The other day I was discussing new features of MySQL 5.7 with a Percona Support customer. After that conversation, I thought it would be a good idea to compile list of important features of MySQL 5.7. The latest MySQL 5.7.6 release candidate (RC) is out and is packed with nice features. Here’s a list of some MySQL 5.7 key features.

Replication Enhancements:

• One of the top features in MySQL 5.7 is multi-source replication. With multi-source replication you can point multiple master server’s to slave so limitation of slave having only one master is lift off. There is nice blog post written by my colleague on multi-source replication you will find useful.
• …

The Severalnines team is pleased to announce the release of ClusterControl 1.2.10. This release contains key new features along with performance improvements and bug fixes. We have outlined some of the key new features below. 

• Highlights of ClusterControl 1.2.10 include:
• ClusterControl DSL (Domain Specific Language) 
• Integrated Developer Studio (Developer IDE) 
• Database Advisors/JS bundle 
• On-premise Deployment of MySQL / MariaDB Galera Cluster (New implementation)
• Detection of long running and deadlocked transactions (Galera)
• Detection of most advanced (last committed) node in case of cluster failure (Galera)
• Registration of manually added nodes with ClusterControl
• Failover and Slave Promotion in MySQL 5.6 Replication setups 
• General front-end optimizations 
…

MariaDB 10.0.19 was recently released, and is available for download here:

https://downloads.mariadb.org/mariadb/10.0.19/

This is the tenth GA release of MariaDB 10.0, and 20th overall release of MariaDB 10.0.

This was a quick release in order to get a fix for a mysql_upgrade bug (MDEV-8115) introduced in 10.0.18, so there is that, and only 9 other bug fixes.

Here are the main items of note:

• Fixed the server crash caused by mysql_upgrade (MDEV-8115)
• Connect upgraded to 1.03.0007

Due to the mysql_upgrade bug fix as well as all of the fixes in MariaDB …

MariaDB 10.0.18 was recently released, and is available for download here:

https://downloads.mariadb.org/mariadb/10.0.18/

This is the ninth GA release of MariaDB 10.0, and 19th overall release of MariaDB 10.0.

There were no major functionality changes, but there were some general improvements, several security fixes, plus a 10.0.18 mysql_upgrade caution, and quite a few bug fixes, so let me cover what I feel are the main items of note:

• Security Fixes: Fixes for the following security vulnerabilities:
  • CVE-2014-8964 / CVE-2015-2325 …

MariaDB 5.5.43 was recently released (it is the latest MariaDB 5.5), and is available for download here:

https://downloads.mariadb.org/mariadb/5.5.43/

This is a maintenance release, and so there were not too many major changes, but definitely a few worth mentioning, as well as one *important* caution:

• Security Fixes: Fixes for the following security vulnerabilities:
  • CVE-2015-0501
  • CVE-2015-2571
  • …

GitHub Pages, our static site hosting service, has always had a very simple architecture. From launch up until around the beginning of 2015, the entire service ran on a single pair of machines (in active/standby configuration) with all user data stored across 8 DRBD backed partitions. Every 30 minutes, a cron job would run generating an nginx map file mapping hostnames to on-disk paths.

There were a few problems with this approach: new Pages sites did not appear until the map was regenerated (potentially up to a 30-minute wait!); cold nginx restarts would take a long time while nginx loaded the map off disk; and our storage capacity was limited by the number of SSDs we could fit in a single machine.

Despite these problems, this simple architecture worked remarkably well for us — even as Pages …

One of my favorite tools for query optimization is profiling. But recently I noticed this warning:

mysql> set profiling=1;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> show warnings;
+---------+------+----------------------------------------------------------------------+
| Level   | Code | Message                                                              |
+---------+------+----------------------------------------------------------------------+
| Warning | 1287 | '@@profiling' is deprecated and will be removed in a future release. |
+---------+------+----------------------------------------------------------------------+

After looking through certain documentation , I should indeed start using the Performance Schema to get this information.

Okay, so let’s give that a try.

I confirmed that I started MySQL 5.6.23 …

Oracle 12c introduces new catalog features including CDB_ dictionary views (which include a CON_ID column) superseding the DBA_ views that most DBA sqlplus scripts are based upon.

However, existing DBA sqlplus scripts can easily be modified using just a few simple sqlplus techniques to be compatible with 11g, as well as all types of 12c databases including legacy and container databases.

The following simple SQL and sqlplus techniques can be used to make a “universal script” that is compatible with all versions.

Illustrating the Issue

Let’s say for sake of example that we have a simple 10g/11g monitoring script that’s checking the amount of freespace in each tablespace by querying the DBA_TABLESPACE_USAGE_METRICS view.

On our 10g or 11g database the following query gives the necessary information:

SQL> select version from v$instance;

VERSION
-----------------
11.2.0.4.0

SQL> select …

This Log Buffer Edition covers various valuable blog posts from the fields of Oracle, SQL Server and MySQL.

Oracle:

• Oracle Big Data Appliance X5-2 with Big Data SQL for the DBA.
• Loading, Updating and Deleting From HBase Tables using HiveQL and Python.
• In keeping with the ODA quarterly patching strategy, Appliance Manager 12.1.2.3 is now available.
• From time to time someone publishes a query on the OTN database forum and asks how to make it go faster, and …

What is Optimizer Trace? After reading topic about Optimizer Tracer by [Morgan Tocker][1] decided to test it. From [Optimizer Trace and EXPLAIN FORMAT=JSON in 5.7][2]: Optimizer trace is a new diagnostic tool introduced in MySQL 5.6 to show how the optimizer is working internally. It is similar to EXPLAIN, with a few notable differences: It doesn’t just show the intended execution plan, it shows the alternative choices. You enable the optimizer trace, then you run the actual query. It is far more verbose in its output. For understanding goal of article please read previous one about related verified optimizer BUG: [Playing with count() optimizer work][3] ** We have 2 queries: **select count() from sales; select count(*) from sales where sales_id > 0; Firstly let’s get explain plan for query with JSON format and as regular:

       -- JSON 
          mysql> explain format=json select …