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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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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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Star Schema Bechmark: InfoBright, InfiniDB and LucidDB

In my previous rounds with DataWarehouse oriented engines I used single table without joins, and with small (as for DW) datasize (see,, Addressing these issues, I took Star Schema Benchmark, which is TPC-H modification, and tried run queries against InfoBright, InfiniDB, LucidDB and MonetDB. I did not …

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A review of Pentaho Solutions by Roland Bouman and Jos van Dongen

Pentaho Solutions

Pentaho Solutions, Business Intelligence and Data Warehousing with Pentaho and MySQL. By Roland Bouman and Jos van Dongen, Wiley 2009. Page count: about 570 pages. (Here’s a link to the publisher’s site.)

The book is big in part because it’s about a GUI tool, so there are the requisite number of screenshots (but not too many). It is structured into four parts, each on a different topic.

The first part is 4 chapters on getting started with Pentaho: from a quick-start through …

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Air traffic queries in MyISAM and Tokutek (TokuDB)

This is next post in series
Analyzing air traffic performance with InfoBright and MonetDB
Air traffic queries in LucidDB
Air traffic queries in InfiniDB: early alpha

Let me explain the reason of choosing these engines. After initial three posts I am often asked "What is baseline ? Can we compare results with standard MySQL engines ?". So there come MyISAM to consider it as base point to see how column-oriented-analytic engines are better here.

However, take into account, that for MyISAM we need to choose proper indexes to execute queries …

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Air traffic queries in InfiniDB: early alpha

As Calpont announced availability of InfiniDB I surely couldn't miss a chance to compare it with previously tested databases in the same environment.
See my previous posts on this topic:
Analyzing air traffic performance with InfoBright and MonetDB
Air traffic queries in LucidDB

I could not run all queries against InfiniDB and I met some hiccups during my experiment, so it was less plain experience than with other databases.

So let's go by the same steps:

Load data

InfiniDB supports MySQL's LOAD DATA statement and it's own colxml / cpimport utilities. As …

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