mysql> select @@old_passwords;[Read more...]
| @@old_passwords |
| 0 |
1 row in set (0.00 sec)
mysql> set old_passwords=1;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> show warnings;
| Level | Code | Message |
This year’s MySQL Central at Oracle Open World was an exhilarating experience. In contrast to the previous year’s MySQL Connect events, MySQL have now got their own Central at the main Oracle Open World. In the previous years, we were always short on time and trying to get a lot of sessions into just two days was just to much. This time I could both present sessions, attend sessions by other users, and also to talk to people in the MySQL community: something that I really enjoy and also find very valuable to see where we should be heading.
This year, the “MySQL Fabric Team” representation on MySQL Central was me and Narayanan Venkateswaran, which is heading the sharding solution in MySQL Fabric. Together with the conference, we also released MySQL Fabric 1.5.2 as the GA release of MySQL Fabric 1.5 containing[Read more...]
For some reason, we’ve been getting a lot of issues with ORDER BY optimization recently. The fixes have passed Elena Stepanova’s scrutiny and I’ve pushed them to MariaDB 10.1. Now, MariaDB’s
ORDER BY ... LIMIT optimizer:
MariaDB 5.5.40 was recently released (it is the latest MariaDB 5.5), and is available for download here:
This is a maintenance release, and so there are not too many big changes of note, just a number of normal bug fixes. However, there are a few items worth mentioning:
MariaDB 5.5 and then MySQL 5.6 got Index Condition Pushdown (ICP) optimization (initially coded by yours truly). The idea of ICP is simple: after reading the index record, check the part of WHERE condition that can be computed using index columns, and only then read the table record. That way, we avoid reading table rows that don’t satisfy index condition:
It seems apparent that ICP can never make things slower. The WHERE clause has to be checked anyway, and not reading certain records can only make things faster.
That was what I thought, too, until recently Joffrey Michaie observed the contrary “in the wild”: we’ve got a real-world case where[Read more...]
In a previous blog post (Importing related MySQL tables into an Excel Data Model using MySQL for Excel) we covered in detail how an Excel Data Model can be created containing tables and their relationships so the data can be analyzed in Excel via a PivotTable. In this blog post we are going to talk about one of the features included since MySQL for Excel 1.3.0 that allows you to create PivotTables for data imported from MySQL tables, views or stored procedures, or more importantly for the whole Excel Data Model if it is created.
MySQL has information_schema.tables that contain information such as “data_length” or “avg_row_length.” Documentation on this table however is quite poor, making an assumption that those fields are self explanatory – they are not when it comes to tables that employ compression. And this is where inconsistency is born. Lets take a look at the same table containing some highly compressible data using different storage engines that support MySQL compression:
mysql> select * from information_schema.tables where table_schema='test' G *************************** 1. row *************************** TABLE_CATALOG: def TABLE_SCHEMA: test TABLE_NAME: comp TABLE_TYPE: BASE TABLE ENGINE: TokuDB VERSION: 10[Read more...]
Installing MariaDB became very easy on the latest CentOS /RHEL Linux version 7. During initial setup MariaDB has a tick in the graphical setup environment which enables MariaDB and replaces MySQL.
During installation the section
allows enabling a MariaDB server.
If you prefer the command line the installation can be performed with:
shell> yum install mariadb-server
MariaDB is shipped untuned and not protected with MariaDB version 5.5.35. No basic optimizations in the configuration file have been set and the root user has no password. An update will install the[Read more...]