In the “MySQL Query tuning 101” video, Alexander Rubin provides an excellent example of when to use a covered index. On slide 25, he takes the query

select name from City where CountryCode = ’USA’ and District = ’Alaska’ and population > 10000

 and adds the index

cov1(CountryCode, District, population, name)

 on table

City

. With Alex’s query tuning experience, making the right index decision is simple – but what about us mere mortals? If a query is more complicated, or simply uses more than one table, how do we know what to do? Maintaining another index …

MySQL 5.7 GA was released a couple of months ago now with 5.7.9 and 5.7.10 has been published a few days ago.  So far initial testing of these versions looks pretty good and both versions have proved to be stable. I have, however, been bitten by a couple of gotchas which if you are not … Continue reading A Couple of MySQL 5.7 gotchas to be aware of

The post A Couple of MySQL 5.7 gotchas to be aware of first appeared on Simon J Mudd's Blog.

Percona is glad to announce the first release candidate of Percona Server 5.7.10-1 on December 14, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories.

This release contains all the bug fixes from latest Percona Server 5.6 release (currently Percona Server 5.6.27-76.0).

New …

IBM POWER 8 is latest generation of the IBM POWER series, and it's a hot one. Above all, for you reading this, POWER 8 is the most Linux friendly so far and IBM really wants you to try this out. Seveal Linux distributions are supporting POWER 8 now, and MariaDB is of course the database of choise. Some cools things with the POWER 8 architecture are the support for CAPI (google for more details) and the fact that POWER 8 machines, due to a vastly superior memory architecture, can grow in memory size, which in general is good news but if you want your own POWER 8, this makes then a bit expensive (although maybe not when you consider the performance you get). IBM has fixed that recently and have announced the LC series of servers which start at $6.600 (see more here: http://www-03.ibm.com/systems/power/hardware/linux-lc.html).

So, whar about MariaDB …

Earlier in the blog series, we touched upon deployment of clustering/replication (MySQL / Galera, MySQL Replication, MongoDB & PostgreSQL), management & monitoring of your existing databases and clusters, performance monitoring and health, how to make your setup highly available through HAProxy and MaxScale, how to prepare yourself for disasters by scheduling …

In previous blog, I covered DISK/IO counters. This blog will briefly touch on Network, Threading and Contention.

Other counters:
Network I/OCOUNTER: Network Interface\Bytes Total/sec
TYPE: Instantaneous
USAGE:

#Get Instances
PS > (New-Object Diagnostics.PerformanceCounterCategory("Network Interface")).GetInstanceNames("")

Intel[R] Centrino[R] Advanced-N 6205
Microsoft Virtual WiFi Miniport Adapter _2
Microsoft Virtual WiFi Miniport Adapter
Intel[R] 82579LM Gigabit Network Connection

PS > New-Object Diagnostics.PerformanceCounter("Network Interface",
"Bytes Total/sec", "Intel[R] 82579LM Gigabit Network Connection")

CategoryName …

You may sometimes hear complaints about MySQL not providing good enough tools for profiling and execution analysis. A few years ago I would have agreed with such opinions, thankfully MySQL developers have made huge efforts to improve the situation in recent major versions. MySQL DBAs now have some great native diagnostic tools at their disposal... which is totally not what this article is about :)
Native MySQL tooling (whatever it might be) is just the tip of the iceberg and if you want to be a better troubleshooter, SysAdmins are the first people you should talk to. Their toolboxes are full of awesomeness and the tools they use have one significant advantage over MySQL tools: they can analyze server execution holistically, regardless of the MySQL version you may be using.
In this article, we will have a look at three OS-level tools: pstack, perf and callgrind (Valgrind tool).

Introduction Tools …

With Unicode it is possible for strings to look the same, but with slight differences in which codepoints are used.

For example the é in Café can be <U+0065 U+0301> or <U+00E9>.

The solution is to use Unicode normalization, which is supported in every major programming language. Both versions of Café will be normalized to use U+00E9.

In the best situation the application inserting data into the database will do the normalization, but that often not the case.

This gives the following issue: If you search for Café in the normalized form it won't return non-normalized entries.

I made a proof-of-concept parser plugin which indexes the normalized version of words.

A very short demo:

mysql> CREATE TABLE test1 (id int auto_increment primary key,
    -> txt TEXT CHARACTER SET utf8mb4, fulltext (txt));
Query OK, 0 rows affected (0.30 sec)

mysql> CREATE TABLE test2 (id int …

There was some discussion a while back to maybe make MariaDB Server follow the Ubuntu release model, i.e. having a Long Term Release (LTS) and then having a few regular fast releases with a shorter support cycle.

However its good to note that the decision now going forward is to support each and every GA release for a period of five (5) years. However, regular releases will only happen for the latest three (3) GA releases, so at this moment, you are getting updates for MariaDB Server 5.5/10.0/10.1.

Practically, we’ve not seen an update for 5.1/5.2/5.3 since 30 Jan 2013 at the time of this writing. And its clear MariaDB Server 5.5 will have an extended support policy, as it ships in Red Hat Enterprise Linux 7. 

At this time it’s worth …

MySQL Connector/Java 5.1.38 was released earlier this week, and it includes a notable improvement related to secure connections.  Here’s how the change log describes it:

When connecting to a MySQL server 5.7 instance that supports TLS, Connector/J now prefers a TLS over a plain TCP connection.

This mirrors changes made in 5.7 to the behavior of MySQL command-line clients and libmysql client library.  Coupled with the streamlined/automatic generation of TLS key material to ensure TLS availability in MySQL Server 5.7 deployments, this is an important step towards providing secure communication in default deployments.

…