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Search Results for: large set group by

MySQL community set to meet at Percona Live London 2014

The countdown is on for Europe’s largest annual MySQL event, Percona Live London 2014. The two days of technical tutorials and sessions, November 3-4, will focus on the latest MySQL industry trends, news, best practices …

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Percona XtraDB Cluster – installation and setup webinar follow up Q&A

Thanks for all, who attended my webinar, I got many questions and I wanted to take this opportunity to answer them. Q: Even ntp has a delay of 0.3-0.4 between servers does that mean a …

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High availability for MySQL on Amazon EC2 – Part 2 – Setting up the initial instances

This post is the second of a series that started here. The first step to build the HA solution is to create two working instances, configure them to be EBS based and create a security …

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The 451 Group reports on TokuDB v3.0 for MySQL

Matt Aslett over at The 451 Group has written a Market Development report entitled “Tokutek delivers ACID transaction support with TokuDB version 3.0.” Get the full report and you can try out The 451 Group’s …

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Missing Data – rows used to generate result set

As Baron writes it is not the number of rows returned by the query but number of rows accessed by the query will most likely be defining query performance. Of course not all row accessed …

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Speeding up GROUP BY if you want aproximate results

Doing performance analyzes today I wanted to count how many hits come to the pages which get more than couple of visits per day. We had SQL logs in the database so It was pretty …

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Using GROUP BY WITH ROLLUP for Reporting Performance Optimization

Quite typical query for reporting applications is to find top X values. If you analyze Web Site logs you would look at most popular web pages or search engine keywords which bring you most of …

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PHP Large result sets and summary tables.

We’re working with web site preparing for massive growth. To make sure it handles large data sets as part of the process we work on generation test database of significant size as testing your application …

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Are larger buffers always better ?

Sometimes I see people thinking about buffers as “larger is always better” so if “large” MySQL sample configuration is designed for 2GB and they happen to have 16, they would simply multiply all/most values by …

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Group commit and real fsync

During the recent months I’ve seen few cases of customers upgrading to MySQL 5.0 and having serious performance slow downs, up to 10 times in certain cases. What was the most surprising for them is …

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