Introduction

In my previous two blogs on this topic I first introduced the concept of automatic thread configuration and the thread model we use in RonDB. After receiving some questions on the topic I dived a bit deeper into explaining the RonDB thread model and its thread pipeline and compared it to another similar concept called batch pipelines.

Since then I read up a bit more on the research in this area with a focus on implementations in other key-value stores. Some researchers argue that a model where one handles the request immediately is superior to a model using a thread pipeline.

RonDB Software …

This blog introduces how RonDB handles automatic thread configuration. This blog is more technical and dives deeper under the surface of how RonDB operates. RonDB provides a configuration option, ThreadConfig, whereby the user can have full control over the assignment of threads to CPUs, how the CPU locking is to be performed and how the thread should be scheduled.

However for the absolute majority of users this is too advanced, thus the managed version of RonDB ensures that this thread configuration is based on best practices found over decades of testing. This means that every user of the managed version of RonDB will get access to a thread configuration that is optimised for their particular VM size.

In addition RonDB makes use of adaptive CPU spinning in a way that limits the power usage, but still provides very low latency in all database operations. …

If you need to automate backups, you might wonder about the different techniques available to you.

With regards to scheduling backups using built-in features of MySQL, you have two main options:

• Either run mysqldump (or mysqlbackup if you have an Enterprise licence) from an operating system scheduler, for example in Linux using "cron" or in Windows using the "Task Scheduler". This is the most commonly used option.
• Alternatively, use the Event Scheduler to perform a series of  SELECT ... INTO OUTFILE ... commands, one for each table you need to back up. This is a less commonly used option, but you might still find it useful.

Scheduling mysqlbackup with cron

mysqldump is a client program, so when you run it, you run it from a shell script, or at a terminal, rather than inside a MySQL statement. The following statement backs up the sakila …

In MySQL 5.1.33 there is a fix for an apparently innocuous bug.
Bug #36540 CREATE EVENT and ALTER EVENT statements fail with large server_id.
This is a usability bug, that makes the DBA life unnecessarily hard. The reason for having a large server_id is because a DBA might want to use the IP address as server ID, to make sure that there are unique IDs, and to have an easy way of identifying the server through the IP.
All is well until you mix the server_id assignment with event creation:

 select version();
+-----------+
| version() |
+-----------+
| 5.1.32    | 
+-----------+
1 row in set (0.00 sec)

 set global server_id =inet_aton('192.168.2.55');
Query OK, 0 rows affected (0.00 sec)

 select @@server_id;
+-------------+
| @@server_id |
+-------------+
| …

Today I was doing some work on one of our database servers (each of them has 4 SAS disks in RAID10 on an Adaptec controller) and it required huge multi-thread I/O-bound read load. Basically it was a set of parallel full-scan reads from a 300Gb compressed innodb table (yes, we use innodb plugin). Looking at the iostat I saw pretty expected results: 90-100% disk utilization and lots of read operations per second. Then I decided to play around with linux I/O schedulers and try to increase disk subsystem throughput. Here are the results: