When Tungsten Replicator extracts data, the information that has been extracted is written down into the Tungsten History Log, or THL. These files are in a specific format and they are used to store all of the extracted information in a format that can easily be used to recreate and generate data in a target.

Each transaction from the source is written into the THL as an event, so within a single THL file there will be one or more events stored. For each event, we record information about the overall transaction, as well as then information about the transaction itself. That event can contain one or more statements, or rows, or both. Because we don’t want to get an ever increasing single file, the replicator will also divide up the THL into multiple files to tmake the data easier to manage.

We’ll get down into the details soon, until then, let’s start by looking at the basics of the THL, files and sequence numbers and how to …

We are growing!

Consequently, Continuent needs additional talented staff.

We are currently looking for a person who would be a good fit for our “Database Clustering Technical Sales & Support Engineer” position, in the US Pacific timezone.

If you know someone who would be a good fit for this role and our company’s culture, please send them our way.

The Tungsten Replicator is an extraordinarily powerful and flexible tool capable of moving vast volumes of data from source to target.

In this blog post we will discuss one specific aspect of the THL (Transaction History Log) – the METADATA unsafe_for_block_commit flag.

What do you mean, Unsafe?

In a recent customer support case, we were asked the meaning of the unsafe_for_block_commit flag. For example, list the event information for sequence number 3481394254:

[tungsten@tr2-mysql01 (sandbox) ~]$ thl list -seqno 3481394254 | more
SEQ# = 3481394254 / FRAG# = 0 (last frag)
- TIME = 2018-09-16 06:52:47.0
- EPOCH# = 3480364140
- EVENTID = mysql-bin.001068:0000000294739578;622252
- SOURCEID = tr2-mysql01.sandbox.yourdomain.com
- METADATA = [mysql_server_id=1;unsafe_for_block_commit;dbms_type=mysql;tz_aware=true;service=brm;shard=shard_1736]
- TYPE = …

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 …

Continuent are pleased to announce that the new 5.3.1 release is now available for all our customers.

This is a key bug fix and feature release, the key component of which is the final piece of the support for extracting data types from MySQL 5.7 with the Geometry data type.

Key improvements within Tungsten Clustering:

• Full Support for MySQL data types with the addition of Geometry datatype
• Fixed an issue where large memory dumps could be collected during a failure
• Fixed some issues to ensure compatibility with upcoming products

Key improvements within Tungsten Replicator:

• Full Support for MySQL data types with the addition of Geometry datatype

It’s important to note that due to the addition of support for the geometry datatype, THL written with Geometry data will no longer be readable by …

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 …

Solaris Cluster is a multi-system, multi-site high availability and disaster recovery solution that manages the availability of applications services and data across local, regional and geographically dispersed data centers. The Solaris Cluster environment extends the Solaris Operating System into a cluster operating system.

If you are following the Solaris Cluster product and features, you would have noticed extreme innovation by Sun in the high availability and disaster recovery space since the time we released our first HA product many years ago. For well over a decade, Solaris Cluster has been a market leader for providing business continuity and disaster recovery solutions to all mission critical business applications, spanning all the major industry segments.

Continuing with our tradition of innovation, we are pleased to announce another release - "Solaris Cluster 3.2 11/09" - an update to the Solaris Cluster 3.2 …

Solaris Cluster is a multi-system, multi-site high availability and disaster recovery solution that manages the availability of applications services and data across local, regional and geographically dispersed data centers. The Solaris Cluster environment extends the Solaris Operating System into a cluster operating system.

If you are following the Solaris Cluster product and features, you would have noticed extreme innovation by Sun in the high availability and disaster recovery space since the time we released our first HA product many years ago. For well over a decade, Solaris Cluster has been a market leader for providing business continuity and disaster recovery solutions to all mission critical business applications, spanning all the major industry segments.

Continuing with our tradition of innovation, we are pleased to announce another release - "Solaris Cluster 3.2 11/09" - an update to the Solaris Cluster 3.2 …