We saw yesterday that when an issue (like network splitting), it’s possible to remain with a partitioned cluster where none of the partition have quorum (majority of members). For more info read how to manage a split-brain situation.

If your read the previous article you notice the red warning about forcing the quorum. As an advice is never too much, let me write it down again here : “Be careful that the best practice is to shutdown the other nodes to avoid any kind of conflicts if they reappear during the process of forcing quorum“.

But if some network problem is happening it might not be possible to shutdown those other nodes. Would it be really bad ?

YES !

Split-Brain

Remember, we were in this situation:

We …

Everywhere I go to present MySQL InnoDB Cluster, during the demo of creating a cluster, many people doesn’t understand why when I’ve 2 members, my cluster is not yet tolerant to any failure.

Indeed when you create a MySQL InnoDB Cluster, as soon as you have added your second instance, you can see in the status:

    "status": "OK_NO_TOLERANCE",      
    "statusText": "Cluster is NOT tolerant to any failures.",

Quorum

Why is that ? It’s because, to be part of primary partition (the partition that holds the service, the one having a Primary-Master in Single Primary Mode, the default mode), your partition must reach the majority of nodes (quorum). In MySQL InnoDB Cluster (and many other cluster solutions), to achieve quorum, the amount of members in a partition must be > (bigger) than 50%.

So when we have 2 nodes, if there is a network issue between the …

Please join Percona’s Bug Analyst, Lalit Choudhary as he presents his talk MySQL 8.0 Architecture and Enhancement on Tuesday, April 9th, 2019 at 6:00 AM PDT (UTC-7) / 9:00 AM EDT (UTC-4).

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The release of MySQL 8.0 offers much more to users compared to previous releases. There are major changes in architecture as well as adding differentiating features, and improvements to manage the database more efficiently.

In our talk we will go through, MySQL 8.0 …

The last blog entry was very popular and there were lots of requests for some introductory information on the spatial data types. 

Well Known Text Or Binary
I am going to use the GEOMETRY data type over POINT, LINESTRING, or POLYGON as it can store any of those three while the other three can only contain data matching their name (so POINT can holds only point data, etc.). The values are stored in an internal geometry format but it takes wither WKT or WKB formatted data.

Those are Well-Known Text (WKT) or Well-Known Binary (WKB) formats repectively. I am hoping most of your are better with text than binary so the following examples demonstrate how to insert geometry values into a table by converting WKT values to internal geometry format.

So let us start with a …

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When you write stored procedures in MySQL, you sometimes need to generate queries on the fly, for example as you process the result of another query. This is supported using prepared statements. This blog explores how you can take advantage of the sys schema to simplify the use of dynamic queries.

Executing a query using the sys.execute_prepared_stmt() procedure.

The sys schema includes several stored procedures and functions as well as views to make the database administrator’s life easier. One of these is the …

MySQL before version 5.7 had less than stellar Geographic Information Systems (GIS) support.  In version 5.7 the Boost.Geometry two dimensional or 2D libraries were added.  And with 8.0 came the three dimensional or 3D libraries. But how do you use these features?

I would like to state up front that this is all new to me and this is an attempt for me to document what it takes to go from zero knowledge on GIS to something hopefully better.  What I want to do as an exercise is to get the distance between two places from their longitude and latitude, say two cities near where I live.  So what do we have to do to accomplish that?

It is actually easy with the functions provided if we have the longitude and latitude in an SRID 4326 format.

SELECT ST_Distance(
 (SELECT loc FROM cities WHERE name = 'Trondheim'),
 (SELECT loc FROM cities WHERE …

Why migrating to MySQL 8.0 ?

MySQL 8.0 brings a lot of new features. These features make MySQL database much more secure (like new authentication, secure password policies and management, …) and fault tolerant (new data dictionary), more powerful (new redo log design, less contention, extreme scale out of InnoDB, …), better operation management (SQL Roles, instant add columns), many (but really many!) replication enhancements and native group replication… and finally many cool stuff like the new Document Store, the new MySQL Shell and MySQL InnoDB Cluster that you should already know if you follow this blog (see these TOP 10 for features for developers and this TOP 10 for DBAs & OPS).

Not anymore a drop in replacement !

We …

On this article, I will show you how to migrate your wordpress database from the MariaDB on CentOS to the real MySQL.

Why migrating to MySQL 8.0 ?

MySQL 8.0 brings a lot of new features. These features make MySQL database much more secure (like new authentication, secure password policies and management, …) and fault tolerant (new data dictionary), more powerful (new redo log design, less contention, extreme scale out of InnoDB, …), better operation management (SQL Roles, instant add columns), many (but really many!) replication enhancements and native group replication… and finally many cool stuff like the new Document Store, the new MySQL Shell and MySQL InnoDB Cluster that you should already know if you follow this …

Please join Percona’s Principal Support Engineer, Sveta Smirnova, as she presents MySQL Performance Schema in 1 hour on Thursday, March 21st, 2019, at 10:00 am PDT (UTC-7) / 1:00 pm EDT (UTC-4).

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MySQL 8.0 Performance Schema is a mature tool, used by humans and monitoring products. It was born in 2010 as “a feature for monitoring server execution at a low level.” The tool has grown over the years with performance fixes and DBA-faced features. In this webinar, I will give …

Consistency during reads have been a small concern from the adopters of MySQL InnoDB Cluster (see this post and this one).

This is why MySQL supports now (since 8.0.14) a new consistency model to avoid such situation when needed.

Nuno Carvalho and Aníbal Pinto already posted a blog series I highly encourage you to read:

• Group Replication – Consistency Levels
• Group Replication: Preventing stale reads on …