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Displaying posts with tag: Insight for DBAs (reset)
Webinar Thursday June 22, 2017: Deploying MySQL in Production

Join Percona’s Senior Operations Engineer, Daniel Kowalewski as he presents Deploying MySQL in Production on Thursday, June 22, 2017 at 11:00 am PDT / 2:00 pm EDT (UTC-7).

Register Now  MySQL is famous for being something you can install and get going in less than five minutes in terms of development. But normally you want to run MySQL in production, and at scale. This requires some planning and knowledge. So why not learn the best practices around installation, configuration, deployment and backup?

This webinar is a soup-to-nuts talk that will have you going from zero to hero in no time. It includes discussion …

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MySQL Triggers and Updatable Views

In this post we’ll review how MySQL triggers can affect queries.

Contrary to what the documentation states, we can activate triggers even while operating on views:

https://dev.mysql.com/doc/refman/5.7/en/triggers.html

Important: MySQL triggers activate only for changes made to tables by SQL statements. They do not activate for changes in views, nor by changes to tables made by APIs that do not transmit SQL statements to the MySQL server.

Be on the lookout if you use and depend on triggers, since it’s not the case for updatable views! We have reported a documentation bug for this but figured it wouldn’t hurt to mention this as a short blog post, too. The link to the bug in question is here:

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ICP Counters in information_schema.INNODB_METRICS

In this blog, we’ll look at ICP counters in the information_schema.INNODB_METRICS. This is part two of the Index Condition Pushdown (ICP) counters blog post series. 

As mentioned in the previous post, in this blog we will look at how to check on ICP counters on MySQL and Percona Server for MySQL. This also applies to MariaDB, since the INNODB_METRICS table is also available for MariaDB (as opposed to the Handler_icp_% counters being MariaDB-specific). We will use the same table and data set as in the previous post.

For simplicity we’ll show the examples on MySQL 5.7.18, but they …

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MariaDB Handler_icp_% Counters: What They Are, and How To Use Them

In this post we’ll see how MariaDB’s Handler_icp_% counters status counters (Handler_icp_attempts and Handler_icp_matches) measure ICP-related work done by the server and storage engine layers, and how to see if our queries are getting any gains by using them.

These counters (as seen in SHOW STATUS output) are MariaDB-specific. In a later post, we will see how we can get this information in MySQL and Percona Server. This investigation spun off from comments in Michael’s post about the new MariaDB dashboard in PMM. Comments are very useful, so keep them coming!

We can start by checking the corresponding documentation pages:

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Chasing a Hung MySQL Transaction: InnoDB History Length Strikes Back

In this blog post, I’ll review how a hung MySQL transaction can cause the InnoDB history length to grow and negatively affect MySQL performance.

Recently I was helping a customer discover why SELECT queries were running slower and slower until the server restarts (which got things back to normal). It took some time to get from that symptom to a final diagnosis. Please follow me on the journey of chasing this strange MySQL behavior!

Symptoms

Changes in the query response time can mean tons of things. We can check everything from the query plan to the disk performance. However, fixing it with a restart is less common. After looking at “show engine innodb status”, I noticed some strange lines:

Trx read view will not see trx with id >= 41271309593, sees < 41268384363
---TRANSACTION 41271309586, ACTIVE 766132 sec
2 lock struct(s), heap size 376, 0 row lock(s), undo log entries 1
... …
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Storing UUID and Generated Columns

A lot of things have been said about UUID, and storing UUID in an optimized way. Now that we have generated columns, we can store the decomposed information inside the UUID and merge it again with generated columns. This blog post demonstrates this process.

First, I used a simple table with one char field that I called uuid_char to establish a base case. I used this table with and without a primary key:

CREATE TABLE uuid_char (
uuid char(36) CHARACTER SET utf8 NOT NULL,
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
CREATE TABLE uuid_char_pk (
uuid char(36) CHARACTER SET utf8 NOT NULL,
PRIMARY KEY (uuid)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

I performed the tests on a local VM over MySQL 5.7.17 for 30 seconds, with only two …

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Percona Live 2017: Day Two Keynotes

Welcome to the second day of the Percona Live Open Source Database Conference 2017, and the second set of Percona Live keynotes! It’s a bit rainy outside today, but that isn’t bothering the Percona Live attendees (we’re all indoors learning about new open source technologies)!

Day two of the conference kicked off with another four keynote talks, all of which discussed issues and technologies that are addressed by open source solutions:

The Open Source Database Business Model is Under Siege

Paul Dix (InfluxData)

Paul Dix’s keynote may have ruffled a few feathers, as he looked at possible futures for the open …

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Better Than Linear Scaling

In this blog, we’ll look at how to achieve better-than-linear scaling.

Scalability is the capability of a system, network or process to handle a growing amount of work, or its potential to be enlarged to accommodate that growth. For example, we consider a system scalable if it is capable of increasing its total output under an increased load when resources (typically hardware) are added: https://en.wikipedia.org/wiki/Scalability.

It is often accepted as a fact that systems (in particular databases) can’t scale better than linearly. By this I mean when you double resources, the expected performance doubles, at best (and often is less than doubled).  

We can attribute this assumption to Amdahl’s law (https://en.wikipedia.org/wiki/Amdahl%27s_law), and later …

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How to Setup and Troubleshoot Percona PAM with LDAP for External Authentication

In this blog, we’ll look at how to setup and troubleshoot the Percona PAM authentication plugin.

We occasionally get requests from our support clients on how to get Percona Server for MySQL to authenticate with an external authentication service via LDAP or Active Directory. However, we normally do not have access to client’s infrastructure to help troubleshoot these cases. To help them effectively, we need to setup a testbed to reproduce their issues and guide them on how to get authentication to work. Fortunately, we only need to install Samba to provide an external authentication service for both LDAP and AD.

In this article, I will show you how to (a) compile and install Samba, (b) create a domain environment with Samba, (c) add users and groups to this domain and (d) get Percona Server …

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The mysqlpump Utility

In this blog, we’ll look at the

mysqlpump

 utility.

mysqlpump

 is a utility that performs logical backups (which means backing up your data as SQL statements instead of a raw copy of data files). It was added in MySQL Server version 5.7.8, and can be used to dump a database or a set of databases to a file and then loaded on another SQL server (not necessarily a MySQL server).

Its usage is similar to

mysqldump

, but it includes a new set of features. Many of the options are the same, but it was written from scratch to avoid being limited to

mysqldump

 compatibility. The Main Features Include:

  • To make the dump process faster, it allows parallel processing of databases and objects within databases. …
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