Altinity Blog

Five Ways to Handle as-of Queries in ClickHouse

A common use case in time series applications is to get the measurement value at a given point of time. For example, if there is a stream of measurements, one often needs to query the measurement as of current time or as of the same day yesterday and so on. Financial market data analysis and all sorts of monitoring applications are typical examples.

Databases have different ways to achieve this task and ClickHouse is not an exception here. In fact, ClickHouse offers at least 5 different approaches. In this article, we will review and compare them.

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Putting Things Where They Belong Using New TTL Moves

Multi-volume storage is crucial in many use cases. It helps to reduce storage costs as well as improves query performance by allowing placement of the most critical application data on the fastest storage devices. Monitoring data is a classic use case. The value of data degrades rapidly over time. The last day, last week, last month, and previous year data have very different access patterns, which in turn correspond to various storage needs.

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Altinity Novel Coronavirus Update

The COVID-19 outbreak has placed unprecedented stress on individuals and businesses worldwide. We would like to share a few words about how the Altinity team is dealing with this outbreak in the hope it may help your own planning.

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Altinity Stable Release update

We are delighted to announce that Altinity Stable Release is updated to The release includes several important bug fixes not present in the previous, and one compatibility fix that is important for future upgrades.

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Real-time Moving Average with ClickHouse Live Views

In data analytics, analysts often use moving averages. Moving averages help to smooth data series as well as identify long term trends. New Live View tables start to bring real-time capabilities to ClickHouse.

One of the applications of Live View tables is a calculation of real-time metrics on the event data. Readings from IoT sensors, price ticks from the stock exchange, or some metrics from your production servers are some of the examples of event data streams. ClickHouse can store all this data with a good compression ratio and excellent analytical query performance.

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ClickHouse February Community Events

US-based 2020 ClickHouse meetups started the year with a bang: two events in San Francisco and New York City. Here is a summary of the talks including links to presentation slides.

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ClickHouse Altinity Stable release update for Kafka users

Important notice for our beloved Apache Kafka users. We continue to improve Kafka engine reliability, performance and usability, and as a part of this entertaining process we have released Altinity Stable ClickHouse release. This release supersedes the previous stable release, and addresses following problems:

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New ClickHouse Altinity Stable Release

Welcome to the year 2020! New Year came and it's a good time to update your ClickHouse to the latest Altinity stable version which we are presenting today. As always, Altinity Stable is a version we know is good and recommended for production use. You can use a newer version in your lab environment to try the latest features.

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ClickHouse Cost-Efficiency in Action: Analyzing 500 Billion Rows on an Intel NUC

Jan 1, 2020
Cost-efficiency and performance are critical for big data analytics. For this reason a recent blog post from ScyllaDB guys caught our attention. They collected over 500 billion data points and were able to query it with 1B rows/sec query scan performance. The test rig was a beefy and expensive cluster: 83 n2.xlarge.x86 instances, 28 cores and 384RAM each. This is a nice demo of ScyllaDB cluster management. But looking at the numbers we realized it’s not very impressive as an example of efficient analytics. We can prove that using ClickHouse.

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Creating Beautiful Grafana Dashboards on ClickHouse: a Tutorial

Dec 28, 2019
Grafana is a popular tool to create dashboards of time series data. It features outstanding graphics, interactive displays that zoom in on data, and support for a wide range of data sources.  It turns out that one of those data sources is ClickHouse, and Grafana is a great way to visualize ClickHouse data. 

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Connecting Excel to ClickHouse using the Windows ODBC driver

Many years ago a wise customer once said, “every report wants to be an Excel spreadsheet when it grows up!” I have always had a soft spot for Excel--it’s one of the most useful programs that Microsoft ever released. To honor that long lost user this article will show how to bring joy to your ClickHouse reporting by pulling data into Excel.

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ClickHouse December Community Events

The year 2019 ended with a burst of ClickHouse community events in the US and Europe.  There were many great talks about ClickHouse from users exploring new use cases as well as operating at large scale.  Here is a quick rundown.

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