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Displaying posts with tag: Insight for DBAs (reset)
Upcoming Webinar Wed 2/6: Percona Software News and Roadmap Update

Join Percona CEO Peter Zaitsev as he presents Percona Software News and Roadmap Update on Wednesday, February 6, 2019, at 11:00 AM PST (UTC-8) / 2:00 PM EST (UTC-5).

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Come and listen to Percona CEO Peter Zaitsev discuss what’s new in Percona open source software. Topics include Percona Server for MySQL and MongoDB, Percona XtraBackup, Percona Toolkit, Percona XtraDB Cluster and Percona Monitoring and Management.

During this …

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Upcoming Webinar Wed 1/30: Percona XtraDB Cluster: Failure Scenarios and their Recovery

Please join Percona’s Senior Technical Manager, Alkin Tezuysal, and Percona’s Percona XtraDB Cluster Lead, Krunal Bauskar as they present their talk, Percona XtraDB Cluster: Failure Scenarios and their Recovery on Wednesday, January 30th, 2019, at 8:00 AM PST (UTC-8) / 11:00 AM EST (UTC-5).

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Percona XtraDB Cluster (a.k.a PXC) is an open source, multi-master, high availability MySQL clustering solution. PXC works with your MySQL / …

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Upcoming Webinar Thurs 1/17: How to Rock with MyRocks

Please join Percona’s Chief Technology Officer, Vadim Tkachenko, as he presents How to Rock with MyRocks on Thursday, January 17th at 10:00 AM PDT (UTC-7) / 1:00 PM EDT (UTC-4).

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MyRocks is a new storage engine from Facebook and is available in Percona Server for MySQL. In what cases will you want to use it? We will check different workloads and when MyRocks is most suitable for you. Also, as for any new engine, it’s important to set it up and tune it properly. So, we will review the most important settings to pay attention to.

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Amazon Aurora Serverless – The Sleeping Beauty

One of the most exciting features Amazon Aurora Serverless brings to the table is its ability to go to sleep (pause) when idle. This is a fantastic feature for development and test environments. You get access to a powerful database to run tests quickly, but it goes easy on your wallet as you only pay for storage when the instance is paused.

You can configure Amazon RDS Aurora Serverless to go to sleep after a specified period of time. This can be set to anywhere between five minutes and 24 hours

For this feature to work, however, inactivity has to be complete. If you have so much as a single query or even maintain an idle open connection, Amazon Aurora Serverless will not be able to pause.

This means, for example, that pretty much any monitoring you may have enabled, including our own …

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Upcoming Webinar Wed 1/9: Walkthrough of Percona Server MySQL 8.0

Please join Percona’s MySQL Product Manager, Tyler Duzan as he presents Walkthrough of Percona Server MySQL 8.0 on Wednesday, January 9th at 11:00 AM PDT (UTC-7) / 2:00 PM (UTC-4).

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Our Percona Server for MySQL 8.0 software is the company’s free, enhanced, drop-in replacement for MySQL Community Edition. The software includes all of the great features in MySQL Community Edition 8.0. Additionally, it includes enterprise-class features from Percona made available free and open source. …

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Amazon RDS Aurora MySQL – Differences Among Editions

Amazon Aurora with MySQL Compatibility comes in three editions which, at the time of writing, have quite a few differences around the features that they support.  Make sure you don’t assume the newer Aurora 2.x supports everything in Aurora 1.x. On the contrary, right now Aurora 1.x (MySQL 5.6 based) supports most Aurora features.  The serverless option was launched for this version, and it’s not based on the latest MySQL 5.7.  However, the serverless option, too, has its own set of limitations

I found a concise comparison of what is available in which Amazon Aurora edition hard to come by so I’ve created one.  The table was compiled based mostly on documentation research, so if you spot some mistakes please let me know and I’ll make a correction.

Please keep in mind, this is expected to …

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MySQL 8 and The FRM Drop… How To Recover Table DDL

… or what I should keep in mind in case of disaster

To retrieve and maintain in SQL format the definition of all tables in a database, is a best practice that we all should adopt. To have that under version control is also another best practice to keep in mind.

While doing that may seem redundant, it can become a life saver in several situations. From the need to review what has historically changed in a table, to knowing who changed what and why… to when you need to recover your data and have your beloved MySQL instance not start…

But let’s be honest, only a few do the right thing, and even fewer keep that information up to date. Given that’s the case, what can we do when we have the need to discover/recover the table structure?

From the beginning, MySQL has used some external files to describe its internal structure.

For instance, if I have a schema named windmills and a table …

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Nondeterministic Functions in MySQL (i.e. rand) Can Surprise You

Working on a test case with sysbench, I encountered this:

mysql> select * from sbtest1 where id = round(rand()*10000, 0);
+------+--------+-------------------------------------------------------------------------------------------------------------------------+-------------------------------------------------------------+
| id   | k      | c                                                                                                                       | pad                                                         |
+------+--------+-------------------------------------------------------------------------------------------------------------------------+-------------------------------------------------------------+
|  179 | 499871 | 09833083632-34593445843-98203182724-77632394229-31240034691-22855093589-98577647071-95962909368-34814236148-76937610370 | 62233363025-41327474153-95482195752-11204169522-13131828192 |
| 1606 | 502031 | …
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MySQL High Availability: Stale Reads and How to Fix Them

Continuing on the series of blog posts about MySQL High Availability, today we will talk about stale reads and how to overcome this issue.

The Problem

Stale reads is a read operation that fetches an incorrect value from a source that has not synchronized an update operation to the value (source Wiktionary).

A practical scenario is when your application applies INSERT or UPDATE data to your master/writer node, and has to read it immediately after. If this particular read is served from another server in the replication/cluster topology, the data is either not there yet (in case of an INSERT) or it still provides the old value (in case of an UPDATE).

If your application or part of your application …

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What Happens If You Set innodb_open_files Higher Than open_files_limit?

The settings of MySQL configuration variables have a fundamental impact on the performance of your database system. Sometimes it can be a little tricky to predict how changing one variable can affect others, and especially when dealing with cases like the one I’ll describe in this post, where the outcome is not very intuitive. So here, we’ll look at what happens when you set innodb_open_files higher than the open_files_limit.

We can set the maximum number of open files in our MySQL configuration file using:

open_files_limit=10000

If this isn’t set, then the default – which is 5,000 in MySQL 5.7 – should be used.

See Sveta’s excellent blog post for an …

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