In this blog post, we talk about how query connections are handled by the Tungsten Connector, especially read-only connections.

The are multiple ways to configure session handling in the Connector. The three main modes are Bridge, Proxy/Direct and Proxy/SmartScale.

In Bridge mode, the data source to connect to is chosen ONCE for the lifetime of the connection, which means that the selection of a different node will only happen if a NEW connection is opened through the Connector.

So if your application reuses its connections, all traffic sent through that session will continue to land on the selected read slave, i.e., when using connection pooling.

http://docs.continuent.com/tungsten-clustering-6.0/connector-bridgemode.html

The key difference is in how the slave latency checking is handled: …

Did you know that Continuent Clustering supports having clusters at multiple sites world-wide with active-active replication meshing them together?

Not only that, but we support a flexible hybrid model that allows for a blended architecture using any combination of node types. So mix-and-match your highly available database layer on bare metal, Amazon Web Services (AWS), Azure, Google Cloud, VMware, etc.

The possibilities are endless, as is the business value. This strong topology allows you to have all the benefits of high availability with local reads and writes, while spreading that data globally to be accessible in all regions. Latency is limited only by the WAN link and the speed of the target node.

This aligns perfectly with the distributed Software-as-a-Service (SaaS) model where customers and data span the globe. Applications have access to ALL the …

MySQL InnoDB Cluster is an Oracle High Availability solution that can be easily installed over MySQL to provide high availability with multi-master capabilities and automatic failover. In the previous post we presented the first component of InnoDB Cluster, group replication. Now we will go through the second component, MySQL Router.  We will address MySQL Shell in a final instalment of this three-part series. By then, you should have a good overview of the features offeed by MySQL InnoDB Cluster.

MySQL Router

This component is responsible for distributing the traffic between members of the cluster. It is a proxy-like solution to hide cluster topology from applications, so applications don’t …

MySQL 8.0 has come with a list of new features for DBA’s ,we will discuss the new feature in MySQL 8.0 which supports Descending index.Prior to MySQL 8.0 (i.e MySQL 5.6 and 5.7) creating desc index syntax was supported but desc keyword was ignored, Now in MySQL 8.0 release descending index is extended are supported.

What is index?

• Indexes play an important role in performance optimization  and they are used frequently to speed up access to particular data and reduce disk I/O operations .
• To understand index easily you can imagine a book,every book has an index with content referring to a page number.If you want to search something in a book you first refer to the index and get the page number and then get the information in the page,like this the indexes in MySQL will tell you the row with matching data.

…

Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

Hello again after the hiatus last week. I’m en route to Portland for OSCON, and am very excited as it is the conference’s 20th anniversary! I hope to see some of you at my talk on July 19.

On July 18, join me for a webinar: MariaDB 10.3 vs. MySQL 8.0 at 9:00 AM PDT (UTC-7) / 12:00 PM EDT (UTC-4). I’m also feverishly working on an update to MySQL vs. MariaDB: Reality Check, now that both MySQL 8.0 and MariaDB Server 10.3 are generally available.

Rather important: …

What if I want the cluster to be less sensitive to network, especially WAN latency?

Continuent Clustering supports having clusters at multiple sites with active-active replication meshing them together.

This is extraordinarily powerful, yet at times high network latency can make it harder for messaging between the sites to arrive in a timely manner.

This is evidenced by seeing the following in the Manager log files named tmsvc.log:

2018/07/08 16:51:05 | db3 |  INFO [Rule_0604$u58$_DETECT_UNREACHABLE_REMOTE_SERVICE1555959201] - CONSEQUENCE: [Sun Jul 08 16:51:04 UTC 2018] CLUSTER global/omega(state=UNREACHABLE)
...
2018/07/08 16:51:42 | db3 |  INFO [Rule_2025$u58$_REPORT_COMPONENT_STATE_TRANSITIONS1542395297] - CLUSTER 'omega@global' STATE TRANSITION UNREACHABLE => ONLINE

The delta is 37 seconds in the above example between state=UNREACHABLE and UNREACHABLE => ONLINE

The default …

Recently, Dimitri published the results of measuring MySQL 8.0 on Intel Optane storage device. In this blog post, I wanted to look at this in more detail and explore the performance of MySQL 8, MySQL 5.7 and Percona Server for MySQL using a similar set up. The Intel Optane is a very capable device, so I was puzzled that Dimitri chose MySQL options that are either not safe or not recommended for production workloads.

Since we have an Intel Optane in our labs, I wanted to run a similar benchmark, but using settings that we would recommend our customers to use, namely:

• use innodb_checksum
• use innodb_doublewrite
• use binary logs with sync_binlog=1
• enable (by default) Performance …

Oracle has done a great technical work with MySQL. Specifically a nice job has been done around security. There is one useful feature that exists in Oracle MySQL and that currently does not exist in MariaDB. Oracle MySQL offers the possibility from within the server to generate asymetric key pairs. It is then possible use [...]

MySQL stored procedures, functions and triggers are tempting constructs for application developers. However, as I discovered, there can be an impact on database performance when using MySQL stored routines. Not being entirely sure of what I was seeing during a customer visit, I set out to create some simple tests to measure the impact of triggers on database performance. The outcome might surprise you.

Why stored routines are not optimal performance wise: short version

Recently, I worked with a customer to profile the performance of triggers and stored routines. What I’ve learned about stored routines: “dead” code (the code in a branch which will never run) can still significantly slow down the response time of a function/procedure/trigger. We will need to be careful to clean up what we do not need.

Profiling MySQL stored functions

Let’s compare these four simple stored functions (in MySQL 5.7): …

In the old days, when we wanted to strengthen our skills the only option was to buy a good book. Nowadays one can find a lot of resources on the Internet, however quality is often poor. Fortunately there are still some great people who are brave enough to write new books that will help a new generation of women and men to build modern applications with MySQL the world's most popular open source database. Let me introduce you 3 MySQL books : Introducing the MySQL 8 Document Store / MySQL and JSON: A Practical Programming Guide / Pro MySQL NDB Cluster