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Java & MySQL 8.0.19

It’s the in-between term time and we’re all stuck at home. I decided to update the image for my Fedora 30 virtual machine. I had a work around to the update issue that I had encountered last October in Bug #96969 but it was not required with the current version. However, after updating from MySQL 8.0.17 to MySQL 8.0.19, I found that my Java connection example failed.

The $CLASSPATH value was correct:


The first error that I got was the my reference to MySQL JDBC driver was incorrect. The error message is quite clear:

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
Cannot connect to database server:
The server time zone …
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Evaluating Group Replication Scaling for I/O Bound Workloads

In this post, I want to evaluate Group Replication Scaling capabilities in cases when we increase the number of nodes and increase user connections. While this setup is identical to that in my post “Evaluating Group Replication Scaling Capabilities in MySQL”,  in this case, I will use an I/O bound workload.

For this test, I will deploy multi-node bare metal servers, where each node and client are dedicated to an individual server and connected between themselves by a 10Gb network.

Also, I will use 3-nodes and 5-nodes Group Replication setup. In both cases, the load is directed only to ONE node, but I expect with five nodes there is some additional overhead from replication.

Hardware specifications:

System | Supermicro; SYS-F619P2-RTN; v0123456789 (Other)
Service Tag | …
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Percona XtraBackup: Backup and Restore of a Single Table or Database

The backup and restore of a complete database is an extensive exercise. But what if you need to restore just one table which has been mistakenly modified by an incorrect query? Help is at hand with Percona XtraBackup.

For our purpose, we will take a test database having tables created by the sysbench tool. The 8.0 versions of Percona XtraBackup and Percona Server for MySQL have been used in this test.

Restore Single Table

Here we will take the backup of the sbtest2 table and restore it. The initial checksum of the table is given below:

8.0.19>CHECKSUM TABLE sbtest2;
| Table        | Checksum | …
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Use Case: Geo-distributed Multi-master MySQL for Telco Providers

This is our third ‘multi-master MySQL’ blog in our Continuent MySQL Use Case series, with a focus on Telco providers. This blog concludes our multi-master MySQL mini-series along with the following two blogs:

As per our initial multi-master MySQL use case blog, multi-master replication for MySQL typically means that a user can write to any master node knowing that the write will be eventually consistent for …

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MySQL Lock information in MySQL Shell

Last Tuesday, it was the very first session of DB AMA, Morgan Tocker made a nice presentation of MySQL Performance_Schema and illustrated it with some nice queries to get Meta et Data Locks.

As those queries were not that simple to write or at least to remember, I thought it might be a good idea to add them to MySQL Shell, the best MySQL DBA Tool !

I’ve then added a new method to the check plugin: getLocks().

Let’t see it in action:

As you can see, this is a small extension that can offers you a better view of what’s locked per transaction.

You can find several MySQL Shell Extension directly on github: …

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Finding the Unknowns in Database Audit Logs

Then secretary of Defense Donald Rumsfeld popularized the terms: “known knowns”, “known unknowns”, and “unknown unknowns.” With the ever-increasing number of data breaches and vulnerabilities, database operation teams have to account for every possibility. Visualizing your audit data allows you to look for the “unknowns”, those access patterns or connections that you’d otherwise overlook.

Although enabling an audit log and shipping it off to a vault may meet security and regulatory requirements, you will lose an important opportunity to protect your customer and employee information.

The following dashboard demonstrates the type of information that audit logs can reveal:

  • Who is connecting to my database (IP address, location, username..)
  • Who is trying to connect to my database but getting access errors?
  • Which tables are being accessed and by whom?
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MySQL without the SQL

MySQL can be used as a NoSQL JSON Document Store as well as a traditional relational database.  Before the MySQL Document Store you needed a DBA, or someone acting as one, to set up the schema to hold the tables and the tables according to how the data was arranged (and the indexes, constraints, and all the other stuff RDMS are known for). This was great for cases when you know exactly what the data looks likes, there are no changes to the structure of that data, and once things are set they go one that way forever.

But what about projects where change is constant, or where making changes to accommodate but keeping the old stuff as already formatted is needed? That is a perfect case for the MySQL Document Store.

MySQL w/o SQLSo you can connect to the server, create a schema, create a document collection, and store data without once using SQL. 

This video shows you a simple example of …

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Still have binlog_error_action as IGNORE_ERROR?

Recently, we were affected by an ignored configuration option introduced in MySQL 5.6. This incident caused us to perform extended planning of downtime and the rebuilding of the slave. In this post, we’ll discuss our encounter with binlog_error_action and likely bad default.

The incident started with an alert from our monitoring platform that a check failed to verify a MySQL master’s binary log coordinates. My colleague working from the other side of the globe observed the following:

mysql> show master status;
Empty set (0.00 sec)

mysql> show binary logs;
ERROR 1381 (HY000): You are not using binary logging

Interestingly, the MySQL slave was still reporting that everything was okay!

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: master
                  Master_User: …
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Evaluating Group Replication with Multiple Writers in MySQL

In this blog, I want to evaluate Group Replication Scaling capabilities to handle several writers, that is, when the read-write connection is established to multiple nodes, and in this case, two nodes. This setup is identical to my previous post, Evaluating Group Replication Scaling Capabilities in MySQL.

For this test, I deploy multi-node bare metal servers, where each node and client are dedicated to an individual server and connected between themselves by a 10Gb network.

I use the 3-nodes Group Replication setup.

Hardware specifications:

System | Supermicro; SYS-F619P2-RTN; v0123456789 (Other)
Service Tag | S292592X0110239C
   Platform | Linux
    Release | Ubuntu 18.04.4 LTS (bionic)
     Kernel | 5.3.0-42-generic
Architecture | CPU = 64-bit, OS = 64-bit
  Threading | NPTL 2.27 …
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Daylight Saving Time and System Time Zone in MySQL

March is not only the month when a pandemic closed all borders and people had to stay home on the quarantine; it’s also the month when daylight saving time change happens. For some regions, this is not only a time change but also a switch to a different timezone. For example, New York uses EST during winter and EDT during summer. If you use the system timezone and do not restart the MySQL server or a PXC node after the switch, you may notice that the change was not implemented.

You may end up with a situation where some of your cluster nodes still use the time zone before the switch (e.g. EST) and others use the timezone after the change (e.g. EDT).

$ date
Sun Mar  8 03:03:28 EDT 2020

$ ./bin/mysql  -h127.0.0.1 -P3373 -uroot test
EDT node> show variables like '%zone%'; …
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