Tag: sys schema

Feed: MariaDB Knowledge Base Article Feed. Author: . The sys_config table holds configuration options for the sys schema. This is a persistent table (using the InnoDB storage engine), with the configuration persisting across upgrades (new options are added with INSERT IGNORE). The table also has two related triggers, which maintain the user that INSERTs or UPDATEs the configuration - sys_config_insert_set_user and sys_config_update_set_user respectively. Its structure is as follows: +----------+--------------+------+-----+-------------------+-----------------------------+ | Field | Type | Null | Key | Default | Extra | +----------+--------------+------+-----+-------------------+-----------------------------+ | variable | varchar(128) | NO | PRI | NULL | | | value | varchar(128) | ... Read More

Feed: Planet MySQL; Author: Dave Stokes;  Is MySQL going invisible?  Invisible Indexes were included in MySQL 8.0 and now with version 8.0.23 we have Invisible Columns.Indexes You Can Not See!The value of the invisible index is that it allows you to make an index disappear from the view of the optimizer.  In the distant days before 8.0, you would often delete an index you were pretty much definitively positive nobody or no query was using.  And then you would find out that yes, not only was that index you just deleted necessary to everyone in the galaxy (but maybe you)  ... Read More

Feed: Planet MySQL; Author: MySQL Performance Blog; Understanding how MySQL uses memory is key to tuning it for optimal performance as well as troubleshooting cases of unexpected memory usage, i.e. when you have MySQL Server using a lot more than you would expect based on your configuration settings.Early in MySQL history, understanding memory usage details was hard and included a lot of guesswork.  Is it possible that some queries running require a large temporary table or allocated a lot of memory for stored user variables?  Are any stored procedures taking an unexpectedly high amount of memory? All could be reasons ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . There are several ways to move data between SQL Server and MariaDB. Here we will discuss them and we will highlight some caveats. Moving Data Definition from SQL Server to MariaDB To copy an SQL Server data structures to MariaDB, one has to: Generate a CSV file from SQL Server data. Modify the syntax so that it works in MariaDB. Run the file in MariaDB. Variables That Affect DDL Statements DDL statements are affected by some server system variables. sql_mode determines the behavior of some SQL statements and expressions, including how strict ... Read More

Feed: Planet MySQL; Author: Marco Tusa; What you may not know about random number generation in sysbenchSysbench is a well known and largely used tool to perform benchmarking. Originally written by Peter Zaitsev in early 2000, it has become a de facto standard when performing testing and benchmarking. Nowadays it is maintained by Alexey Kopytov and can be found in Github at https://github.com/akopytov/sysbench. What I have noticed though, is that while widely-used, some aspects of sysbench are not really familiar to many. For instance, the easy way to expand/modify the MySQL tests is using the lua extension, or the embedded ... Read More

Feed: Planet MySQL; Author: Jesper Krogh; I have over the last few years been fortunate to have two books published through Apress, Pro MySQL NDB Cluster which I wrote together with Mikiya Okuno and MySQL Connector/Python Revealed. With the release of MySQL 8 around a year ago, I started to think of how many changes there has been in the last few MySQL versions. Since MySQL 5.6 was released as GA in early 2013, some of the major features related to performance tuning includes the Performance Schema which was greatly changed in 5.6, histograms, EXPLAIN ANALYZE, hash joins, and visual ... Read More

Feed: Planet MySQL; Author: Severalnines; One of the key factors of a performant MySQL database server is having good memory allocation and utilization, especially when running it in a production environment. But how can you determine if the MySQL utilization is optimized? Is it reasonable to have high memory utilization or does it require fine tuning? What if I come up against a memory leak? Let's cover these topics and show the things you can check in MySQL to determine traces of high memory utilization. Memory Allocation in MySQL Before we delve into the specific subject title, I'll just give ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . There are several ways to move data from SQL Server to MariaDB. There are also some caveats. Moving Data Definition from SQL Server to MariaDB To copy an SQL Server data structures to MariaDB, one has to: Generate a file containing the SQL commands to recreate the database. Modify the syntax so that it works in MariaDB. Run the file in MariaDB. Variables That Affect DDL Statements DDL statements are affected by some server system variables. sql_mode determines the behavior of some SQL statements and expressions, including how strict error checking is, ... Read More

Feed: Planet MySQL; Author: Severalnines; April 2018 is not just a date for the MySQL world. MySQL 8.0 was released there, and more than 1 year after, it’s probably time to consider migrating to this new version. MySQL 8.0 has important performance and security improvements, and, as in all migration to a new database version, there are several things to take into account before going into production to avoid hard issues like data loss, excessive downtime, or even a rollback during the migration task. In this blog, we’ll mention some of the new MySQL 8.0 features, some deprecated stuff, and ... Read More

Feed: Planet MySQL; Author: Geir Hoydalsvik; The MySQL Development team is very happy to announce that MySQL 8.0.19 is now available for download at dev.mysql.com. In addition to bug fixes there are a few new features added in this release.  Please download 8.0.19 from dev.mysql.com or from the MySQL  Yum,  APT, or SUSE repositories. The source code is available at GitHub. You can find the full list of changes and bug fixes in the 8.0.19 Release Notes. Here are the highlights. Enjoy! InnoDB ReplicaSet Following InnoDB Cluster as our first, fully integrated MySQL HA solution based on Group Replication, InnoDB ... Read More