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Percona Server for MySQL 5.7.17-11 is now available

February 3, 2017 - 12:32pm

Percona announces the GA release of Percona Server for MySQL 5.7.17-11 on February 3, 2017. Download the latest version from the Percona web site or the Percona Software Repositories.

Based on MySQL 5.7.17, including all the bug fixes in it, Percona Server for MySQL 5.7.17-11 is the current GA release in the Percona Server for MySQL 5.7 series. Percona’s provides completely open-source and free software. Find release details in the 5.7.17-11 milestone at Launchpad.

New Features:
  • Percona Server for MySQL has implemented support for per-column VARCHAR/BLOB compression for the XtraDB storage engine. This also features compression dictionary support, to improve compression ratio for relatively short individual rows, such as JSON data.
  • Kill Idle Transactions feature has been re-implemented by setting a connection socket read timeout value instead of periodically scanning the internal InnoDB transaction list. This makes the feature applicable to any transactional storage engine, such as TokuDB, and, in future, MyRocks. This re-implementation is also addressing some existing bugs, including server crashes: #1166744, #1179136, #907719, and #1369373.
Bugs Fixed:
  • Logical row counts for TokuDB tables could get inaccurate over time. Bug fixed #1651844 (#732).
  • Repeated execution of SET STATEMENT ... FOR SELECT FROM view could lead to a server crash. Bug fixed #1392375.
  • CREATE TEMPORARY TABLE would create a transaction in binary log on a read-only server. Bug fixed #1539504 (upstream #83003).
  • Using per-query variable statement with subquery temporary tables could cause a memory leak. Bug fixed #1635927.
  • Fixed new compilation warnings with GCC 6. Bugs fixed #1641612 and #1644183.
  • A server could crash if a bitmap write I/O error happens in the background log tracking thread while a FLUSH CHANGED_PAGE_BITMAPS is executing concurrently. Bug fixed #1651656.
  • TokuDB was using wrong function to calculate free space in data files. Bug fixed #1656022 (#1033).
  • CONCURRENT_CONNECTIONS column in the USER_STATISTICS table was showing incorrect values. Bug fixed #728082.
  • Audit Log Plugin when set to JSON format was not escaping characters properly. Bug fixed #1548745.
  • InnoDB index dives did not detect some of the concurrent tree changes, which could return bogus estimates. Bug fixed #1625151 (upstream #84366).
  • INFORMATION_SCHEMA.INNODB_CHANGED_PAGES queries would needlessly read potentially incomplete bitmap data past the needed LSN range. Bug fixed #1625466.
  • Percona Server cmake compiler would always attempt to build RocksDB even if -DWITHOUT_ROCKSDB=1 argument was specified. Bug fixed #1638455.
  • Lack of free pages in the buffer pool is not diagnosed with innodb_empty_free_list_algorithm set to backoff (which is the default). Bug fixed #1657026.
  • mysqld_safe now limits the use of rm and chown to avoid privilege escalation. chown can now be used only for /var/log directory. Bug fixed #1660265. Thanks to Dawid Golunski (https://legalhackers.com).
  • Renaming a TokuDB table to a non-existent database with tokudb_dir_per_db enabled would lead to a server crash. Bug fixed #1030.
  • Read Free Replication optimization could not be used for TokuDB partition tables. Bug fixed #1012.

Other bugs fixed: #1486747, #1617715, #1633988, #1638198 (upstream #82823), #1642230, #1646384, #1640810, #1647530, #1651121, #1658843, #1156772, #1644583, #1648389, #1648737, #1650256, and #1647723.

The release notes for Percona Server for MySQL 5.7.17-11 are available in the online documentation. Please report any bugs on the launchpad bug tracker.

Percona Live Featured Tutorial with Derek Downey, David Turner and René Cannaò — ProxySQL Tutorial

February 3, 2017 - 9:22am

Welcome to another post in the series of Percona Live featured tutorial speakers blogs! In these blogs, we’ll highlight some of the tutorial speakers that will be at this year’s Percona Live conference. We’ll also discuss how these tutorials can help you improve your database environment. Make sure to read to the end to get a special Percona Live 2017 registration bonus!

In this Percona Live featured tutorial, we’ll meet Derek Downey (OSDB Practice Advocate, Pythian), David Turner (Storage SRE, Uber) and René Cannaò (MySQL SRE, Dropbox / ProxySQL). Their session is ProxySQL Tutorial. There is a stigma attached to database proxies when it comes to MySQL. This tutorial hopes to blow away that stigma by showing you what can be done with a proxy designed from the ground up to perform. I had a chance to speak with Derek, David and René and learn a bit more about ProxySQL:

Percona: How did you get into database technology? What do you love about it?

Derek Downey

Derek: I took a relational database course in college based on Oracle. Set theory and the relational model made a lot of sense to me. After a few years as a web developer at a small company, I transitioned to a hybrid SysAdmin/DBA role and got my first taste of the potential of “the cloud” (and some of the drawbacks).

I really came to understand that data is the lifeblood of any organization, and making sure it is always available through any disaster – from human error to hurricanes – is a unique and exciting challenge.

You should never notice the DBA if they’re doing their job right. There’s not much praise for a DBA on a job well done. But it’s a vital position to keep a company running. And that suits me just fine.

David: I started working for the Advanced Projects Group at the University of Missouri, now known as MOREnet. They were largely responsible for connecting all of the libraries and schools in the state to the Internet. I was initially helping them with their Internet presence as a webmaster. Later they needed help with their databases. I got very excited about working with Oracle at the time, and decided to join that team.

My relationship with MySQL started primarily because the cost of sharding Oracle was so high. Additionally, MySQL’s replication allowed us to use slaves. Oracle’s Dataguard/standby options wouldn’t allow reads from the slaves at that time. Lastly, MySQL was sort of “wild west” fun, since it lacked so many other features that Oracle had long ago. You had to get creative. It has been humbling to see how much innovation has come from the community and how far MySQL has come. And this is only the beginning!

René Cannaò

René: My career followed the classic path of a system administrator that ends up becoming a DBA. I used to work for a few companies as webmaster,  and finally as SysAdmin for a web hosting company. I always saw a similar pattern: “the bottleneck is in the database.” Nobody ever knew why the database was the bottleneck. I volunteered to improve the performance of this “unknown system.” Learning was a fun experience, and the result was extremely rewarding. I love understanding how databases operate and their internals. This is the only way to be able to get the maximum performance: “scientia potentia est”!

Percona: Your tutorial is called “ProxySQL Tutorial.” What exactly is ProxySQL, and what does it do?

Derek: I’ll leave it to René, the creator of ProxySQL, to give more detail on exactly what it is. But for a DBA trying to ensure their data is always available, it is a new and exciting tool in our toolbox.

René: ProxySQL is the MySQL data gateway. It’s the Stargate that can inspect, control, transform, manage, and route all traffic between clients and database servers. It builds reliable and fault-tolerant networks. It is a software bridge that empowers MySQL DBAs, built by DBAs for DBAs, allowing them to control all MySQL traffic where previously such traffic could not be controlled either on the client side (normally the developers’ realm) or server side (where there are not enough tools).

David Turner

David: Architecturally, ProxySQL is a separate process between the client and the database. Because traffic passes through it, ProxySQL can become many things (three of which got my attention). It can be a multiplexer, a filter, and a replicator.

Multiplexers reduce many signals down to a few. Web servers often open many static connections to MySQL. Since MySQL can only support a limited number of connections before performance suffers, ProxySQL’s ability to transparently manage tens of thousands of connections while only opening a few to the database is a great feature.

Administrators can update ProxySQL to filter and even rewrite queries based on patterns they decide on. As someone that has worked in operations and seen how long it can take to disable misbehaving applications, this is a very compelling feature. With ProxySQL in place, I can completely block a query from the database in no time.

ProxySQL’s replication or mirroring capability means that all of the queries sent to one database can now be sent to N databases. As someone that has to roll out new versions of MySQL, test index changes, and benchmark hardware this is also a compelling feature.

Percona: What are the advantages of using ProxySQL in a database environment?

René: ProxySQL is the bridge between the clients and the servers. It creates two layers, and controls all the communication between the two. Sitting in the middle, ProxySQL provides a lot of advantages normally impossible to achieve in a standard database environment, such as throttling or blocking queries, rewriting queries, implementing sharding, read/write splitting, caching, duplicating traffic, handling backend failures, failovers, integration with HA solutions, generating real-time statistics, etc. All this, without any application change, and completely transparent to the application.

Derek: For me, ProxySQL decouples the application from the data layer. This provides more control over the backend database environment to the DBA in regards to queries, maintenance and failovers, without impact to the application.

David: In addition to the roles noted above, ProxySQL can be part of a failover solution, routing queries to a new master when the current master fails. Other advantages are splitting queries over multiple databases to distribute the load, provide additional metrics, etc.

Percona: What do you want attendees to take away from your tutorial session? Why should they attend?

Derek: This tutorial highlights what ProxySQL is trying to achieve, and discusses how to add ProxySQL to common architectures environments. Attendees will get hands-on experience with the technology, and learn how to install and configure ProxySQL to achieve query rewriting, seamless failover, and query mirroring.

David: Not only hands-on experience with ProxySQL, but an understanding of how much they can leverage with it. The more I use ProxySQL, the more advantages I see to it. For example, I did not realize that by clustering ProxySQL processes I can distribute the query matching and rewrites over many hosts, as well as use them as a caching layer.

René: ProxySQL is built upon very innovative technologies. Certain architectural concepts like hostgroups, chaining of query rules, granular routing and sharding, query retries and the very powerful Admin interface are concepts not always intuitive for DBAs with experience using other proxies. This tutorial helps understand these concepts, and attendees get hand-on experience in the configuration of ProxySQL in various scenarios.

Percona: What are you most looking forward to at Percona Live?

David: First, the people. Next, everything everyone is working on. We’re really lucky to work in such an innovative and collaborative industry. As databases evolve, we are on the ground floor of their evolution. What an exciting place to be.

Derek: I am mostly looking forward to reconnecting with my peers in the MySQL community. Both ones I’ve formerly worked with or previously met at Percona Live, as well as meeting new open source database professionals and hearing how they are providing solutions for their companies.

René: I am looking forward to attending sessions regarding new features in MySQL 8 and other new technologies. But moreover, I am excited to interact with MySQL users and get more input on how to improve ProxySQL so that it can become an indispensable tool in any MySQL environment.

Register for Percona Live Data Performance Conference 2017, and see Derek, David and René present their ProxySQL Tutorial. Use the code FeaturedTutorial and receive $30 off the current registration price!

Percona Live Data Performance Conference 2017 is the premier open source event for the data performance ecosystem. It is the place to be for the open source community as well as businesses that thrive in the MySQL, NoSQL, cloud, big data and Internet of Things (IoT) marketplaces. Attendees include DBAs, sysadmins, developers, architects, CTOs, CEOs, and vendors from around the world.

The Percona Live Data Performance Conference will be April 24-27, 2017 at the Hyatt Regency Santa Clara & The Santa Clara Convention Center.

PMM Alerting with Grafana: Working with Templated Dashboards

February 2, 2017 - 3:54pm

In this blog post, we will look into more intricate details of PMM alerting. More specifically, we’ll look at how to set up alerting based on templated dashboards.

Percona Monitoring and Management (PMM) 1.0.7 includes Grafana 4.0, which comes with the Alerting feature. Barrett Chambers shared how to enable alerting in general. This blog post looks at the specifics of setting up alerting based on the templated dashboards. Grafana 4.0 does not support basic alerting out-of-the-box.

This means if I try to set up an alert on the number of MySQL threads running, I get the error “Template variables are not supported in alert queries.”

What is the solution?

Until Grafana provides a better option, you need to do alerting based on graphs (which don’t use templating). This is how to do it.

Click on “Create New” in the Dashboards list to create a basic dashboard for your alerts:

Click on “Add Panel” and select “Graph”:

Click on the panel title of the related panel on the menu sign, and then click on “Panel JSON”.

This shows you the JSON of the panel, which will look like something like this:

Now you need to go back to the other browser window, and the dashboard with the graph you want to alert on. Show the JSON panel for it. In our case, we go to “MySQL Overview” and show the JSON for “MySQL Active Threads” panel.

Copy the JSON from the “MySQL Active Threads” panel and paste it into the new panel in the dashboard created for alerting.

Once we have done the copy/paste, click on the green Update button, and we’ll see the broken panel:

It’s broken because we’re using templating variables in dashboard expressions. None of them are set up in this dashboard. Expressions won’t work. We must replace the template variables in the formulas with actual hosts, instances, mount points, etc., for we want to alert on:

We need to change $host to the name of the host we want to alert on, and the $interval should align with the data capture interval (here we’ll set it to 5 seconds):

If correctly set up, you should see the graph showing the data.

Finally, we can go to edit the graph. Click on the “Alert” and “Create Alert”.

Specify Evaluate Every to create an alert. This sets up the evaluation interval for the alert rule. Obviously, the more often the alert evaluates the condition, the more quickly you get alerted if something goes wrong (as well as alert conditions).

In our case, we want to get an alert if the number of running threads are sustained at a high rate. To do this, look at the minimum number of threads for last minute to be above 30:

Note that our query has two parameters: “A” is the number of threads connected, and “B” is the number of threads running. We’re choosing to Alert on “B”. 

The beautiful thing Grafana does is show the alert threshold clearly on the graph, and allows you to edit the alert just by moving this alert line with a mouse:

You may want to click on the floppy drive at the top to save dashboard (giving it whatever identifying name you want).

At this point, you should see the alert working. A little heart sign appears by the graph title, colored green (indicating it is not active) or red (indicating it is active). Additionally, you will see the red and green vertical lines in the alert history. These show when this alert gets triggered and when the system went back to normal.

You probably want to set up notifications as well as see alerts on the graphs. 

To set up notifications, go to the Grafana Configuration menu and configure Alerting. There are Grafana Support Email, Slack, Pagerduty and general Webhook notification options (with more on the way, I’m sure).

The same way you added the “Graph” panel to set up an alert, you can add the “Alert List” panel to see all the alerts you have set up (and their status):

Summary

As you can see, it is possible to set up alerts in PMM using the new Grafana 4.0 alerting feature. It is not very convenient or easy to do. This is first alerting support release for Grafana and PMM. As such, I’m sure it will become much easier and more convenient over time.

Vote Percona in LinuxQuestions.org Members Choice Awards 2016

February 2, 2017 - 12:40pm

Percona is calling on you! Vote for Percona for Database of the Year in LinuxQuestions.org Members Choice Awards 2016. Help Percona get recognized as one of the best database options for data performance. Percona provides free, fully compatible, enhanced, open source drop-in replacement database software with superior performance, scalability and instrumentation.

LinuxQuestions.org, or LQ for short, is a community-driven, self-help website for Linux users. Each year, LinuxQuestions.org holds an annual competition to recognize the year’s best-in-breed technologies. The online Linux community determines the winners of each category!

You can vote now for your favorite database of 2016 (Percona, of course!). This is your chance to be heard!

Voting ends on February 7, 2017. You must be a registered member of LinuxQuestions.org with at least one post on their forums to vote.

Percona Server for MySQL 5.5.54-38.6 is now available

February 1, 2017 - 12:46pm

Percona announces the release of Percona Server for MySQL 5.5.54-38.6 on February 1, 2017. Based on MySQL 5.5.54, including all the bug fixes in it, Percona Server for MySQL 5.5.54-38.6 is now the current stable release in the 5.5 series.

Percona Server for MySQL is open-source and free. You can find release details in the 5.5.54-38.6 milestone on Launchpad. Downloads are available here and from the Percona Software Repositories.

Bugs Fixed:
  • Fixed new compilation warnings with GCC 6. Bugs fixed #1641612 and #1644183.
  • CONCURRENT_CONNECTIONS column in the USER_STATISTICS table was showing incorrect values. Bug fixed #728082.
  • Audit Log Plugin when set to JSON format was not escaping characters properly. Bug fixed #1548745.
  • mysqld_safe now limits the use of rm and chown to avoid privilege escalation. chown can now be used only for /var/log directory. Bug fixed #1660265.

Other bugs fixed: #1638897, #1644174, #1644547, and #1644558.

Find the release notes for Percona Server for MySQL 5.5.54-38.6 in our online documentation. Report bugs on the launchpad bug tracker.

Docker Security Vulnerability CVE-2016-9962

January 31, 2017 - 9:39am

Docker 1.12.6 was released to address CVE-2016-9962. CVE-2016-9962 is a serious vulnerability with RunC.

Quoting the coreos page (linked above):

“RunC allowed additional container processes via runc exec to be ptraced by the pid 1 of the container. This allows the main processes of the container, if running as root, to gain access to file-descriptors of these new processes during the initialization and can lead to container escapes or modification of runC state before the process is fully placed inside the container.”

In short, IF processes run as root inside a container they could potentially break out of the container and gain access over the host.

My recommendation at this time is to apply the same basic security tenants for containers as you would (I hope) for VM and baremetal installs. In other words, ensure you are adhering to a Path of Least Privilege as a best practice and not running as root for conevience’s sake.

Prior to this, we made changes to PMM prior to version 1.0.4 to reduce the number of processes within the container that ran as root. As such, only the processes required to do so run as root. All other processes run as a lower privilege user.

Check here for documentation on PMM, and use the JIRA project to raise bugs (JIRA requires registration).

To comment on running a database within docker, I’ve reviewed the following images

  • percona-server image: I have verified it does not run as root, and runs as a mysql user (for 5.7.16 at least)
  • percona-server-mongodb: I have worked with our teams internally and can confirm that the latest image no longer runs as root (you will to run the latest image, however, to see this change via docker pull)

Please comment below with any questions.

MySQL Sharding Models for SaaS Applications

January 30, 2017 - 3:16pm

In this blog post, I’ll discuss MySQL sharding models, and how they apply to SaaS application environments.

MySQL is one of the most popular database technologies used to build many modern SaaS applications, ranging from simple productivity tools to business-critical applications for the financial and healthcare industries.

Pretty much any large scale SaaS application powered by MySQL uses sharding to scale. In this blog post, we will discuss sharding choices as they apply to these kinds of applications.

In MySQL, unlike in some more modern technologies such as MongoDB, there is no standard sharding implementation that the vast majority of applications use. In fact, if anything “no standard” is the standard. The common practice is to roll your own sharding framework, as famous MySQL deployments such as Facebook and Twitter have done. MySQL Cluster – the MySQL software that has built-in Automatic Sharding functionality – is rarely deployed (for a variety of reasons). MySQL Fabric, which has been the official sharding framework, has no traction either.

When sharding today, you have a choice of rolling your own system from scratch, using comprehensive sharding platform such as Vitess or using a proxy solution to assist you with sharding. For proxy solutions, MySQL Router is the official solution. But in reality, third party solutions such as open source ProxySQL, commercial ScaleArc and semi-commercial (BSL)  MariaDB MaxScale are widely used. Keep in mind, however, that traffic routing is only one of the problems that exist in large scale sharding implementations.

Beneath all these “front end” choices for sharding on the application database connection framework or database proxy, there are some lower level decisions that you’ve got to make. Namely, around how your data is going to be led out and organized on the MySQL nodes.

When it comes to SaaS applications, at least one answer is simple. It typically makes sense to shard your data by “customer” or “organization” using some sort of mapping tables. In the vast majority of cases, single node (or replicated cluster) should be powerful enough to handle all the data and load coming from each customer.

What Should I Ask Myself Now?

The next set questions you should ask yourself are around your SaaS applications:

  • How much revenue per customer are you generating?
  • Do your customers (or regulations) require data segregation?
  • Are all the customers about the same, or are there outliers?
  • Are all your customers running the same database schema?

I address the answers in the sections below.

How Much Revenue?

How much revenue per customer you’re generating is an important number. It defines how much infrastructure costs per customer you can afford. In the case of “freemium” models, and customers generating less than $1 a month an average, you might need to ensure low overhead per customer (even if you have to compromise on customer isolation).

How much revenue per customer you’re generating is an important number. It defines how much infrastructure costs per customer you can afford. In the case of “freemium” models, and customers generating less than $1 a month an average, you might need to ensure low overhead per customer (even if you have to compromise on customer isolation).

Typically with low revenue customers, you have to co-locate the data inside the same MySQL instance (potentially even same tables). In the case of high revenue customers, isolation in separate MySQL instances (or even containers or virtualized OS instances) might be possible.

Data Segregation?

Isolation is another important area of consideration. Some enterprise customers might require that their data is physically separate from others. There could also be government regulations in play that require customer data to be stored in a specific physical location. If this is the case, you’re looking at completely dedicated customer environments. Or at the very least, separate database instances (which come with additional costs).

Customer Types?

Customer size and requirements are also important. A system designed to handle all customers of approximately the same scale (for example, personal accounting) is going to be different than if you are in the business of blog hosting. Some blogs might be 10,000 times more popular than the average.

Same Database Schema?

Finally, there is a there is the big question of whether all your customers are running the same database schema and same software version. If you want to support different software versions (if your customers require a negotiated maintenance window for software upgrades, for example) or different database schemas (if the schema is dependent on the custom functionality and modules customers might use, for example), keeping such customers in different MySQL schemas make sense.

Sharding Models

This gets us to the following sharding isolation models, ranging from lowest to highest:

  • Customers Share Schemas. This is the best choice when you have very large numbers of low-revenue customers. In this case, you would map multiple customers to the same set of tables, and include something like a customer_id field in them to filter customer data. This approach minimizes customer overhead and reduces customer isolation. It’s harder to backup/restore data for individual customers, and it is easier to introduce coding mistakes that can access other customers data. This method does not mean there is only one schema, but that there is a one-to-many relationship between schemas and customers.  For example, you might have 100 schema’s per MySQL instance, each handling 1000 to 10000 customers (depending on the application). Note that with a well-designed sharding implementation, you should be able to map customers individually to schemas. This allows you to have key customer data stored in dedicated schemas, or even on dedicated nodes.
  • Schema per Customer. This is probably the most common sharding approach in MySQL powered SaaS applications. Especially ones that have substantial revenue ($10+ per month / per customer). In this model, each customer’s data is stored in its own schema (database). This makes it very easy to backup/restore individual customers. It allows customers to have different schemas (i.e., add custom tables). It also allows them to run different versions of the application if desired. This approach allows the application server to use different MySQL users connecting on behalf of different customers, which adds an extra level of protection from accidental (or intentional) access of data that belongs to different customers. The schema per customer approach also makes it easier to move the shards around, and limits maintenance impact. The downside of this approach is higher overhead. It also results in a large number of tables per instance, and potentially larger numbers of files (which can be hard to manage).
  • Database Instance per Customer. You achieve even better isolation by having a MySQL instance per customer. This approach, however, increases overhead even further. The recent rise of light virtualization technologies and containers has reduced its usage.
  • OS Instance/Container per Customer. This approach allows you to improve isolation even further. It can be used for any customer, but can also be applied to selected customers in a model that uses Schema per Customer model for a majority of them.  Dedicated OS Instance, with improved isolation and better performance SLAs, might be a feature of some premium customer tiers. This method not only allows better isolation, but it also let’s you handle outliers better. You might chose to run a majority of your customers on the hardware (or cloud instance) that has best price/performance numbers, and also place some of the larger customers on the highest performance nodes.
  • Environment per customer. Finally, if you take this all the way you can build completely separate environments for customers. This includes databases, application servers and other required components. This is especially useful if you need to deploy the application close to the customer – which includes the appliance model, or deployment in the customer’s data center or cloud provider. This also allows you to accommodate customers if their data must be stored in a specific location. This is often due to government regulations. It is worth noting that many SaaS applications, even if they do not quite have one environment per customer, have multiple independent environments. These are often hosted in different locations or availability zones. Such setups allow you to reduce the impact of large-scale failures to only a portion of your customers. This avoids overloading your customer service group and allowing the operational organization to focus on repairing smaller environments.

The farther you go down this route – from the shared schema to an environment per customer – the more important is to have a high level of automation. With a shared schema, you often can get by with little automation (and some environments manually set up) and all the schema’s pre-created. If customer sign up requires setting up dedicated database instance or the whole environment, manual implementation doesn’t scale. For this type of setup, you need state-of-the-art automation and orchestration.

Conclusion

I hope this helps you to understand your options for MySQL sharding models. Each of the different sharding models for SaaS applications powered by MySQL have benefits and drawbacks. As you can see, many of these approaches require you to work with a large number of tables in the MySQL – this will be the topic of one of my next posts!

MariaDB ColumnStore

January 30, 2017 - 9:29am

Last month, MariaDB officially released MariaDB ColumnStore, their column store engine for MySQL. This post discusses what it is (and isn’t), why it matters and how you can approach a test of it.

What is ColumnStore?

ColumnStore is a storage engine that turns traditional MySQL storage concepts on their head. Instead of storing the data by row, a column store stores the data by column (obviously). This provides advantages for certain types of data, and certain types of queries run against that data. See my previous post for more details on column-based storage systems.

ColumnStore is a fork of InfiniDB and carries forward many of the concepts behind that product. InfiniDB ceased operations in 2014. With the front end managed through MariaDB, you get access to all of the expected security and audit options of MariaDB. MariaDB designed ColumnStore as a massively parallel database, working best in an environment with multiple servers. This is somewhat different than a traditional row store database.

ColumnStore stores columnar data in a concept called an “extent.” An extent contains a range of values for a single column. Each extent contains no more than 8 million values. It stores additional values in a new extent. The extents for a single column get distributed across the database nodes, known as “Performance Modules” in ColumnStore. It stores each unique extent on more than one node, thus providing data redundancy and removing the need for replication. If a node is down, and it contains an extent needed for a query, that same extent is found on another node in the environment. This data redundancy also provides a high availability environment.

The query engine determines which extents process query requests. Since the data in an extent is often preordered (time series data, for example), many queries can ignore individual extents since they cannot contain any data needed for the query. If we are only looking for data from February 2017, for example, extents containing data outside of that range get ignored. However, if a query requires data from many or all extents on a single column, the query takes much longer to complete.

Unlike some traditional column store vendors, that take an all or nothing approach to storage, MariaDB decided to go with a mixed concept. In a MariaDB MySQL database, you can mix traditional InnoDB storage with the new ColumnStore storage, just like you used to mix InnoDB and MyISAM. This presents some nice options, not the least of which is that it provides a way to “dip your toe” into the world of column stores. On the other hand, it could lead to people using the ColumnStore engine in non-optimal ways. Also, the differences in what is considered optimal architecture between these two storage options make it hard to see how this plays out in the real world.

Data Definition

As discussed in the earlier post, column storage works great for specific types of data and queries. It is important that your data definitions are as tight as possible, and that your queries are appropriate for column-based data.

Many people set their field definition as VARCHAR(256) when setting up a new database. They might not know what type of data gets stored in the new field. This broad definition allows you to store whatever you throw at the database. The negative effect for row store is that it can cause over-allocation of storage – but it only has a minimal effect on queries.

In a column store, the field definition can drive decisions about the compression methods for storing the data, along with sorting implications. Columnar data can use storage more efficiently than a row store, since the data for a single column is well-defined. This leads to selecting the best compression algorithm for the data. If that data is poorly defined, the selected compression algorithm might not be the best for the data.

Sorting is also a problem in a column store when the data types are not well-defined. We’ve all seen integer or date data that is sorted alphabetically. While it can be annoying, we can still adjust to that sorting method to find what we need. Since a column store is often used to perform analytical queries over a range of data, this poorly-sorted data can present a bigger problem. If you specify a column to be VARCHAR and only include date information, that data is sorted alphabetically. The same column defined as DATE causes the data to be sorted by date. This chart shows the difference (date format is mm/dd/yy)

Alphabetic Sort Date Sort 01/01/17 01/01/17 01/11/17 01/02/17 01/02/17 01/04/17 01/21/17 01/11/17 01/4/17 01/21/17 11/01/17 02/01/17 11/02/17 11/01/17 02/01/17 11/02/17

 

Imagine running a query over a range of dates (requesting all activity in the months of January and February 2017, for example). In the alphabetic sort, this requires working through the whole file, since the data for November shows up between the data for January and February. In the date sort, the query only reads the until the end of February. We know there can be no more matching data after that. The alphabetic sort leads to more I/O, more query time and less happiness on the part of the user.

Why Should You Care About ColumnStore?

The first reason is that it allows you to try out column storage without doing a massive shift in technology and with minimal effort. By setting up some tables in a MariaDB database to use the ColumnStore engine, you can benefit from the storage efficiencies and faster query capabilities, provided that the data you’ve selected for this purpose is sound. This means that the data definitions should be tight (always a good plan anyway), and the queries should be more analytical than transactional. For a purely transactional workflow, a row store is the logical choice. For a purely analytical workflow, a column store is the logical choice. ColumnStore allows you to easily mix the two storage options so that you can have the best match possible. It is still important to know what type of workflow you’re dealing with, and match the storage engine to that need.

Another solid reason is that it is a great fit if you are already doing analysis over massive amounts of data. Any column store shines when asked to look at relatively few columns of data (ideally the column or two that are being aggregated and other columns to locate and group the data). If you are already running these types of queries in MySQL, ColumnStore would likely be a good fit.

But There Be Dragons!

As with any new technology, ColumnStore might not be a good fit for everyone. Given that you can mix and match your storage engines, with ColumnStore for some tables and InnoDB for others, it can be tempting to just go ahead with a ColumnStore test doing things the same way you always did in the past. While this still yields results, those results might not be a true test of the technology. It’s like trying to drive your minivan the same way you used to drive your sports car. “Hey, my Alfa Romeo never flipped over taking these turns at high speed!”

To effectively use ColumnStore, it’s important to match it to a proper analytical workload. This means that you will likely do more bulk loading into these tables, since there is additional overhead in writing the data out into the column files. The overall workflow should be more read-intensive. The queries should only look for data from a small set of fields, but can span massive amounts of data within a single column. In my earlier post, there’s also a discussion about normalization of data and how denormalizing data is more common in columnar databases.

You should address these issues in your testing for a valid conclusion.

The minimum specifications for ColumnStore also point to a need for a more advanced infrastructure than is often seen for transactional data. This is to support batch loading, read intensive workloads and possibly different ETL processes for each type of data. In fact, MariaDB states in the installation documentation for ColumnStore that it must be completed as a new installation of MariaDB. You must remove any existing installations of MariaDB or MySQL before installing the ColumnStore-enabled RPM on a system.

Is It Right for Me?

ColumnStore might fit well into your organization. But like haggis, it’s not for everyone. If you need analytical queries, it is a great option. If your workload is more read-intensive, it could still work for you. As we move to a more Internet of Things (IoT) world, we’re likely to see a need for more of this type of query work. In order to accurately present each user with the best possible Internet experience, we might want to analyze their activities over spans of time and come up with the best match for future needs.

Seriously consider if making the move to ColumnStore is right for you. It is newer software (version 1.0.6, the first GA version, was released on December 14, 2016, and 1.0.7 was released on January 23, 2017), so it might go through changes as it matures. Though a new product, it is based on InfiniDB concepts (which are somewhat dated). MariaDB has lots of plans for additional integrations and support for ancillary products that are absent in the current release.

MariaDB took a huge step forward with ColumnStore. But do yourself a favor and consider whether it is right for you before testing it out. Also, make sure that you are not trying to force your current workflow into the column store box. Kids know that we cannot put a square peg in a round hole, but we adults often try to do just that. Finding the right peg saves you lots of time, hassle and annoyance.

Percona Software News and Roadmap Update with CEO Peter Zaitsev: Q1 2017

January 27, 2017 - 2:06pm

This blog post is a summary of the webinar Percona Software News and Roadmap Update – Q1 2017 given by Peter Zaitsev on January 12, 2017.

Over the last few months, I’ve had the opportunity to meet and talk with many of Percona’s customers. I love these meetings, and I always get a bunch of questions about what we’re doing, what our plans are and what releases are coming.

I’m pleased to say there is a great deal going on at Percona, and I thought giving a quick talk about our current software and services, along with our plans, would provide a simple reference for many of these questions.

A full recording of this webinar, along with the presentation slide deck, can be found here.

Percona Solutions and Services

Let me start by laying out Percona’s company purpose:

To champion unbiased open source database solutions.

What does this mean? It means that we write software to offer you better solutions, and we use the best of what software and technology exist in the open source community.

Percona stands by a set of principles that we feel define us as a company, and are a promise to our customers:

  • 100% free and open source software
  • Focused on finding solution to maximize your success
  • Open source database strategy consulting and implementation
  • No vendor lock-in required

We offer trusted and unbiased expert solutions, support and resource in a broad software ecosystem, including:

We also have specialization options for PaaS, IaaS, and SaaS solutions like Amazon Web Services, OpenStack, Google Cloud Platform, OpenShift, Ceph, Docker and Kubernetes.

Percona’s immediate business focus includes building long-term partnership relationships through support and managed services.

The next few sections detail our current service offerings, with some outlook on our plans.

98% Customer Satisfaction Rating

Over the last six months, Percona has consistently maintained a 98% Customer Satisfaction Rating!

Customer Success Team

Our expanded Customer Success Team is here to ensure you’re getting most out of your Percona Services Subscription.

Managed Services Best Practices

  • Unification based on best practices
  • Organization changes to offer more personal service
  • Increased automation

Ongoing Services

Consulting and Training. Our consulting and training services are available to assist you with whatever project or staff needs you have.

  • Onsite and remote
  • 4 hours to full time (weeks or months)
  • Project and staff augmentation

Advanced HA Included with Enterprise and Premier Support. Starting this past Spring, we included advance high availability (HA) support as part of our Enterprise and Premier support tiers. This advanced support includes coverage for:

  • Percona XtraDB Cluster
  • MariaDB Galera Cluster
  • Galera Cluster for MySQL
  • Upcoming MySQL group replication
  • Upcoming MySQL Innodb Cluster

Enterprise Wide Support Agreements. Our new Enterprise Wide Support option allows you to buy per-environment support coverage that covers all of the servers in your environment, rather than on a per-server basis. This method of support can save you money, because it:

  • Covers both “MySQL” and “MongoDB”
  • Means you don’t have to count servers
  • Provides highly customized coverage

 

Simplified Support Pricing. Get easy to understand support pricing quickly.

To discuss how Percona Support can help your business, please call us at +1-888-316-9775 (USA),
+44 203 608 6727 (Europe), or have us contact you.

New Percona Online Store – Easy to Buy, Pay Monthly

Percona Software

Below are the latest and upcoming features in Percona’s software. All of Percona’s software adheres to the following principles:

  • 100% free and open source
  • No restricted “Enterprise” version
  • No “open core”
  • No BS-licensing (BSL)
Percona Server for MySQL 5.7

Overview

  • 100% Compatible with MySQL 5.7 Community Edition
  • 100% Free and Open Source
  • Includes Alternatives to Many MySQL Enterprise Features
  • Includes TokuDB Storage Engine
  • Focus on Performance and Operational Visibility

Latest Improvements

Features about to be Released 

  • Integration of TokuDB and Performance Schema
  • MyRocks integration in Percona Server
  • MySQL Group Replication
  • Starting to look towards MySQL 8
Percona XtraBackup 2.4

Overview

  • #1 open source binary hot backup solution for MySQL
  • Alternative to MySQL Enterprise backup
  • Parallel backups, incremental backups, streaming, encryption
  • Supports MySQL, MariaDB, Percona Server

New Features

  • Support SHA256 passwords and secure connection to server
  • Improved Security (CVE-2016-6225)
  • Wrong passphrase detection
Percona Toolkit

Overview

  • “Swiss Army Knife” of tools
  • Helps DBAs be more efficient
  • Helps DBAs make fewer mistakes
  • Supports MySQL, MariaDB, Percona Server, Amazon RDS MySQL

New Features

  • Improved fingerprinting in pt-query-digest
  • Pause file for pt-online-schema-change
  • Provide information about transparent huge pages

Coming Soon

  • Working towards Percona Toolkit 3.0 release
  • Comprehensive support for MongoDB
  • New tools are now implemented in Go
Percona Server for MongoDB 3.2

Overview

  • 100% compatible with MongoDB 3.2 Community Edition
  • 100% open source
  • Alternatives for many MongoDB Enterprise features
  • MongoRocks (RocksDB) storage engine
  • Percona Memory Engine

New

  • Percona Server for MongoDB 3.2 – GA
  • Support for MongoRocks storage engine
  • PerconaFT storage engine depreciated
  • Implemented Percona Memory Engine

Coming Soon

  • Percona Server for MongoDB 3.4
  • Fully compatible with MongoDB 3.4 Community Edition
  • Updated RocksDB storage engine
  • Universal hot backup for WiredTiger and MongoRocks
  • Profiling rate limiting (query sampling)
Percona Memory Engine for MongoDB

Benchmarks

Percona Memory Engine for MongoDB® is a 100 percent open source in-memory storage engine for Percona Server for MongoDB.

Based on the in-memory storage engine used in MongoDB Enterprise Edition, WiredTiger, Percona Memory Engine for MongoDB delivers extremely high performance and reduced costs for a variety of use cases, including application cache, sophisticated data manipulation, session management and more.

Below are some benchmarks that we ran to demonstrate Percona Memory Engine’s performance.

Percona XtraDB Cluster 5.7

Overview

  • Based on Percona Server 5.7
  • Easiest way to bring HA in your MySQL environment
  • Designed to work well in the cloud
  • Multi-master replication with no conflicts
  • Automatic node provisioning for auto-scaling and self-healing

Goals

  • Brought PXC development in-house to server our customers better
  • Provide complete clustering solution, not set of LEGO pieces
  • Improve usability and ease of use
  • Focus on quality

Highlights

  • Integrated cluster-aware load balancer with ProxySQL
  • Instrumentation with Performance Schema
  • Support for data at rest encryption (InnoDB tablespace encryption)
  • Your data is safe by default with “strict mode” – prevents using features that do not work correctly
  • Integration with Percona Monitoring and Management (PMM)

New in Percona XtraDB Cluster 5.7

  • One option to secure all network communication: pxc-encrypt-cluster-traffic
  • Zero downtime maintenance with ProxySQL and Maintenance Mode
Percona Monitoring and Management

Overview

  • Comprehensive database-focused monitoring
  • 100% open source, roll-your-own solution
  • Easy to install and use
  • Supports MySQL and MongoDB
  • Version 1.0 focuses on trending and query analyses
  • Management features to come

Examples of PMM Screens

What queries are causing the load?

Why are they causing this load?

How to fix them:

System information:

What happens on OS and hardware level:

As well as the database level:

New in Percona Monitoring and Management

  • Continuing to improve and expand dashboards with every release
  • Includes Grafana 4.0 (with basic Alerting)
  • SSL support for server-agent communications
  • Supports authentication for server-agent communication
  • Added support for Amazon RDS
  • Reduced space consumption by using advanced compression

Coming Soon 

  • PMM server available as AMI and Virtual Appliance image
  • Better MongoDB dashboards
  • Continuing work on dashboards Improvement
  • Query analytics application refinements
  • Short term continuing focus on monitoring functionality

Check out the Demo

Percona Live Open Source Database Conference 2017 is right around the corner!

The Percona Live Open Source Database Conference is the premier event for the diverse and active open source database community, as well as businesses that develop and use open source database software. The conferences have a technical focus with an emphasis on the core topics of MySQL, MongoDB, PostgreSQL and other open source databases. Tackling subjects such as analytics, architecture and design, security, operations, scalability and performance, Percona Live provides in-depth discussions for your high-availability, IoT, cloud, big data and other changing business needs. This conference is an opportunity to network with peers and technology professionals by bringing together accomplished DBA’s, system architects and developers from around the world to share their knowledge and experience – all to help you learn how to tackle your open source database challenges in a whole new way

This conference has something for everyone!

Register now and get the early bird rate, but hurry prices go up Jan 31st.

Sponsorship opportunities are available as well. Become a Percona Live Sponsor, download the prospectus here.

 

When MySQL Lies: Wrong seconds_behind_master with slave_parallel_workers > 0

January 27, 2017 - 11:03am

In today’s blog, I will show an issue with seconds_behind_master that one of our clients faced when running slave_parallel_works > 0. We found out that the reported seconds_behind_master from SHOW SLAVE STATUS was lying. To be more specific, I’m talking about bugs #84415 and #1654091.

The Issue

MySQL will not report the correct slave lag if you have slave_parallel_workers> 0. Let’s show it in practice.

I’ll use MySQL Sandbox to speed up one master and two slaves on MySQL version 5.7.17, and sysbench to populate the database:

# Create sandboxes make_replication_sandbox /path/to/mysql/5.7.17 # Create table with 1.5M rows on it sysbench --test=/usr/share/sysbench/tests/db/oltp.lua --mysql-host=localhost --mysql-user=msandbox --mysql-password=msandbox --mysql-socket=/tmp/mysql_sandbox20192.sock --mysql-db=test --oltp-table-size=1500000 prepare # Add slave_parallel_workers=5 and slave_pending_jobs_size_max=1G" on node1 echo "slave_parallel_workers=5" >> node1/my.sandbox.cnf echo "slave_pending_jobs_size_max=1G" >> node1/my.sandbox.cnf node1/restart

Monitor Replication lag via SHOW SLAVE STATUS:

for i in {1..1000}; do ( node1/use -e "SHOW SLAVE STATUSG" | grep "Seconds_Behind_Master" | awk '{print "Node1: " $2}' & sleep 0.1 ; node2/use -e "SHOW SLAVE STATUSG" | grep "Seconds_Behind_Master" | awk '{print "Node2: " $2}' & ); sleep 1; done

On a separate terminal, DELETE some rows in the test.sbtest1 table on the master, and monitor the above output once the master completes the delete command:

DELETE FROM test.sbtest1 WHERE id > 100;

Here is a sample output:

master [localhost] {msandbox} (test) > DELETE FROM test.sbtest1 WHERE id > 100; Query OK, 1499900 rows affected (46.42 sec) . . . Node1: 0 Node2: 0 Node1: 0 Node2: 48 Node1: 0 Node2: 48 Node1: 0 Node2: 49 Node1: 0 Node2: 50 . . . Node1: 0 Node2: 90 Node1: 0 Node2: 91 Node1: 0 Node2: 0 Node1: 0 Node2: 0

As you can see, node1 (which is running with slave_parallel_workers = 5) doesn’t report any lag.

The Workaround

We can workaround this issue by querying performance_schema.threads:

SELECT PROCESSLIST_TIME FROM performance_schema.threads WHERE NAME = 'thread/sql/slave_worker' AND (PROCESSLIST_STATE IS NULL or PROCESSLIST_STATE != 'Waiting for an event from Coordinator') ORDER BY PROCESSLIST_TIME DESC LIMIT 1;

Let’s modify our monitoring script, and use the above query to monitor the lag on node1:

for i in {1..1000}; do ( node1/use -BNe "SELECT PROCESSLIST_TIME FROM performance_schema.threads WHERE NAME = 'thread/sql/slave_worker' AND (PROCESSLIST_STATE IS NULL or PROCESSLIST_STATE != 'Waiting for an event from Coordinator') ORDER BY PROCESSLIST_TIME DESC LIMIT 1 INTO @delay; SELECT IFNULL(@delay, 0) AS 'lag';" | awk '{print "Node1: " $1}' & sleep 0.1 ; node2/use -e "SHOW SLAVE STATUSG" | grep "Seconds_Behind_Master" | awk '{print "Node2: " $2}' & ); sleep 1; done

master [localhost] {msandbox} (test) > DELETE FROM test.sbtest1 WHERE id > 100; Query OK, 1499900 rows affected (45.21 sec) Node1: 0 Node2: 0 Node1: 0 Node2: 0 Node1: 45 Node2: 45 Node1: 46 Node2: 46 . . . Node1: 77 Node2: 77 Node1: 78 Node2: 79 Node1: 0 Node2: 80 Node1: 0 Node2: 81 Node1: 0 Node2: 0 Node1: 0 Node2: 0

Please note that in our query to performance_schema.threads, we are filtering PROCESSLIST_STATE “NULL” and “!= Waiting for an event from Coordinator”. The correct state is “Executing Event”, but it seems like it doesn’t correctly report that state (#84655).

Summary

MySQL parallel replication is a nice feature, but we still need to make sure we are aware of any potential issues it might bring. Most monitoring systems use the output of SHOW SLAVE STATUS to verify whether or not the slave is lagging behind the master. As shown above, it has its caveats.

As always, we should test, test and test again before implementing any change like this in production!

Percona Live Featured Tutorial with Frédéric Descamps — MySQL InnoDB Cluster & Group Replication in a Nutshell: Hands-On Tutorial

January 26, 2017 - 3:58pm

Welcome to another post in the series of Percona Live featured tutorial speakers blogs! In these blogs, we’ll highlight some of the tutorial speakers that will be at this year’s Percona Live conference. We’ll also discuss how these tutorials can help you improve your database environment. Make sure to read to the end to get a special Percona Live 2017 registration bonus!

In this Percona Live featured tutorial, we’ll meet Frédéric Descamps, MySQL Community Manager at Oracle. Frédéric is probably better known in the community as “LeFred” (Twitter: @lefred)! His tutorial is MySQL InnoDB Cluster and Group Replication in a Nutshell: Hands-On Tutorial (along with  Part 2). Frédéric is delivering this talk with Percona’s MySQL Practice Manager Kenny Gryp. Attendees will get their hands on virtual machines and migrate standard Master/Slave architecture to the new MySQL InnoDB Cluster (native Group Replication) with minimal downtime. I had a chance to speak with Frédéric and learn a bit more about InnoDB Cluster and Group Replication:

Percona: How did you get into database technology? What do you love about it?

Frédéric: I started with SQL on VMS and DBASE during my IT courses. I wrote my thesis on SQLServer replication. To be honest, the implementation at the time wasn’t particularly good. At the same time, I enjoyed hacking a Perl module that allowed you to run SQL queries against plain text files. Then I worked as a Progress developer for MFG/Pro (a big customized ERP). When I decided to work exclusively for an open source company, I was managing more and more customers’ databases in MySQL (3.23 and 4.x), so my colleagues and I took MySQL training. It was still MySQL AB at that time. I passed my MySQL 4.1 Core and Professional Certification, and I ended up delivering MySQL Training for MySQL AB too. Some might also remember that I worked for a company called Percona for a while, before moving on to Oracle!

Percona: Your and Kenny’s tutorial is called “MySQL InnoDB Cluster & Group Replication in a nutshell: hands-on tutorial.” Why would somebody want to migrate to this technology?

Frédéric: The main reason to migrate to MySQL InnoDB is to achieve high availability (HA) easily for your MySQL database, while still maintaining performance.

Thanks to  MySQLShell’s adminAPI, you can create a cluster in less than five minutes. All the management can be done remotely, with just some shell commands. Additionally, for Group Replication our engineers have leveraged existing standard MySQL infrastructures (GTIDs, Multi-Source Replication, Multi-threaded Slave Applier, Binary Logs, etc.), which are already well known by the majority of MySQL DBAs.

Percona: How can moving to a high availability environment help businesses?

Frédéric: Time is money! Many businesses can’t afford downtime anymore. Having a reliable HA solution is crucial for businesses on the Internet. Expectations have changed: users want this to be natively supported inside the database technology versus externally. For example, when I started to work in IT, it was very common to have several maintenance windows during the night. But currently, and almost universally, the customer base is spread worldwide. Any time is during business hours somewhere in the world!

Percona: What do you want attendees to take away from your tutorial session? Why should they attend?

Frédéric: I think that current HA solutions are too complex to setup and manage. They use external tools. In our tutorial, Kenny and I will demonstrate how MySQL InnoDB Cluster, being an internal implementation, is extremely easy to use. We will also cover some scenarios where things go wrong, and how to deal with them. Performance and ease-of-use were two key considerations in the design of InnoDB Cluster.

Percona: What are you most looking forward to at Percona Live?

Frédéric: Like every time I’ve attended, my main goal is to bring to the audience all the new and amazing stuff we are implementing in MySQL. MySQL has evolved quickly these last few years, and we don’t really plan to slow down. I also really enjoy the feedback from users and other MySQL professionals. This helps focus us on what really matters for our users. And finally, it’s a great opportunity to re-connect with ex-colleagues and friends.

You can find out more about Frédéric Descamps and his work with InnoDB Cluster at his Twitter handle @lefredRegister for Percona Live Data Performance Conference 2017, and see Frédéric and Kenny present their MySQL InnoDB Cluster and Group Replication in a Nutshell: Hands-On Tutorial talk. Use the code FeaturedTalk and receive $30 off the current registration price!

Percona Live Data Performance Conference 2017 is the premier open source event for the data performance ecosystem. It is the place to be for the open source community as well as businesses that thrive in the MySQL, NoSQL, cloud, big data and Internet of Things (IoT) marketplaces. Attendees include DBAs, sysadmins, developers, architects, CTOs, CEOs, and vendors from around the world.

The Percona Live Data Performance Conference will be April 24-27, 2017 at the Hyatt Regency Santa Clara & The Santa Clara Convention Center.

Performance Schema Benchmarks: OLTP RW

January 26, 2017 - 11:19am

In this blog post, we’ll look at Performance Schema benchmarks for OLTP Read/Write workloads.

I am in love with Performance Schema and talk a lot about it. Performance Schema is a revolutionary MySQL troubleshooting instrument, but earlier versions had performance issues. Many of these issues are fixed now, and the default options work quickly and reliably. However, there is no free lunch! It is expected that the more instruments you turn ON, the more overhead you’ll have.

The advice I give my customers is that when in doubt, only turn ON the instruments that are required to troubleshoot your issue. Many of them ask: what exactly are the overhead costs for one instrumentation or another? I believe the best answer is “test on your system!” No generic benchmark can exactly repeat a workload on your site. But while I was working on the “OpenSource Databases on Big Machines” project, I decided to test the performance of Performance Schema as well.

I only tested a Read/Write workload. I used the same fast machine (144 CPU cores), the same MySQL options and the same SysBench commands that I described in this post. The option innodb_flush_method was changed to O_DIRECT, because it’s more reasonable for real-life workloads. I also upgraded the MySQL Server version to Oracle’s MySQL 5.7.17. The reason for the upgrade was to test if the issue described in this post is repeatable with latest Oracle MySQL server version. But since I tested Performance Schema, the effect on Percona Server for MySQL should be same.

I tested nine different scenarios:

  1. “All disabled”: Performance Schema is ON, but all instruments and consumers are disabled.
    update setup_consumers set enabled='no'; update setup_instruments set enabled='no';
  2. “All enabled”: Performance Schema is ON, and all instruments and consumers are enabled.
    update setup_instruments set enabled='yes'; update setup_consumers set enabled='yes';
  3. “Default”: Performance Schema is ON, and only default instruments and consumers are enabled.
  4. “MDL only”: only Metadata Lock instrumentation is enabled.
    update setup_consumers set enabled='no'; update setup_instruments set enabled='no'; update setup_consumers set enabled='yes' where name= 'global_instrumentation'; update setup_consumers set enabled='yes' where name= 'thread_instrumentation'; update setup_instruments set enabled='yes' where name='wait/lock/metadata/sql/mdl';
  5. “Memory only”: only Memory instrumentation enabled.
    update setup_consumers set enabled='no'; update setup_instruments set enabled='no'; update setup_consumers set enabled='yes' where name= 'global_instrumentation'; update setup_consumers set enabled='yes' where name= 'thread_instrumentation'; update setup_instruments set enabled='yes' where name like 'memory%';
  6. “Stages and Statements”: only Stages and Statements instrumentation enabled.
    update setup_consumers set enabled='no'; update setup_instruments set enabled='no'; update setup_consumers set enabled='yes' where name= 'global_instrumentation'; update setup_consumers set enabled='yes' where name= 'thread_instrumentation'; update setup_instruments set enabled='yes' where name like 'statement%'; update setup_consumers set enabled='yes' where name like 'events_statements%'; update setup_instruments set enabled='yes' where name like 'stage%'; update setup_consumers set enabled='yes' where name like 'events_stages%';
  7. “Stages only”: only Stages instrumentation enabled.
    update setup_consumers set enabled='no'; update setup_instruments set enabled='no'; update setup_consumers set enabled='yes' where name= 'global_instrumentation'; update setup_consumers set enabled='yes' where name= 'thread_instrumentation'; update setup_instruments set enabled='yes' where name like 'stage%'; update setup_consumers set enabled='yes' where name like 'events_stages%';
  8. “Statements only”: only Statements instrumentation enabled.
    update setup_consumers set enabled='no'; update setup_instruments set enabled='no'; update setup_consumers set enabled='yes' where name= 'global_instrumentation'; update setup_consumers set enabled='yes' where name= 'thread_instrumentation'; update setup_instruments set enabled='yes' where name like 'statement%'; update setup_consumers set enabled='yes' where name like 'events_statements%';
  9. “Waits only”: only Waits instrumentation enabled.
    update setup_consumers set enabled='no'; update setup_instruments set enabled='no'; update setup_consumers set enabled='yes' where name= 'global_instrumentation'; update setup_consumers set enabled='yes' where name= 'thread_instrumentation'; update setup_instruments set enabled='yes' where name like 'wait%' ; update setup_consumers set enabled='yes' where name like 'events_waits%';

Here are the overall results.

As you can see, some instrumentation only slightly affects performance, while others affect it a lot. I created separate graphs to make the picture clearer.

As expected, enabling all instrumentation makes performance lower:

Does this mean to use Performance Schema, you need to start the server with it ON and then disable all instruments? No! The default options have very little effect on performance:

The same is true for Metadata Locks, Memory and Statements instrumentation:

Regarding statements, I should note that I used prepared statements (which are instrumented in version 5.7). But it makes sense to repeat the tests without prepared statements.

The Stages instrumentation starts affecting performance:

However, the slowdown is reasonable and it happens only after we reach 32 concurrent threads. It still provides great insights on what is happening during query execution.

The real performance killer is Waits instrumentation:

It affects performance close to the same way as all instruments ON.

Conclusion

Using Performance Schema with the default options, Memory, Metadata Locks and Statements instrumentation doesn’t have a great impact on read-write workload performance. You might notice slowdowns with Stages instrumentation after reaching 32 actively running parallel connections. The real performance killer is Waits instrumentation. And even with it on, you will start to notice a performance drop only after 10,000 transactions per second.

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ProxySQL Admin Configuration

January 25, 2017 - 3:15pm

ProxySQL Admin (proxysql-admin) is a powerful tool for configuring Percona XtraDB Cluster nodes into ProxySQL. The proxysql-admin tool comes with the ProxySQL package from Percona apt/yum repositories.

ProxySQL 1.3.2-1 is now available from the Percona repositories. This release is based on ProxySQL v1.3.2a and introduces the following new changes: proxysql-admin_v1.3.2a.md.

Installing on Red Hat or CentOS

If you are running an RPM-based Linux distribution, use the yum package manager to install ProxySQL and proxysql-admin from the official Percona software repository.

First, if your system does not already have the Percona’s yum repository configured, please run the following command:

$ sudo yum install http://www.percona.com/downloads/percona-release/redhat/0.1-4/percona-release-0.1-4.noarch.rpm

Next, install the proxysql/proxysql-admin package:

$ sudo yum install proxysql

Installing on Debian or Ubuntu

If you are running a DEB-based Linux distribution, use the apt package manager to install ProxySQL and proxysql-admin from the official Percona software repository.

First, if your system does not already have the Percona’s apt repository configured, please fetch the repository package:

$ wget https://repo.percona.com/apt/percona-release_0.1-4.$(lsb_release -sc)_all.deb

Next, install the repository package:

$ sudo dpkg -i percona-release_0.1-4.$(lsb_release -sc)_all.deb

Then update the local apt cache:

$ sudo apt-get update

Finally, install the proxysql/proxysql-admin package:

$ sudo apt-get install proxysql

Pre-Requisites

  • ProxySQL and Percona XtraDB Cluster should be up and running.
  • For security purposes, please make sure to change the default user settings in the ProxySQL configuration file. It is recommend you use –config-file to run the proxysql-admin script.

This script will accept two different options to configure Percona XtraDB Cluster nodes;

1) −−enable

This option configures Percona XtraDB Cluster nodes into the ProxySQL database, and add two cluster monitoring scripts into the ProxySQL scheduler table for checking the cluster status.

_scheduler script info:

  • proxysql_node_monitor: checks cluster node membership, and re-configures ProxySQL if cluster membership changes occur
  • proxysql_galera_checker: checks desynced nodes, and temporarily deactivates them. It will also add two new users into the Percona XtraDB Cluster with the USAGE privilege. One monitors cluster nodes through ProxySQL, and the other connects to Cluster node via the ProxySQL console. Please make sure to use super user credentials from Percona XtraDB Cluster to setup the default users.
$ sudo proxysql-admin --config-file=/etc/proxysql-admin.cnf --enable This script will assist with configuring ProxySQL (currently only Percona XtraDB cluster in combination with ProxySQL is supported) ProxySQL read/write configuration mode is singlewrite Configuring ProxySQL monitoring user.. ProxySQL monitor username as per command line/config-file is monitor User 'monitor'@'127.%' has been added with USAGE privilege Configuring the Percona XtraDB Cluster application user to connect through ProxySQL Percona XtraDB Cluster application username as per command line/config-file is proxysql_user Percona XtraDB Cluster application user 'proxysql_user'@'127.%' has been added with the USAGE privilege, please make sure to the grant appropriate privileges Adding the Percona XtraDB Cluster server nodes to ProxySQL You have not given the writer node info through the command line or in the config-file. Please enter the writer-node info (eg : 127.0.0.1:3306): 127.0.0.1:25000 ProxySQL configuration completed! ProxySQL has been successfully configured to use with Percona XtraDB Cluster You can use the following login credentials to connect your application through ProxySQL mysql --user=proxysql_user --password=***** --host=127.0.0.1 --port=6033 --protocol=tcp $ mysql> select hostgroup_id,hostname,port,status,comment from mysql_servers; +--------------+-----------+-------+--------+---------+ | hostgroup_id | hostname | port | status | comment | +--------------+-----------+-------+--------+---------+ | 11 | 127.0.0.1 | 25400 | ONLINE | READ | | 10 | 127.0.0.1 | 25000 | ONLINE | WRITE | | 11 | 127.0.0.1 | 25100 | ONLINE | READ | | 11 | 127.0.0.1 | 25200 | ONLINE | READ | | 11 | 127.0.0.1 | 25300 | ONLINE | READ | +--------------+-----------+-------+--------+---------+ 5 rows in set (0.00 sec) mysql>

2. −−disable

This option removes Percona XtraDB Cluster nodes from ProxySQL and stops the ProxySQL monitoring daemon.

$ proxysql-admin --config-file=/etc/proxysql-admin.cnf --disable ProxySQL configuration removed! $

Extra options

i) −−mode

This option sets up read/write mode for Percona XtraDB Cluster nodes in the ProxySQL database, based on the hostgroup. For now, the only supported modes are loadbal and singlewrite. singlewrite is the default mode, and it accepts writes only on one single node (and this node can be provided either interactively or by using the –write-node to specify the hostname and the port number for the one single write node). All other remaining nodes will be read-only and accept only read statements. The mode loadbal, on the other hand, is a load balanced set of evenly weighted read/write nodes.

singlewrite mode setup:

$ sudo grep "MODE" /etc/proxysql-admin.cnf export MODE="singlewrite" $ $ sudo proxysql-admin --config-file=/etc/proxysql-admin.cnf --write-node=127.0.0.1:25000 --enable ProxySQL read/write configuration mode is singlewrite [..] ProxySQL configuration completed! $ mysql> select hostgroup_id,hostname,port,status,comment from mysql_servers; +--------------+-----------+-------+--------+---------+ | hostgroup_id | hostname | port | status | comment | +--------------+-----------+-------+--------+---------+ | 11 | 127.0.0.1 | 25400 | ONLINE | READ | | 10 | 127.0.0.1 | 25000 | ONLINE | WRITE | | 11 | 127.0.0.1 | 25100 | ONLINE | READ | | 11 | 127.0.0.1 | 25200 | ONLINE | READ | | 11 | 127.0.0.1 | 25300 | ONLINE | READ | +--------------+-----------+-------+--------+---------+ 5 rows in set (0.00 sec) mysql>

loadbal mode setup:

$ sudo proxysql-admin --config-file=/etc/proxysql-admin.cnf --mode=loadbal --enable This script will assist with configuring ProxySQL (currently only Percona XtraDB cluster in combination with ProxySQL is supported) ProxySQL read/write configuration mode is loadbal [..] ProxySQL has been successfully configured to use with Percona XtraDB Cluster You can use the following login credentials to connect your application through ProxySQL mysql --user=proxysql_user --password=***** --host=127.0.0.1 --port=6033 --protocol=tcp $ mysql> select hostgroup_id,hostname,port,status,comment from mysql_servers; +--------------+-----------+-------+--------+-----------+ | hostgroup_id | hostname | port | status | comment | +--------------+-----------+-------+--------+-----------+ | 10 | 127.0.0.1 | 25400 | ONLINE | READWRITE | | 10 | 127.0.0.1 | 25000 | ONLINE | READWRITE | | 10 | 127.0.0.1 | 25100 | ONLINE | READWRITE | | 10 | 127.0.0.1 | 25200 | ONLINE | READWRITE | | 10 | 127.0.0.1 | 25300 | ONLINE | READWRITE | +--------------+-----------+-------+--------+-----------+ 5 rows in set (0.01 sec) mysql>

ii) −−node-check-interval

This option configures the interval for monitoring via the proxysql_galera_checker script (in milliseconds):

$ proxysql-admin --config-file=/etc/proxysql-admin.cnf --node-check-interval=5000 --enable

iii) −−adduser

This option aids with adding the Percona XtraDB Cluster application user to the ProxySQL database:

$ proxysql-admin --config-file=/etc/proxysql-admin.cnf --adduser Adding Percona XtraDB Cluster application user to ProxySQL database Enter Percona XtraDB Cluster application user name: root Enter Percona XtraDB Cluster application user password: Added Percona XtraDB Cluster application user to ProxySQL database! $

iv) −−test-run

This option sets up a test/dummy proxysql configuration:

$ sudo proxysql-admin --enable --quick-demo You have selected the dry test run mode. WARNING: This will create a test user (with all privileges) in the Percona XtraDB Cluster & ProxySQL installations. You may want to delete this user after you complete your testing! Would you like to proceed with '--quick-demo' [y/n] ? y Setting up proxysql test configuration! Do you want to use the default ProxySQL credentials (admin:admin:6032:127.0.0.1) [y/n] ? y Do you want to use the default Percona XtraDB Cluster credentials (root::3306:127.0.0.1) [y/n] ? n Enter the Percona XtraDB Cluster username (super user): root Enter the Percona XtraDB Cluster user password: Enter the Percona XtraDB Cluster port: 25100 Enter the Percona XtraDB Cluster hostname: localhost ProxySQL read/write configuration mode is singlewrite Configuring ProxySQL monitoring user.. User 'monitor'@'127.%' has been added with USAGE privilege Configuring the Percona XtraDB Cluster application user to connect through ProxySQL Percona XtraDB Cluster application user 'pxc_test_user'@'127.%' has been added with ALL privileges, this user is created for testing purposes Adding the Percona XtraDB Cluster server nodes to ProxySQL ProxySQL configuration completed! ProxySQL has been successfully configured to use with Percona XtraDB Cluster You can use the following login credentials to connect your application through ProxySQL mysql --user=pxc_test_user --host=127.0.0.1 --port=6033 --protocol=tcp $ mysql> select hostgroup_id,hostname,port,status,comment from mysql_servers; +--------------+-----------+-------+--------+---------+ | hostgroup_id | hostname | port | status | comment | +--------------+-----------+-------+--------+---------+ | 11 | 127.0.0.1 | 25300 | ONLINE | READ | | 10 | 127.0.0.1 | 25000 | ONLINE | WRITE | | 11 | 127.0.0.1 | 25100 | ONLINE | READ | | 11 | 127.0.0.1 | 25200 | ONLINE | READ | +--------------+-----------+-------+--------+---------+ 4 rows in set (0.00 sec) mysql>

We hope you enjoy ProxySQL Admin!

Webinar Thursday January 26, 2017: Overcoming the Challenges of Databases in the Cloud

January 24, 2017 - 12:02pm

Please join Percona’s Jon Tobin, Director of Solution Engineering at Percona, and Rob Masson, Solutions Architect Manager at ScaleArc, on Thursday, January 26, 2017, at 9:00 am PST / 12:00 pm EST (UTC-8) for their webinar “Overcoming the Challenges of Databases in the Cloud.”

Enterprises enjoy the flexibility and simplified operations of using the cloud, but applying those advantages to database workloads has proven challenging. Resource contention, cross-region failover and elasticity at the data tier all introduce limitations. In addition, cloud providers support different services within their database offerings.

Jon and Rob’s webinar is a discussion on how to overcome these databases in the cloud challenges. You’ll learn:

  • The differences between IaaS and PaaS
  • How AWS, Azure, and Google Cloud stack up
  • Tricks for managing smaller database instances
  • Tips for achieving cross-region failover
  • Best practices for hybrid deployments

Register for the webinar here.

Jon Tobin, Director of Solution Engineering, Percona

When not saving kittens from sequoias or helping the elderly across busy intersections, Jon Tobin is Percona’s Director of Solutions Engineering. He has spent over 15 years in the IT industry. For the last six years, Jon has been helping innovative IT companies assess and address customer’s business needs through well-designed solutions.

Robert Masson, Solutions Architect Manager, ScaleArc

Over the past ten years, Robert has been working with leading edge Product Companies that are defining the future of Computing. When at EMC,  he led an Advanced Development Team that explored the capabilities of new technologies and helped to drive innovation within a world leader in information management technologies. Robert also was the Director of Research on the East Coast and interfaced with researchers at MIT, Harvard and Boston University (among others).

Currently, Robert works with the world leader in cloud management platforms, allowing customers to manage assets easily and securely across disparate platforms seamlessly. He gets to work hands-on with implementation teams and business drivers to help understand their needs, design their organizations and implement that vision into a game-changing infrastructure and toolset.

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