A quick look at ProxySQL

There is a lot of buzz in the MySQL community around ProxySQL, an open-source SQL-aware proxy. I was lucky enough to give a ProxySQL Tutorial at PerconaLive Amsterdam 2016 with the creator of ProxySQL, René Cannaò.

Some of ProxySQL’s features include:

• Query rules based on Google’s RE2-style regex
• Failover detection
• Connection multiplexing

ProxySQL’s approach to implementing regex-style query rules opens the door to some pretty fascinating possibilities. Just to name a few examples:

• Read/write splitting between the write master and read slaves
• Query firewall, for those times you wish you could prevent queries from hitting the database. Perhaps you are …

Take Percona’s poll on what database technologies you use in your environment.

Different databases get designed for different scenarios. Using one database technology for every situation doesn’t make sense, and can lead to non-optimal solutions for common issues. Big data and IoT applications, high availability, secure backups, security, cloud vs. on-premises deployment: each have a set of requirements that might need a special technology. Relational, document-based, key-value, graphical, column family – there are many options for many problems. More and more, database environments combine more than one solution to address the various needs of an enterprise or application (known as polyglot persistence).

Please take a few seconds and answer the following poll on database technologies. Which are you using? Help …

This release introduces a new major feature – GUI transaction support – as well as some minor features and bug fixes.

Changes as compared to MySQL GUI 12.2.6 include:

Features:

* GUI transactions support. This new feature is available in Enterprise and Ultimate editions. Also please see note below.
* Added a tooltip on column headers in Data tab informing about column name, column type and length. In Result tab the tooltip will display column name only, as the result returned by MySQL does not have information of storage type details.
* Added GUI support for index-level comments in CREATE/ALTER TABLE.

Bug Fixes:

* Fixed an issue where GUI could ‘hang’ when executing queries with very large subqueries.
* Fixed an issue with the …

I’ve been wanting an easy way to play around with MySQL Cluster lately, the latest 7.5 release is now based on the MySQL 5.7 branch, so it also has the sys schema packaged, adding more areas for me to add sys integration that is more cluster specific – especially given all of the new tables that were added within ndbinfo.

There’s a couple of examples of docker images that wrap older MySQL Cluster packages out there, but:

• Nothing up to date, I wanted to use MySQL Cluster 7.5.4
• Nothing that uses docker networks, rather than the old link style
• Nothing that helps to orchestrate starting the containers, I don’t want anything fancy, just to start a Cluster of a certain shape (n of …

Here is the third in a series of posts about CTEs, a new feature of MySQL 8.0, available in this Labs release. In the first post we had explored the new SQL syntax, and in the second we had applied it to generating series.…

Disk space issues are common, and they’re often difficult to solve quickly. One way to recover some space is by enabling InnoDB compression.

First, of course, you want to make sure you’ve covered alternative solutions. Can you archive data? Do partitioning/sharding? These generally involve application changes and can take longer.

You may need to first do conversion to InnoDB.

While compression is available for MyISAM via myisampack, and this can be useful for some use cases (for example, if you are rotating out tables on a monthly basis), it makes the tables read-only, so generally you will want to first convert MyISAM tables to InnoDB.

Things to watch for in the schema: After working on functional and performance issues with full-text indexes after conversion to InnoDB, I wouldn’t recommend it. Application changes are also required to rewrite queries. You can consider outsourcing these to a tool …

InnoDBOnline buffer pool resize:

• Configure innodb_buffer_pool_size offline (at startup) or online, while the server is running 

• The operation is performed in chunks

• Chunk size is defined by the innodb_buffer_pool_chunk_size configuration option      

• Buffer pool size always be equal to or a multiple of innodb_buffer_pool_chunk_size * innodb_buffer_pool_instances

• Default innodb_buffer_pool_chunk_size is 128M

Reference:


https://dev.mysql.com/doc/refman/5.7/en/innodb-buffer-pool-resize.html



Online RENAME INDEX operation:

• ALTER TABLE RENAME INDEX requires only meta-data change.

Reference:

…

In this blog post, we’ll look at how replication triggers a Performance Schema issue on Percona XtraDB Cluster.

During an upgrade to Percona XtraDB Cluster 5.6, I faced an issue that I wanted to share. In this environment, we set up three Percona XtraDB Cluster nodes (mostly configured as default), copied from a production server. We configured one of the members of the cluster as the slave of the production server.

During the testing process, we found that a full table scan query was taking four times less in the nodes where replication was not configured. After reviewing mostly everything related to the query, we decided to use perf.

We executed:

perf record -a -g -F99 -p $(pidof mysqld) -- sleep 60

And the query in another terminal a couple of times. …

The event takes place on 3-4 November 2016 at Olympia Conference Centre, London and will provide you with the tools to deliver your most effective data-driven strategy.

We will be exhibiting on stand 514 and we would be delighted
to speak with you over the 2 days.

Come over and speak to us about how your business can benefit from our open source database solutions. We will be offering demos of our products and will show you how your business can benefit from them.

…

The pt-online-schema-change tool has been a workhorse for years, allowing MySQL DBAs to alter tables with minimal impact to application workload, and before MySQL had native online alter capabilities. Although consistently grateful for the tool’s existence, I never liked the messiness of having to use and clean up triggers, and most DBAs have a horror story or two to tell about using any of the online alter methods.

When Github’s online schema transmogrifer (gh-ost; https://github.com/github/gh-ost) was released, then, I jumped on the chance to test it out.

Following are my testing notes. I tried out the flags available to run gh-ost from different locations in a replication setup, both functionally and under load. The load applied was via mysqlslap, using a …