A regression was discovered after the release of MariaDB 10.1.27. It has been pulled from the downloads system, but some mirrors may still have it. Do not download or install this version. Stay with MariaDB 10.1.26 until 10.1.28 is released The MariaDB project is pleased to announce the immediate availability of MariaDB 10.1.27. See the […]
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Percona announces the release of Percona Monitoring and Management 1.3.0 on September 26, 2017.
Percona Monitoring and Management 1.3.0 introduces basic support for the MyRocks storage engine. There is a special dashboard in Metrics Monitor that presents the essential metrics of MyRocks as separate graphs. Also, Metrics Monitor graphs now feature on-demand descriptions that remain visible as long as hover over them.
For example, this graph helps you visualize MyRocks database operations of Next and Seek attributes:
There are many improvements to QAN (Query Analytics) both in the user interface design and in …
[Read more]In this blog post, we’ll look at how to avoid shared locks from subqueries.
I’m pretty sure most of you have seen an UPDATE statement matching rows returned from a SELECT query:
update ibreg set k=1 where id in (select id from ibcmp where id > 90000);
This query, when executed with
autocommit=1
, is normally harmless. However, this can have bad effects when combined with other statements in the same transaction that result in holding the shared locks from the SELECT query. But first, let me explain why the SELECT query would hold locks in the first place.
Due to InnoDB’s ACID properties, to make sure that the outer UPDATE statement has a consistent view of the matching rows from the SELECT query the server has to acquire a shared lock on those rows. No other thread should modify …
[Read more]Welcome to the first day of the Percona Live Open Source Database Conference Europe 2017: Tutorials day! Technically the first day of the conference, this day focused on provided hands-on tutorials for people interested in learning directly how to use open source tools and technologies.
Today attendees went to training sessions taught by open source database experts and got first-hand experience configuring, working with, and experimenting with various open source technologies and software.
The first full day (which includes opening keynote speakers and breakout sessions) starts Tuesday 9/26 at 9:15 am.
Some of the tutorial topics covered today were:
…
[Read more]The long awaited first release candidate of MySQL 8.0 is now available. The theme of this release is “making MySQL better for modern apps”. What does that mean exactly?
…
We are happy to invite you to the first MySQL Meetup of the MySQL UAE User Group! Please find more details below:
In my previous article about roles I said that one of the problems with role usage is that roles need to be activated before they kick in. Let's recap briefly what the problem is:
## new session, as user `root`
mysql [localhost] {root} ((none)) > create role viewer;
Query OK, 0 rows affected (0.01 sec)
mysql [localhost] {root} ((none)) > grant select on *.* to viewer;
Query OK, 0 rows affected (0.01 sec)
mysql [localhost] {root} ((none)) > create user see_it_all identified by 'msandbox';
Query OK, 0 rows affected (0.01 sec)
mysql [localhost] {root} ((none)) > grant viewer to see_it_all;
Query OK, 0 rows affected (0.01 sec)
## NEW session, as user `see_it_all`
mysql [localhost] {see_it_all} ((none)) > use test
ERROR 1044 (42000): Access denied for user 'see_it_all'@'%' to database 'test'
mysql [localhost] {see_it_all} ((none)) > show grants\G …Percona announces the release of Percona XtraDB Cluster 5.7.19-29.22 on September 22, 2017. Binaries are available from the downloads section or our software repositories.
NOTE: You can also run Docker containers from the images in the Docker Hub repository.
Percona XtraDB Cluster 5.7.19-29.22 is now the current release, based on the following:
For most people (including me until recently) database XA transactions are a fuzzy concept. In over eight years with Percona, I have never had to deal with XA transactions. Then a few weeks ago I got two customers having issues with XA transactions. That deserves a post.
XA 101
What are XA transactions? XA transactions are useful when you need to coordinate a transaction between different systems. The simplest example could be simply two storage engines within MySQL. Basically, it follows this sequence:
Once prepared, the XA transaction survives a MySQL crash. Upon restart, you’ll see something like this in the MySQL error log:
2017-08-23T14:53:54.189068Z 0 [Note] …[Read more]
Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.
Are you affected by the Ryanair flight cancellations? Have you made alternative arrangements? Have you registered for the community dinner? Even speakers have to register, so this is a separate ticket cost! There will be fun lightning talks in addition to food and drink.
You are, of course, already registered for Percona Live Europe Dublin, …
[Read more]
