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Displaying posts with tag: replicator (reset)
Comparing Replication Technologies for MySQL Clustering: Part 1

Overview

Clustering provides high availability and disaster recovery, along with the ability to read-scale both locally and globally. Some clusters even provide active/active capabilities, which others have a single master.

Real time database replication is a must for clustering and other key business purposes, like reporting. There are a number of replication technologies available for MySQL, and some are even bundled into various solutions. When choosing a replication methodology, it is paramount to understand just how the data moves from source to target. In this blog post, we will examine how asynchronous, synchronous, and “semi-synchronous” replication behave when used for clustering. Also, we will explore how …

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Handling Bi-Directional Replication between Tungsten Clusters and AWS Aurora

Overview The Skinny

In this blog post, we explore the correct way to implement bi-directional Tungsten Replication between AWS Aurora and Tungsten Clustering for MySQL databases.

Background The Story

When we are approached by a prospect interested in using our solutions, we are proud of our pre-sales process by which that we engage at a very deep technical level to ensure the we provide the best possible solution to meet with the prospect’s requirements. This involves an in-depth hands-on POC, in addition to the significant time and effort we spend building and testing the solution architectures in our lab environment as part of the proposal process.

From time to time, we are presented with requirements that are not always quite so straight forward. Just recently we faced such a situation. A …

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10 Reasons Why Tungsten Clustering Beats the DIY Approach for Geo-Distributed MySQL Deployments

Why does the DIY approach fail to deliver vs. the Tungsten Clustering solution for geo-distributed MySQL multimaster deployments?

Before we dive into the 10 reasons, note why commercially-supported enterprise software is less risky and in fact less costly:

  • The labor time spent building and maintaining a DIY solution costs more than a supported solution that just works.
  • There is documentation, training, support, so your mission-critical process is never dependent upon an irreplaceable individual.
  1. Tungsten Clustering is a complete solution, comprised of the Replicator, Manager and Connector components
    • With DIY, you must first decide the architecture, then select the individual tools to handle each layer of the topology. …
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Enabling Autorecovery for the Tungsten Replicator

The Replicator is a critical piece of the Tungsten Clustering solution for MySQL / MariaDB, as well as its own stand-alone data replication product. Automatic recovery is a feature that enables the Replicator to go back online in the event of a transient failure. In this blog we discuss how to enable Automatic Recovery. For more information about Auto-Recovery, please click here to visit the online documentation page.

The Question Recently, a customer asked us:

We see that the replicators receive a transaction which has a deadlock error in it:

pendingError : Event application failed: seqno=82880882 fragno=0 message=java.sql.SQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction

If one performs a service online, it comes back online without issue and continues …

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Tungsten Clustering 5.4.0 and Tungsten Replicator 5.4.0 Released

Continuent is pleased to announce that the following new software releases are now available:

  • Tungsten Clustering version 5.4.0
  • Tungsten Replicator version 5.4.0

Releases 5.4.0 is significant in that it introduces MySQL 8 support, along with many new features, stability improvements and bug fixes.

Highlights common to both products:

Improvements, new features and functionality

  • Two new utility scripts have been added to the release to help with setting the Replicator position:
    • tungsten_find_position, which assists with locating information in the THL based on the provided MySQL binary log event position and outputs a dsctl set
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Tungsten Clustering 6.1.0 and Tungsten Replicator 6.1.0 Released

Continuent is pleased to announce that the following new software releases are now available:

  • Tungsten Clustering version 6.1.0
  • Tungsten Replicator version 6.1.0

Release 6.1.0 is significant in that it introduces MySQL 8 support, along with many new features, stability improvements and bug fixes.

Highlights common to both products:

Improvements, new features and functionality

  • Two new utility scripts have been added to the release to help with setting the Replicator position:
    • tungsten_find_position, which assists with locating information in the THL based on the provided MySQL binary log event position and outputs a dsctl set command …
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How to move the Relay role to another node in a Composite Tungsten Cluster

The Question Recently, a customer asked us:

How would we manually move the relay role from a failing node to a slave in a Composite Tungsten Cluster passive site?

The Answer The Long and the Short of It

There are two ways to handle this procedure manually when the usual switch command fails to work as expected. One is short and reasonably automated, and the other is much more detailed and manual.

Of course, the usual procedure is to just issue the switch command in the passive cluster:

use west
set policy maintenance
switch
set policy automatic

The below article describes what to do when the switch command does not move the relay role to another node.

SHORT

Below is the list of cctrl commands that would be run for the basic, short version, which (aside from handling policy changes) is really only …

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The Fast Way to Import CSV Data Into a Tungsten Cluster

The Question Recently, a customer asked us:

After importing a new section of user data into our Tungsten cluster, we are seeing perpetually rising replication lag. We are sitting at 8.5hrs estimated convergence time after importing around 50 million rows and this lag is climbing continuously. We are currently migrating some of our users from a NoSQL database into our Tungsten cluster. We have a procedure to write out a bunch of CSV files after translating our old data into columns and then we recursively send them to the write master using the mysql client. Specifically our import SQL is doing LOAD DATA LOCAL INFILE and the reading in a large CSV file to do the import. We have 20k records per CSV file and we have 12 workers which insert them in parallel.

Simple Overview The Skinny

In cases like this, the slaves are having trouble with the database unable to keep up with the apply stage …

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Troubleshooting Data Differences in a MySQL Database Cluster

Overview The Skinny

From time to time we are asked how to check whether or not there are data discrepancies between Master/Slave nodes within a MySQL (or MariaDB) cluster that’s managed with Tungsten Clustering. This is always a challenging task, not least because we hope and believe that our replication mechanism would avoid such occurrences, that said there can be factors outside of our control that can appear to “corrupt” data – such as inadvertent execution of DML against a slave using a root level user account.

Tungsten Replicator, the core replication component in our Tungsten Clustering solution for MySQL (& MariaDB), is just that, a replicator – it takes transactions from the binary logs and replicates them around. The replicator isn’t a data synchronisation tool in that respect, the …

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Tungsten Clustering 6.0.5 and Tungsten Replicator 6.0.5 Released

Continuent is pleased to announce that Tungsten Clustering 6.0.5 and Tungsten Replicator 6.0.5 are now available!

Our v6.0.5 release fixes a number of bugs and introduces some new features, with improvements across the board in a variety of different components.

Some of the key improvements include:

  • A new Clustering utility script has been added to the release, tungsten_reset_manager, which assists with the graceful reset of the manager’s dynamic state files on disk.
  • Fixed an issue where the tpm command would allocate inconsistent THL listener ports for the Composite Multimaster (CMM) topology.
  • MySQL ping commands are now reconnected/retried upon “server gone away” error (Proxy mode ONLY).
  • mysql_checker_query script was returning …
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