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The Important Role of a Tungsten Rollback Error

The Question Recently, a customer asked us:

What is the meaning of this error message found in trepsvc.log?

2019/05/14 01:48:04.973 | mysql02.prod.example.com | [east - binlog-to-q-0] INFO pipeline.SingleThreadStageTask Performing rollback of possible partial transaction: seqno=(unavailable)

Simple Overview The Skinny

This message is an indication that we are dropping any uncommitted or incomplete data read from the MySQL binary logs due to a pending error.

The Answer Safety First

This error is often seen before another error and is an indication that we are rolling back anything uncommitted, for safety. On a master this is normally very little and would likely be internal transactions in the trep_commit_seqno table, for example.

As you may know with the replicator we always extract complete transactions, and so this particular message is …

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Critical Update for Percona Server for MySQL 5.6.44-85.0

This blog is an announcement for a Percona Server for MySQL 5.6.44-85.0-1

 

This is a CRITICAL update and the fix mitigates the issues described in CVE-2019-12301. If you upgraded packages on Debian/Ubuntu to 5.6.44-85.0-1, please upgrade to 5.6.44-85.0-2 or later and reset all MySQL root passwords.

 

Issue

On 2019-05-18 Percona discovered an issue with the Debian/Ubuntu 5.6.44-85.0-1 packages for Percona Server for MySQL. When the previous versions, upgraded to the new version PS 5.6.44-85.0-1 on deb based systems, the MySQL root password was removed allowing users to login to the upgraded server as MySQL root without specifying a password.

 

Scope

This issue is limited to users who upgraded with the Debian/Ubuntu package …

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Create CRUD Rest API using Spring Boot and JPA

This java rest api tutorial help to create CRUD rest api using spring boot application.The spring boot is the next level of spring framework.Its based on java spring framework.We will create maven type project and generating JAR build.

The Spring boot provides CLI to create and manage application.You can setup a spring boot project with almost zero configuration.

In this java rest tutorial, we’ll build a Restful CRUD API for employee module.This module have API to get all employee, get a single employee records based on id and delete employee record by id.

How To Create a New Spring Boot Project

The spring boot provides a web tool to create initial level spring boot application.We will go to https://start.spring.io/, Now enter the required details.

Once all the details are entered, You need to click Generate Project button to …

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Shinguz: Dropped Tables with FromDual Backup Manager

Some applications have the bad behaviour to CREATE or DROP tables while our FromDual Backup Manager (bman) backup is running.

This leads to the following bman error message:

/opt/mysql/product/5.7.26/bin/mysqldump --user=dba --host=migzm96i --port=3306 --all-databases --quick --single-transaction --flush-logs --triggers --routines --hex-blob --events | tee >(md5sum --binary >/tmp/checksum.23357.md5) | gzip -1
to Destination: /var/mysql/dumps/mysql96i/daily/bck_mysql96i_full_2019-05-22_06-50-01.sql.gz
ERROR: /opt/mysql/product/5.7.26/bin/mysqldump command failed (rc=253).
mysqldump: [Warning] Using a password on the command line interface can be insecure.
Error: Couldn't read status information for table m_report_builder_cache_157_20190521035354 ()
mysqldump: Couldn't execute 'show create …
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How to Automate Migration from Standalone MySQL to Galera Cluster using Ansible

Database migrations don’t scale well. Typically you need to perform a great deal of tests before you can pull the trigger and switch from old to new. Migrations are usually done manually, as most of the process does not lend itself to automation. But that doesn’t mean there is no room for automation in the migration process. Imagine setting up a number of nodes with new software, provisioning them with data and configuring replication between old and new environments by hand. This takes days. Automation can be very useful when setting up a new environment and provisioning it with data. In this blog post, we will take a look at a very simple migration - from standalone Percona Server 5.7 to a 3-node Percona XtraDB Cluster 5.7. We will use Ansible to accomplish that.

Environment Description

First of all, one important disclaimer - what we are going to show here is only a draft of what you might like to run in production. It does …

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No Ping Will Tear Us Apart – Enabling member auto-rejoin in Group Replication

With the release of version 8.0.16 of MySQL, we’ve added some features to the Group Replication (GR) plugin, in order to enhance its high-availability capacities. One of these features was the ability to enable a member that has left the group, under certain circumstances, to automatically rejoin it, without need of intervention by the user.…

Re-evaluating MySQL 8 Query Transformations Capabilities

I recently stumbled upon a very interesting post by Lukas Eder, where he describes 10 query transformations which do not depend on the database’s cost model. He posted it a couple of years ago, though when I read it, I assumed some portions of it may still be relevant today.

In the original post, several databases were tested to see if their internal optimizer will be able to automatically re-write the SQL queries and optimize them. In those tests, MySQL under-performed in several of the use cases (the tested version was MySQL 8.0.2, which was released on 2017-07-17).

Seeing those results, and given the previous evaluation was done almost two years ago, I thought that now can be a good chance to re-evaluate a few of those tests with the latest MySQL 8.0.16 (released on 2019-04-25), and demonstrate …

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Understanding Cross-Site Replication in a Tungsten Composite Multi-Master Cluster for MySQL, MariaDB and Percona Server

Overview The Skinny

In this blog post we will discuss how the managed cross-site replication streams work in a Composite Multi-Master Tungsten Cluster for MySQL, MariaDB and Percona Server.

Agenda What’s Here?

  • Briefly explore how managed cross-site replication works in a Tungsten Composite Multi-Master Cluster
  • Describe the reasons why the default design was chosen
  • Explain the pros and cons of changing the configuration
  • Examine how to change the configuration of the managed cross-site replicators

Cross-Site Replication A Very Brief Summary

In a standard Composite Multi-Master (CMM) deployment, the managed cross-site replicators pull Transaction History Logs (THL) from every remote cluster’s current master node. …

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How to fetch single row from database in php codeigniter

If you require to get only one record from database table using codeigniter query then you can do it using row we can easily return one row from database in codeigniterI will give you simple example of fetch single record from database using mysql codeigniterSometime we need to get only one

Flashback Recovery in MariaDB/MySQL Servers

In this blog, we will see how to do a flashback recovery or rolling back the data in MariaDB, MySQL and Percona.

As we know the saying  “All humans make mistakes”, following that in Database environment the data modified accidentally can bring havoc to any organisations.

Recover the lost data

  • The data can be recovered from the latest full backup or incremental backup when data size is huge it could take hours to restore it.
  • From backup of Binlogs.
  • Data can also be recovered from delayed slaves, this case would be helpful when the mistake is found immediately, within the period of delay.

We can use anyone of the above ways or other that can help to recover the lost data, but what really matters is, What is the …

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