In this blog post, we talk about how existing client connections are handled by the Tungsten Connector when a manual master role switch is invoked and how to adjust that behavior.

When a graceful switch is invoked via cctrl or the Tungsten Dashboard, by default the Connector will wait for five (5) seconds to allow in-flight activities to complete before forcibly disconnecting all active connections from the application side, no matter what type of query was in use.

If connections still exist after the timeout interval, they are forcibly closed, and the application will get back an error.

This configuration setting ONLY applies to a manual switch. During a failover caused by loss of MySQL availability, there is no wait and all connections are force-closed immediately.

This timeout is adjusted via the tpm option …

In this blog post, we talk about the basic function and features of the Tungsten Connector.

The Tungsten Connector is an intelligent MySQL proxy that provides key high-availability and read-scaling features. This includes the ability to route MySQL queries by inspecting them in-flight.

The most important function of the Connector is failover handling. When the cluster detects a failed master because the MySQL server port is no longer reachable, the Connectors are signaled and traffic is re-routed to the newly-elected Master node.

Next is the ability to route MySQL queries based on various factors. In the default Bridge mode, traffic is routed at the TCP layer, and read-only queries must be directed to a different port (normally 3306 for writes and 3307 for reads).

There are additional modes, Proxy/Direct and …

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

There 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 …

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 …

We have identified an issue in a script that is executed as part of the Tungsten Clustering solution. The script itself executes a small query against the internal tables used by the replicator in order to help identify the current status and latency of the replication process. We believe this script may occasionally fail under some very specific conditions, which would not normally be an issue, but the knock on effect is to create Out of Memory errors and instability in the way identifying the current replication state is handled.

The issue has been fixed in the upcoming 6.0.1 and 5.3.2 releases, but we have identified that customers on versions of the Tungsten Clustering solution from v4.0 upwards would benefit from using an updated version of the script.

If you are using Tungsten Clustering 4.x or higher, it is recommended that you apply this patch to improve the stability of your clustering …

Continuent have been a long term sponsor of the Percona Live conference, and the MySQL conference as it was before that, for many years. We have attended the conference both as a Diamond sponsor, and members of our staff attending and presenting our products and experience at the conference.

The nature of these conferences always changes over time, and we have seen over the last few years how the Percona Live conference has moved from being a pure MySQL conference to an open source database conference. Although Continuent continue to provide open source software and integrate with many open source databases, our core operation still revolves around MySQL clustering and replication for MySQL and Oracle.

Continuent is also evolving and changing and we are increasingly deploying and moving towards pure cloud-based environments, building and developing products that are used on the cloud or …

Welcome to the January 2018 Continuent Product Management newsletter. It’s the start of the year, and so a good opportunity to look forward, as well as back a little to see how we did. Let’s start with the immediate future first.

• Tungsten Clustering 6.0 is Coming!
• Tungsten Replicator 6.0 is Also Coming!
• Looking at the Year Ahead
• Tungsten Backup, Tungsten Connector
• Tungsten GUI
• End-of-Life Policy
• Release Schedule
• Internal Tweaks

Tungsten Clustering 6.0 is Coming!

The development and restructuring of the product has taken a year to come to fruition, as there are quite a lot of different components, but the new version of Tungsten Clustering 6.0 is due out in February and we’re really pleased with the result.

The focus of this release of the product is to unify the components that previously …

You may know Continuent Tungsten for our highly advanced MySQL replication tool, Tungsten Replicator, and for our state-of-the-art MySQL clustering solution, Tungsten Clustering. Our solutions are used by leading SaaS vendors, e-commerce, financial services and telco customers.

But there are more, many more, Tungsten deployments out there. Tungsten Replicator can be used for real-time data