High availability is necessary for organizations to compete. This blog post shows the tools for for MySQL databases and how we can help configure and deploy.

The post The Mechanics of High Availability appeared first on Datavail.

Running out of disk space is something which, of course, should never happen as we all setup monitoring and alerting and only run well behaved applications. But when it does happen we want things to fail gracefully.

So what happens when mysqld runs out of disk space?
The answer is: It depends

1. It might start to wait until disk space becomes available.
2. It might crash intentionally after a 'long semaphore wait'
3. It might return an error to the client (e.g. 'table full')
4. It might skip writing to the binlog (see binlog_error_action )

What actually happens might depend on the filesystem and OS.

Fixing the disk space issue can be done by adding more space or cleaning up some space. The later can often be …

I made some improvements to the 'proxy' inside of MySQL 5.7 that I've created for WarpSQL (Shard-Query 3).  I've made the MySQL proxy/shim pluggable and I moved the SQLClient to sql/sql_client.cc.  I've merged these changes into 'master' in my fork.

Now you can create "SQL shim" plugins (SHOW PASSWORD is implemented in plugin/sql_shim) and install them in the server like regular plugins:

-- command doesn't work
mysql> show password;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'password' at line 1

-- install the example sql_shim plugin:
mysql> install plugin sql_shim soname 'sql_shim.so';                                                                 Query OK, 0 rows affected (0.00 sec)

-- now the command works
mysql> show password;
+--+
|  |
+--+
|  |
+--+
1 row in set (0.00 sec)

…

I made some improvements to the 'proxy' inside of MySQL 5.7 that I've created for WarpSQL (Shard-Query 3).  I've made the MySQL proxy/shim pluggable and I moved the SQLClient to sql/sql_client.cc.  I've merged these changes into 'master' in my fork.

Now you can create "SQL shim" plugins (SHOW PASSWORD is implemented in plugin/sql_shim) and install them in the server like regular plugins:

-- command doesn't work
mysql> show password;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'password' at line 1

-- install the example sql_shim plugin:
mysql> install plugin sql_shim soname 'sql_shim.so';                                                                 Query OK, 0 rows affected (0.00 sec)

-- now the command works
mysql> show password;
+--+
|  |
+--+
|  |
+--+
1 row in set (0.00 sec)

…

[this is a repost of my http://shardquery.com blog post, because it did not syndicate to planet.mysql.com]

As work on WarpSQL (Shard-Query 3) progresses, it has outgrown MySQL proxy.  MySQL proxy is a very useful tool, but it requires LUA scripting, and it is an external daemon that needs to be maintained.  The MySQL proxy module for Shard-Query works well, but to make WarpSQL into a real distributed transaction coordinator, moving the proxy logic inside of the server makes more sense.

The main benefit of MySQL proxy is that it allows a script to "inject" queries between the client and server, intercepting the results and possibly sending back new results to the client.  I would like similar functionality, but inside of the server.

For example, I would like to implement new SHOW commands, and these commands do not need to be …

[this is a repost of my http://shardquery.com blog post, because it did not syndicate to planet.mysql.com]

As work on WarpSQL (Shard-Query 3) progresses, it has outgrown MySQL proxy.  MySQL proxy is a very useful tool, but it requires LUA scripting, and it is an external daemon that needs to be maintained.  The MySQL proxy module for Shard-Query works well, but to make WarpSQL into a real distributed transaction coordinator, moving the proxy logic inside of the server makes more sense.

The main benefit of MySQL proxy is that it allows a script to "inject" queries between the client and server, intercepting the results and possibly sending back new results to the client.  I would like similar functionality, but inside of the server.

For example, I would like to implement new SHOW commands, and these commands do not need to be …

Several months ago I reported on Default Users in MySQL 5.7. With the addition of the sys schema the server needs an extra user to secure operations. The problem with extra users is that, if you are not aware of their existence and why they are needed, you may easily mismanage them. For example, you may have a cleanup routine that you run when you use a new server, and the routine may have a command like

DELETE FROM mysql.user WHERE user != 'root';

This was good up to MySQL 5.6. Then the sys schema was added, and with it the user mysql.sys, which may cause errors if you try to re-create views in the sys schema.

The latest user sneaking below the radar is mysqlxsys. Like its predecessor, it …

MySQL Sandbox 3.1.07 adds several options to execute shell or SQL commands during the sandbox installation.

Figure 1: MySQL Sandbox states and where you can run the hooks

There are 3 options to run shell commands, 2 to run SQL queries, and 2 to run SQL files.

## Shell commands
--pre_start_exec=command  : runs 'command' after the installation, before the server starts
--pre_grants_exec=command : runs 'command' after the server starts, before loading the grants.
--post_grants_exec=command : runs 'command' after the loading the grants.

## SQL statements
--pre_grants_sql=query : runs 'query' before loading the grants.
--pre_grants_file=filename : runs SQL file 'filename' before loading the grants.
--post_grants_sql=query : runs 'query' …

This is not a comprehensive review, nor an user guide. It's a step-by-step account of my initial impressions while trying the new MySQL XProtocol and the document store capabilities. In fact, I am barely scratching the surface here: more articles will come as time allows.

MySQL 5.7 has been GA for several months, as it was released in October 2015. Among the many features and improvements, I was surprised to see the MySQL team emphasizing the JSON data type. While it is an interesting feature per se, I failed to see the reason why so many articles and conference talks were focused around this single feature. Everything became clear when, with the release of MySQL 5.7.12, the MySQL team announced a new release model.

Overview

In …

Excerpt from http://paper-leaf.com/alton-jquery-scroll-jacking-plugin/
"Scrolljacking basically means we replace native scrolling (what you’re used to) with targeted scrolling: when the user initiates a scroll, either with their mouse or keyboard, scrolljacking takes them to an exact vertical point on the screen (for example, the top of the next content container). When done properly, scrolljacking can be a part of a unique, enjoyable online experience."The above definition makes it quite clear what scrolljacking is.

Excerpt from http://www.sitepoint.com/scrolljacking-accessibility/
"Recently, Apple came up with the new concept of ‘scrolljacking’ in their product pages. This is method that ‘re-wires’ the behavior your browser’s …