spent the last several weeks playing around with Jupyter Notebooks using two community drivers: clickhouse-driver and clickhouse-sqlalchemy. The results are now published on Github at https://github.com/Altinity/clickhouse-python-examples. The remainder of this blog contains tips to help you integrate ClickHouse data to your notebooks.

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ClickHouse Continues to Crush Time Series

Feb 14, 2019

In our previous articles we demonstrated that ClickHouse -- a general purpose analytics DB -- can easily compete with specialized DBMSs for time series data: TimescaleDB and InfluxDB. There were, however, certain queries, pretty typical for time series, where ClickHouse seemed at first glance to be at a disadvantage. The most notable example is returning the latest measurement for particular device. We will take this query and demonstrate how ClickHouse advanced features, namely materialized views and self-aggregating tables, can  dramatically improve performance.

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ClickHouse and Python: Getting to Know the Clickhouse-driver Client

Feb 1, 2019

Python is a force in the world of analytics due to powerful libraries like numpy along with a host of machine learning frameworks. ClickHouse is an increasingly popular store of data. As a Python data scientist you may wonder how to connect them. This post contains a review of the clickhouse-driver client.  It’s a solidly engineered module that is easy to use and integrates easily with standard tools like Jupyter Notebooks and Anaconda.  Clickhouse-driver is a great way to jump into ClickHouse Python connectivity.

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Field Report: Migrating from Redshift to ClickHouse

Jan 25, 2019

FunCorp is an international developer of entertaining Apps. The most popular is iFunny - a fun picture and GIF app that lets users to pass the time looking at memes, comics, funny pictures, cat GIFs, etc. Plus, users can even upload their own content and share it. The iFunny app has been using Redshift for quite some time as a database for events in backend services and mobile apps. We went with them because in the beginning there really weren’t any alternatives comparable in terms of cost and convenience. However, the public release of ClickHouse was a real game changer. We studied it inside and out, compared the cost and possible architecture, and this summer finally decided to try it out and see if we could use it. This article is all about the challenge Redshift had been helping us solve and how we migrated this solution to ClickHouse.

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Altinity Stable ClickHouse 18.14.15 Release Notice

Nov 28, 2018

Altinity is happy to introduce ‘Altinity stable’ ClickHouse release marking. Altinity stable releases undergo additional testing from our side, we carefully monitored community feedback for any issues, as well as operated such releases in some heavy loaded production systems.

That being said, Altinity announces ClickHouse 18.14.15 release as Altinity stable. Read more for release notes.

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ClickHouse Crushing Time Series

Nov 15, 2018

Once upon a time we spotted TSBS (https://github.com/timescale/tsbs) -- Time Series Benchmark Suite, started by InfluxDB engineers and polished to perfection by TimescaleDB team. The suite allows to compare apples-to-apples when testing different databases: it is a framework to generate test data, load it to different databases, run test queries, and collect statistics to analyse. We could not resist adding ClickHouse to the list of supported databases. It turned out that ClickHouse --- being a general purpose analytical DBMS -- stands very well against proven time series databases. Those benchmarks highlighted strengths and weaknesses of different technologies. Interested? Let’s dig into details.

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Autumn's Newsletter

Nov 5, 2018

It's been a while, but we promise we've been busy. Since our last update, ClickHouse grew up a lot, there were many new features and enhancements, some of them we reviewed in our blog, others are still waiting for somebody to tell a story about. In this newsletter you can find the latest updates.

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ClickHouse Meetup in Paris Recap

Oct 19, 2018

October for us started strong with a successful ClickHouse meetup in Paris. The purpose of the event was to talk about ClickHouse, an open-source column-store analytics DBMS – its features, roadmap, use cases, meet local ClickHouse users, hear talks from ClickHouse lead developer Alexey Milovidov, Altinity CTO Alexander Zaitsev and Paris ClickHouse users.

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Updates and Deletes in ClickHouse

Oct 16, 2018

It’s been two years already ago when ClickHouse development team published an excellent blog post “How to update data in ClickHouse”. In that old times ClickHouse supported only monthly partitions, and for mutable data structures, they suggested to use pretty exotic data structures. We were all waiting for a more convenient approach, and finally, it is there: ClickHouse now supports updates in deletes! In this article, we will see how it works.

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Using ODBC with Clickhouse

20 Sept 2018
This article shows different ways of how you can use ClickHouse in connection with other data sources to make queries use all of ClickHouse optimization features in order to make results come faster. Also, it is good practice when you have some infrastructure elements already linked to some other data sources or tools that supports ODBC.

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Case Study. AfterWords - Intelligent Customer Engagement

Aug 1, 2018
AfterWords is an intelligent customer engagement and survey system that delivers users transactional history and customer feedback to create actionable data to improve operations, sales and profitability.

In this article, our guest author Oleg Khozyainov shares his experience of using ClickHouse as part of work done for www.surveyafterwords.com

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Realtime replication from MySQL to ClickHouse in practice

July 2, 2018
Vladislav Klimenko from Altinity and Valery Panov from Ivinco presented a talk at HighLoad Siberia 2018 conference recently. They described the real problem that Ivinco faced and how it has been solved with migration of analytics from MySQL into ClickHouse using MySQL to ClickHouse replication. A few months ago we introduced clickhouse-mysql tool in our blog, and Ivinco was the first company we know that tried it and used it in production.

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