In MySQL 8.0.16 the optimizer has improved again! Comparisons of columns of numeric types with constant values are checked and folded or removed for invalid or out-of-rage values. The goal is to speed up query execution.
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In this three-part blog series, we introduced a High Availability (HA) Framework for MySQL hosting in Part I, and discussed the details of MySQL semisynchronous replication in Part II. Now in Part III, we review how the framework handles some of the important MySQL failure scenarios and recovers to ensure high availability.
MySQL Failure Scenarios Scenario 1 – Master MySQL Goes Down
- The Corosync and Pacemaker framework detects that the master MySQL is no longer available. Pacemaker demotes the master resource and tries …
Since MySQL 5.7 one can put indexes on expressions, aka functional indexes, using generated columns. Basically you first need to use the generated column to define the functional expression, then indexed this column.
Quite useful when dealing with JSON functions, you can find an example here and the documentation there.
Starting with MySQL 8.0.13 we have now an easiest way to create functional indexes (or functional key parts as mentioned in the documentation) \o/
Let’s see how with a quick practical example.
Wondering which databases are trending in 2019? We asked hundreds of developers, engineers, software architects, dev teams, and IT leaders at DeveloperWeek to discover the current NoSQL vs. SQL usage, most popular databases, important metrics to track, and their most time-consuming database management tasks. Get the latest insights on MySQL, MongoDB, PostgreSQL, Redis, and many others to see which database management systems are most favored this year.
SQL vs. NoSQL
As any database administrator knows, the first question you have to ask yourself is whether to use a SQL or NoSQL database for your application. …[Read more]
MySQL User camp is one of the prestigious MySQL meetup happening in India for the past 6 years. Mydbops DBA’s PonSuresh and Vignesh has presented about the “JSON functions and their improvements in MySQL 8.0” at MySQL User Camp Bangalore on 13-02-2019.
JSON has been more improved a lot in MySQL 8.0 and improvements in LOB storage of MySQL boost it performance further. This presentation covers the JSON performance enhancements in MySQL 8.0 with its basic functions.
Today I'd like to continue my review of public MySQL bug reports with a
list of some bugs I've subscribed to over last 3 weeks. It's
already long enough and includes nice cases to check and share.
Note that I usually subscribe to a bug either because it directly
affects me or customers I work with, or I consider it technically
interesting (so I mostly care about InnoDB, replication,
partitioning and optimizer bugs), or it's a "metabug" - a problem in the way public bug report
is handled by Oracle engineers. These are my interests related to
As usual, I start with the oldest bugs and try to mention bug reporters by name with links to their other reports whenever this may give something useful to a reader. I try …
Percona Server for MySQL 8.0 comes with enterprise grade total data encryption features. However, there is always the question of how much overhead – or performance penalty – comes with the data decryption. As we saw in my networking performance post, SSL under high concurrency might be problematic. Is this the case for data decryption?
To measure any overhead, I will start with a simplified read-only workload, where data gets decrypted during read IO.
During query execution, the data in memory is already decrypted so there is no additional processing time. The decryption happens only for blocks that require a read from storage.
For the benchmark I will use the following workload:
sysbench …[Read more]
Want to deploy WordPress 5.0 on the Now platform by ZEIT? Our friends over at ZEIT’s Now global serverless deployment platform whipped up a great tutorial for WordPress5-on-Now using cheap MySQL hosting instances from ScaleGrid. With such strong interest in this installation, we decided to write up the steps to configure your MySQL database on the ScaleGrid side to get you up and running ever faster with WordPress on Now.
Leave your comments: https://t.co/exuBzSHkHM
◆ λ size = 13mb
◆ Just needs `wp-config.php`
◆ All static assets output directly to CDN …
The slow query log is the trusted old method of recording slow query, so the database administrator can determine which queries are in the most need for optimization. Since MySQL 5.6, it has to some extend been overshadowed by the Performance Schema which has lower overhead and thus allows collecting statistics about all queries. The slow query log has one major advantage though: the data is persisted. In MySQL 8.0.14 which was recently released, there is an improvement for the slow query log: additional statistics about the recorded queries.
The slow query log with log_slow_extra enabled.
Thanks for Facebook for …[Read more]
In a MySQL hosting replication setup, the parameter Seconds_Behind_Master (SBM), as displayed by the SHOW SLAVE STATUS command, is commonly used as an indication of the current replication lag of the slave. In this blog post, we examine how to understand and interpret this value in various situations.
Possible Values of Seconds Behind Master
The value of SBM, as explained in the MySQL documentation, depends on the state of the MySQL slave in general, and the states of MySQL slave SQL_THREAD and IO_THREAD in particular. While IO_THREAD connects with the master and reads the updates, SQL_THREAD applies these updates on the slave. Let’s examine the possible values of SBM during different states of the MySQL Slave.
When SBM Value is Null
- SBM is …
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