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Displaying posts with tag: managed services (reset)
Case in Point: A Year of Customer Experience with Percona

In 2017 we have welcomed many new customers into the Percona fold. It’s always interesting to find out what challenges the Percona team helped them to address and how they chose their relationship with Percona. As unbiased champions of open source database software, our consultancy, support and managed services staff apply their expertise across a wide range of technologies. Here are just a few stories from the past year.

Scaling applications on Amazon RDS the right way

Specializing in on-demand transportation services, Grab needed a high-availability, high performing database engine to serve their rapidly growing application. Grab operates in over 30 densely populated …

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The Mechanics of High Availability

High availability is necessary for organizations to compete. This blog post shows the tools for for MySQL databases and how we can help configure and deploy.

The post The Mechanics of High Availability appeared first on Datavail.

MySQL may return results in non-deterministic order with ‘order by’

Whenever we want a query’s results sorted, you may think of using the clause “order by.” You are correct: most of the time, MySQL will return the results in expected order with “order by.”

Be careful, though. Sometimes MySQL may return results in the non-deterministic order even with “order by.”

Indeed, if a query is ordered by a non-unique column, it may return results in an unexpected order. I tested the below example on MySQL 5.1.73, 5.5.54 and 5.6.19 and got the same result. However, when I applied the same example on MySQL 5.7.17, it returned the results in an unexpected order differently.

Follow me step-by-step and see how MySQL returns results in a non-deterministic order. Step 1-4 is for MySQL 5.1.73, 5.5.54 and 5.6.19, Step 5 is for MySQL 5.7.17. After the example, I will explain the reason behind this output.

Step 1. Create the table as …

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Showing entries 1 to 3