4 years ago, Alexey Milovidov published “Yandex Opens ClickHouse”, a historic blog post that opened up a new era in analytical databases. Since then we consider June 15 as the birthday of ClickHouse. ClickHouse is our beloved child that grows up and matures very rapidly. Like any normal kid, it has some bad habits and a lot of “character.” We teach it and are happy to see how it progresses. Birthdays are a time for presents. For ClickHouse’s 4th birthday we prepared ...Read More
ClickHouse external dictionaries are a “ClickHouse way” to handle multi-dimensional schema. ClickHouse Dictionaries Explained was the very first article in the Altinity blog three years ago. ClickHouse has improved significantly since then, and dictionaries have achieved a new level of utility. In this article, I will explain two new cool ClickHouse features that completely change the way how dictionaries can be used. Change in a good sense, of course.Read More
Mutable data is generally unwelcome in OLAP databases. ClickHouse is no exception to the rule. Like some other OLAP products, ClickHouse did not even support updates originally. Later on, updates were added, but like many other things they were added in a “ClickHouse way.”
Even now, ClickHouse updates are asynchronous, which makes them difficult to use in interactive applications. Still, in many use cases users need to apply modifications to existing data and expect to see the effect immediately. Can ClickHouse do that? Sure it can.Read More
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.Read More
We are delighted to announce that Altinity Stable Release is updated to 126.96.36.199. The release includes several important bug fixes not present in the previous 188.8.131.52, and one compatibility fix that is important for future upgrades.Read More
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 packet.com 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.
Altinity is glad to announce the certification of 184.108.40.206 ClickHouse release as Altinity Stable. This is a minor upgrade over the previous 19.11.8 release, but we recommend users install it before moving to more recent releases due to a few important fixes and changes.Read More
CoreOS introduced operators for Kubernetes in 2016. A Kubernetes Operator is an application that integrates into Kuberentes and manages other applications. It significantly simplifies deployment and management of cloud native apps by leveraging application specific operational knowledge. Since then operators have been developed for many applications in Kubernetes, including some databases. As a result, operators became a successful pattern for managing cloud native applications.Read More
It is already more than 3 years since ClickHouse surprisingly popped up from inside the Yandex labs and moved to open source. Since then it grew up from an ugly duckling, that was sometimes not that easy to deal with, to a mature well established analytical database, used at companies from small startup to Fortune 500 enterprises all around the world. Today, ClickHouse has made one more important step, it moved from the Yandex cradle to its own new home at Github!Read More
The recent Moscow ClickHouse meetup was quite a big event, as expected. ClickHouse is very popular in Russia and usage has penetrated widely among companies here. 450 people registered, and around 200 showed up at the Yandex conference hall on Thursday evening. Some attendees flew over from other cities and countries. The first talk started at 7pm, and the last clickhousers left the building shortly after midnight, full of ideas from interesting talks and conversations.Read More
July 10, 2019
Modern analytical databases would not exist without efficient data compression. Storage gets cheaper and more performant, but data sizes typically grow even faster. Moore’s Law for big data outperforms its analogy in hardware. In our blog we already wrote about ClickHouse compression (https://www.altinity.com/blog/2017/11/21/compression-in-clickhouse) and Low Cardinality data type wrapper (https://www.altinity.com/blog/2019/3/27/low-cardinality). In this article we will describe and test the most advanced ClickHouse encodings, which especially shine for time series data. We are proud that some of those encodings have been contributed to ClickHouse by Altinity.
This article presents an early preview of new encoding functionality for ClickHouse release 19.11. As of the time of writing, release 19.11 is not yet available. In order to test new encodings ClickHouse can be built from source, or a testing build can be installed. We expect that ClickHouse release 19.11 should be available in public releases in a few weeks.Read More