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Displaying posts with tag: olap (reset)
ClickHouse: One Year!

In this blog, we’ll look at ClickHouse on its one year anniversary.

It’s been a year already since the Yandex team released ClickHouse as open source software. I’ve had an interest in this project from the very start, as I didn’t think there was an open source analytical database that could compete with industry leaders like Vertica (for example).

This was an exciting year for ClickHouse early adopters. Let’s look at what it accomplished so far.

ClickHouse initially generated interest due to the Yandex name – the most popular search engine in Russia. It wasn’t long before jaw-dropping responses popped up: guys, this thing is crazy fast! Many early adopters who tried ClickHouse were really impressed.

Fast doesn’t mean convenient …

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Installing the Open Source Xavier XML/A client on the Jedox Premium OLAP Suite

Jedox is a software vendor that specializes in OLAP services and solutions. The company has been around quite a while and is probably best known for their PALO MOLAP engine and the matching add-in for Microsoft Excel.

Jedox' flagship product, Jedox Premium comprises the Palo MOLAP engine, API's, a REST server, and ETL server, and client tools. It also comes with a MDX interpreter and a XML for Analysis server. An interesting tidbit is that the MDX layer is not considered native, and Jedox' own clients use a lower level API, or address it via the REST service.

In this blog post I will explain how to install and configure the Open Source browser-based ad-hoc query and analysis tool Xavier to use it with Jedox. A video of the process is embedded below:

Here's a …

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Installing the Open Source Xavier XML/A client on icCube OLAP suite

IcCube is a relatively young Swiss company specialized in creating OLAP software products. Their flagship product is the icCube Suite, providing an OLAP server, an XML for Analysis service, and a bunch of browser-based client tools for modeling cubes and dimensions, and for querying, reporting and visualizing OLAP data.

When you download the icCube trial edition, you'll get a java web server with an already deployed instance of the icCube java web application. This set-up makes it super-easy to install any browser-based third party XML/A clients for icCube.

In this blog post I want to provide you with the instructions to deploy the ad-hoc OLAP query tool called Xavier directly on your icCube server. This allows you to do ad-hoc, drag 'n drop style reporting on any data exposed by the icCube server.

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Need a Mondrian .WAR? Check out XMondrian.

To whom it may concern, this is a quick note to bring the xmondrian project to your attention. Introduction: Open Source OLAP, Mondrian, Pentaho, and JasperSoftMondrian is the open source OLAP engine. Mondrian provides:

  • a multi-dimensional view of a relational database (ROLAP)
  • a MDX query engine
  • Clever, advanced caching layers to speed up OLAP query performance (making it a MOLAP/ROLAN hybrid i.e., HOLAP)
  • Standards compliant OLAP data access by providing XML for Analysis (XML/A) and …
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MDX: "Show Parents" - Redux: A generic and systematic MDX query transformation to obtain the lineage of each member

A couple of months ago I wrote about how you can use the MDX functions Ancestors() and Ascendants to retrieve the full lineage of members. (See: "MDX: retrieving the entire hierarchy path with Ancestors()".)

As you might recall, the immediate reason to write about those functions was to find a pure MDX solution to implement the "Show Parents" / "Hide Parents" functionality offered by OLAP cube browsers. To recap, developers of MDX-based pivot tables face a challenge when rendering the result of a query like this:

SELECT CrossJoin(
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MDX: retrieving the entire hierarchy path with Ancestors()

A couple of days ago I wrote about one of my forays into MDX land (Retrieving denormalized tabular results with MDX). The topic of that post was how to write MDX so as to retrieve the kind of flat, tabular results one gets from SQL queries. An essential point of that solution was the MDX Ancestor() function.

I stumbled upon the topic of my previous blogpost while I was researching something else entirely. Creating flat tables and looking up individual ancestors is actually a rather specific application of a much more general solution I found initially. Pivot tables and the "Show Parents" functionalityGUI OLAP tools typically offer a pivot table query interface. They let you drag and drop measures and dimension items, like …

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MySQL webinar: ‘Introduction to open source column stores’

Join me Wednesday, September 18 at 10 a.m. PDT for an hour-long webinar where I will introduce the basic concepts behind column store technology. The webinar’s title is: “Introduction to open source column stores.”

What will be discussed?

This webinar will talk about Infobright, LucidDB, MonetDB, Hadoop (Impala) and other column stores

  • I will compare features between major column stores (both open and closed source).
  • Some benchmarks will be used to demonstrate the basic performance characteristics of the open source column stores.
  • There will be a question and answer session to ask me anything you like about column stores (you can also ask in the …
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Using Flexviews – part one, introduction to materialized views

If you know me, then you probably have heard of Flexviews. If not, then it might not be familiar to you. I’m giving a talk on it at the MySQL 2011 CE, and I figured I should blog about it before then. For those unfamiliar, Flexviews enables you to create and maintain incrementally refreshable materialized views.

You might be asking yourself “what is an incrementally refreshable materialized view?”. If so, then keep reading. This is the first in a multi-part series describing Flexviews.

You can find part 2 of the series here:

The output of …

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Intro to OLAP

This is the first of a series of posts about business intelligence tools, particularly OLAP (or online analytical processing) tools using MySQL and other free open source software. OLAP tools are a part of the larger topic of business intelligence, a topic that has not had a lot of coverage on MPB. Because of this, I am going to start out talking about these topics in general, rather than getting right to gritty details of their performance.

I plan on covering the following topics:

  1. Introduction to OLAP and business intelligence. (this post)
  2. Identifying the differences between a data warehouse, and a data mart.
  3. Introduction to MDX queries and the kind of SQL which a ROLAP tool must generate to answer those queries.
  4. Performance challenges …
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New OLAP Wikistat benchmark: Introduction and call for feedbacks

I've seen my posts on Ontime Air traffic and Star Schema Benchmark got a lot of interest

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