Showing entries 1 to 10 of 751
10 Older Entries »
Displaying posts with tag: Insight for DBAs (reset)
Low Value in range_optimizer_max_mem_size Might Cause Full Table Scan

Although how range_optimizer_max_mem_size operates is explained in the official doc, it’s not a well-known variable and surely not a variable you need to modify under most circumstances. But from time to time we get some performance tickets related to this.

What problem does this variable cause if it is not properly sized? Let’s find out with an example!

Given the following table definition:

CREATE TABLE `joinit` (
  `i` int(11) NOT NULL AUTO_INCREMENT,
  `s` varchar(64) DEFAULT NULL,
  `t` time NOT NULL,
  `g` int(11) NOT NULL,
  PRIMARY KEY (`i`)
) ENGINE=InnoDB AUTO_INCREMENT=2490316 DEFAULT CHARSET=latin1

With ~2M rows

select count(*) from joinit ;
+----------+
| count(*) |
+----------+
|  2097152 |
+----------+

With the default value of  range_optimizer_max_mem_size = 8388608, the …

[Read more]
The MySQL Clone Wars: Plugin vs. Percona XtraBackup

Large replication topologies are quite common nowadays, and this kind of architecture often requires a quick method to rebuild a replica from another server.

The Clone Plugin, available since MySQL 8.0.17, is a great feature that allows cloning databases out of the box. It is easy to rebuild a replica or to add new nodes to a cluster using the plugin. Before the release of the plugin, the best open-source alternative was Percona XtraBackup for MySQL Databases.

In this blog post, we compare both alternatives for cloning purposes. If you need to perform backups, Percona XtraBackup is a better tool as it supports compression and incremental backups, among other features not provided by the plugin. The plugin supports compression only for network transmission, not for storage.

But one of the plugin’s strong points is simplicity. …

[Read more]
MySQL 8.0.22: SHOW PROCESSLIST Version 2 – Now Available From PERFORMANCE_SCHEMA

The “SHOW PROCESSLIST” command is very famous and very useful for MySQL DBAs. It will help you to understand the ongoing thread activities and their current states. By default, the “show processlist” output details will be collected from the thread manager, and it needs the global mutex. From MySQL 8.0.22, we have an alternative way to get the process details from the PERFORMANCE_SCHEMA. It doesn’t need the global mutex. 🙂

Note: We also have the non-blocking SYS schema views “processlist” and “x$processlist”, which provide more complete information than the SHOW PROCESSLIST statement and the INFORMATION_SCHEMA.PROCESSLIST and PERFORMANCE_SCHEMA.PROCESSLIST. But, we can’t integrate this with the “SHOW PROCESSLIST” command.

In this blog, I am going to explain the complete details about the new processlist implementation using PERFORMANCE_SCHEMA.

“SHOW PROCESSLIST” Using Thread …

[Read more]
MySQL Backup and Recovery Best Practices

In this blog, we will review all the backup and restore strategies for MySQL, the cornerstones of any application. There are a few options, depending on your topology, MySQL versions, etc. And based on that, there are some questions we need to ask ourselves to make sure we make the right choices.

How many backups we need to keep safe, or what’s the best retention policy for us?

This means the number of backups to safeguard, whether local or remote (external fileserver, cloud). The retention policy can be daily, weekly, or monthly, depending on the free space available.

What is the Recovery Time Objective?

The Recovery Time Objective (RTO) refers to the amount of time that may pass during a disruption before it exceeds the maximum allowable threshold specified in the Business Continuity Plan.

The key question related to RTO is, “How quickly must the data on this system be restored?”

What is …

[Read more]
Streaming MySQL Backups with Percona XtraBackup – Another Alternative

Today we are going to present you with another way to make a database copy between servers using our Percona XtraBackup utility.  What is the difference with many others existing on the web?  Not many, but they are interesting in terms of performance and availability.

We will combine the xbstream utility with the power of pigz and socat, to take advantage of the multi-processing in the case of having multiple processors, and at the same time, reduce the use of network bandwidth in cases where this component is a bottleneck.  So let’s explain each component:

socat: This stands for SOcket CAT. It is a utility for data transfer between two addresses.

What makes socat so versatile is the fact that an address can represent a network socket, any file descriptor, a Unix domain datagram or stream …

[Read more]
Updated MySQL OSMetrics Plugins

It has been some time since I have posted updates to my plugins.  After the initial version, I decided to split the plugins into categories of metrics.  This will allow users to choose whether they want to install all of the plugins or only select ones they care about.

Since the installation process is unfamiliar to many users, I also expanded the instructions to make it a little easier to follow.  Moreover, I added a Makefile.

I have also reformatted the output of some plugins to be either horizontal or vertical in orientation.  There is still more work to do in this area as well.

Where to Get The MySQL Plugins

You can get the plugins from GitHub at https://github.com/toritejutsu/osmetrics but they will have to be compiled from source.  As mentioned above, you can choose whether to install all of them or one by …

[Read more]
TAM Enterprise Experiences – Data Encryption

In previous TAM Enterprise Experiences posts, we have outlined typical aspects of utilizing MySQL in an Enterprise environment. One thing we have not yet covered is the topic of database encryption, both from the standpoint of business requirements as well as some of the more technical aspects of encryption.

In this post, we will cover:

  • Common enterprise compliance requirements
  • Types of MySQL encryption
  • Choosing the right encryption
  • Vault

Common Compliance Requirements

Beyond the obvious security concerns with sensitive data, most enterprise businesses also need to meet various compliance requirements, with the compliance requirement(s) dependent on the country the business is located in, the type of business, and the type of data being stored. Note that in all cases, the onus is on the business to protect the data based on these compliance requirements. Some of …

[Read more]
Google Cloud Platform: MySQL at Scale with Reliable HA Webinar Q&A

Earlier in November, we had a chance to present the “Google Cloud Platform: MySQL at Scale with Reliable HA.” We discussed different approaches to hosting MySQL in Google Cloud Platform with the available options’ pros and cons. This webinar was recorded and can be viewed here at any time. We had several great questions, which we would like to address and elaborate on the answers given during the webinar.

Q: What is your view on Cloud SQL High Availability in Google Cloud?

A: Google Cloud SQL provides High Availability through regional instances. If your Cloud SQL database is regional, it means that there’s a standby instance in another zone within the same region. Both instances (primary and standby) are kept synced through synchronous replication on the persistent …

[Read more]
Percona XtraBackup: Introducing Support For Storage Class in xbcloud

A lot of elements take part in a good backup strategy. Two of them are:

  • Where to store your backups – Never on the same server. Preferable not in the same datacenter. Ideally far enough so you can restore in case of a natural disaster (region flood, extended local power outage, etc…).
  • Retention period – The longer, the better.

Those points relate directly to costs. Storing a backup on an off-site facility cost money. Keeping the backups available to fulfill your retention period policy costs money.

The main cloud providers have different layers of storage often called Storage Class. Each layer has its own particularities and policies, but they come with an important factor – Cost!

We are happy to announce that starting at …

[Read more]
Redesign of –lock-ddl-per-table in Percona XtraBackup

MySQL 5.7, alongside other many improvements, brought bulk load for creating an index (WL#7277 to be specific), which made ADD INDEX operations much faster by disabling redo logging and making the changes directly to tablespace files. This change requires extra care for backup tools. To block DDL statements on an instance, Percona Server for MySQL implemented LOCK TABLES FOR BACKUP. Percona XtraBackup (PXB) uses this lock for the duration of the backup. This lock does not affect DML statements.

MySQL 5.7 doesn’t have an option to block an instance against DDL and to allow all MDL’s. Thus, Percona XtraBackup has also implemented –lock-ddl-per-table. Before we go into other details, let’s understand how –lock-ddl-per-table works up to now:

  1. PXB …
[Read more]
Showing entries 1 to 10 of 751
10 Older Entries »