This Log Buffer Edition includes blog posts from Oracle, SQL Server and MySQL.

Oracle:

In 12.2 you can: Convert a simple table to partitioned with multi-column automatic list partitions, partially indexed, with read only segments, filtering out unwanted data, online in one operation.

12c How to UN Expire Password for CDB Users

rman auxiliary (for duplicate)

How long will Oracle APEX remain an included feature of the Oracle Database?

How to easily delete files …

This Log Buffer Edition covers Oracle, SQL Server and MySQL.

Oracle:

Upgrade Existing TDE to Use New Unified Key Management in 12c Upgraded Database (non-cdb)

Instrumentation … not just for debugging

12.2 Index Deferred Invalidation (Atomica)

Collation in 12cR2 – when AA equals Å (or not?)

…

This Log Buffer Edition covers Oracle, SQL Server and MySQL.

Oracle:

Upgrade Existing TDE to Use New Unified Key Management in 12c Upgraded Database (non-cdb)

Instrumentation … not just for debugging

12.2 Index Deferred Invalidation (Atomica)

Collation in 12cR2 – when AA equals Å (or not?)

…

This Log Buffer Edition covers Oracle, SQL Server, MySQL.

Oracle:

A Sneak Peek at Oracle’s Chatbot Cloud Service and 5 Key Factors Necessary for Bot ROI

Oracle JET Hybrid – NavDrawer Template Menu/Header Structure

Oracle Enterprise Linux 6.6 AMI Available on AWS

Datascape Podcast Episode 9 – What’s Up with Oracle These Days?

Sequential Asynchronous calls in …

In this post I will explain how to transfer a multi terabyte size database between two MySQL instances using mydumper, which is a logical backup and restore tool that works in parallel. I will also cover the case where you need to transfer only a subset of data.

Big tables are often problematic because of the amount of time needed to do mysqldump/restore which is single threaded. It is not uncommon for this type of process to take several days.

From MySQL 5.6 and on, we also have transportable tablespaces, but there are some limitations with that approach.

Physical backups (e.g. xtrabackup) have the advantage to be faster, but there are some scenarios where you still need/want a logical backup (e.g migrating to RDS/Aurora/Google Cloud SQL).

Steps Install mydumper/myloader

The first thing …

Isolation levels are a rare subject in MySQL literature. The documentation provides a terse description and focuses mainly on locking issues, but does not discuss the semantics of each isolation level. This is not only a problem that affects MySQL documentation but also the SQL standard itself.

Both the lack of documentation and the absence of a deeper description of the expected behavior in the SQL standard make isolation levels a topic that is more assumed than known by database administrators and developers. In this blog post, I aim to help you understand how the default isolation level in MySQL works and show you some surprising facts about it.

But first let’s see how isolation levels are described in the standard: “The transaction isolation level of a SQL-transaction defines the degree to which the operations on SQL-data, or schemas in that SQL-transaction are affected by the effects of and can affect operations on …

Overview

In this post I will explain how to transfer a partitioned table using transportable tablespaces on MySQL 5.6. Note that the operation is not officially supported until MySQL 5.7, as the discard tablespace operation will fail if it is run against a partitioned table on MySQL 5.6.

The workaround is transferring each individual partition as if it was a standalone table. Continue reading to learn more about the detailed procedure.

Steps

1. Create the same table structure on the destination server:

[root@mysqlsandbox ~]# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.35-80.0 Percona Server (GPL), Release 80.0, Revision f113994f31

Copyright (c) 2009-2016 Percona LLC and/or its affiliates
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. …

This Log Buffer Edition covers Oracle, SQL Server and MySQL.

Oracle:

Compiling views: When the FORCE Fails You

Goldengate 12c Troubleshooting XAGENABLE

A performance Deep Dive into Tablespace Encryption

EBS Release 12 Certified with Safari 10 and MacOS Sierra 10.12

Oracle Database 12c (12.2.0.1.0) on VirtualBox

SQL Server:

…

One of the interesting features introduced in MySQL 5.7 is that innodb_buffer_pool_size is a dynamic variable (since 5.7.5, to be more specific). Yet, past experience tells us that just because a variable is dynamic, it does not make it is safe to change it on the fly.

To find out how safe this new feature is, I measured throughput on a synthetic workload (sysbench 1.0 running the oltp script) as I made changes to this variable. In this post, I will show the results that came through.

The Environment

For my tests, I used a Google Cloud Compute instance of type n1-standard-4 (that is 4 vCPUs and 15 GB of memory) with 25 GB of persistent …

MySQL Cluster is a highly available, distributed, shared-nothing database with very interesting performance characteristics for some workloads. Among other features, it supports automatic sharding and allows us to bypass the SQL layer if we don’t need it, via the NDB API (which in my eyes, makes it one of the few transactional nosql databases out there).

In this post, I’ll describe how we can set up replication from MySQL Cluster into a standalone MySQL server using Innodb as the storage engine.

Introduction

There are a few reasons to set up replication between MySQL Cluster and a non-NDB based MySQL server. These reasons include (but are not limited to): the need …