We were using memcache in our application for a long time and it helped a lot to reduce DB servers load on some huge queries. But there was a problem (sometimes called a “dog-pile effect”) - when some cached value was expired and we had a huge traffic, sometimes too many threads in our application were trying to calculate new value to cache it.

For example, if you have some simple but really bad query like

SELECT COUNT(*) FROM some_table WHERE some_flag = X

which could be really slow on a huge tables, and your cache expires, then ALL your clients calling a page with this counter will end up waiting for this counter to be updated. Sometimes there could be tens or even hundreds of such a queries running on your DB killing your server and breaking an entire application (number of …

You have to love error messages some times. Today in MySQL is was “ERROR 1289 (HY000): The ‘UNKNOWN’ feature is disabled;”

What was even more interesting is the error message and indeed the error number changed across different versions. I took the time to also review the error in the current versions of 5.0, 5.1 and 6.0.

5.0.37/5.0.51a - ERROR 1289 (HY000): The ‘InnoDB’ feature is disabled; you need MySQL built with ‘InnoDB’ to have it working
5.1.19/5.1.23/6.0.4 - ERROR 1286 (42000): Unknown table engine ‘InnoDB’
6.0.0 - ERROR 1289 (HY000): The ‘UNKNOWN’ feature is disabled; you need MySQL built with ‘UNKNOWN’ to have it working

You can read more at Bug #29373

In my previous post I briefly mentioned Database Appliance with Project Indiana. Now that Sun has acquired MySQL (or as some people say MySQL has acquired Sun) and with our existing work in progress with PostgreSQL, there are quite a bit of options available of using some combination  of Storage, System, Operating System, Database  along with some end user application and present it as either Database Appliance or use it as Embedded Database. 

I thought I will just discuss the audience, symptoms, merits, cons etc regarding the two approach and how they can be useful. 

 The first question is who likes database appliances and who wants embedded database? To answer that I would put the question back: What do you in hand? A hammer or a screw-driver? Because if you have a hammer, the whole world is a nail to you and …

One thing that sometimes bugs me in MySQL is the huge amount of errata. The database is packed with features and abilities that are side-effects from "historical decisions". Decisions that were made when it wasn't planned to be an enterprise product, or changes made to ease porting applications to MySQL from other databases. Legacy, so to speak.

The timestamp data type is a good example - the timestamp manual section is a long list of exceptions and special cases. I usually re-read the manual page before using it. Another good example is the amount of date and time functions that exist in MySQL. There are way too many of them, some overlapping in function, and some just exist as aliases to other functions for compatibility. Just go over the list.

On …

In this blog I'm sharing the results of a series of tests designed to explore the impact of various MySQL and, in particular, InnoDB tunables. Performance engineers from Sun have previously blogged on this subject - the main difference in this case is that these latest tests were based on Linux rather than Solaris.

It's worth noting that MySQL throughput doesn't scale linearly as you add large numbers of CPUs. This hasn't been a big issue to most users, since there are ways of deploying MySQL successfully on systems with only modest CPU counts. Technologies that are readily available and widely deployed include replication, which allows horizontal scale-out using query slaves, and memcached, which is very effective at reducing the load on a MySQL server. That said, scalability is likely to become more important as people increasingly deploy systems with quad-core processors, with the result that even two processor systems will need to …

In this blog I'm sharing the results of a series of tests designed to explore the impact of various MySQL and, in particular, InnoDB tunables. Performance engineers from Sun have previously blogged on this subject - the main difference in this case is that these latest tests were based on Linux rather than Solaris.

It's worth noting that MySQL throughput doesn't scale linearly as you add large numbers of CPUs. This hasn't been a big issue to most users, since there are ways of deploying MySQL successfully on systems with only modest CPU counts. Technologies that are readily available and widely deployed include replication, which allows horizontal scale-out using query slaves, and memcached, which is very effective at reducing the load on a MySQL server. That said, scalability is likely to become more important as people increasingly deploy systems with quad-core processors, with the result that even two processor systems will need to …

In this blog I'm sharing the results of a series of tests designed to explore the impact of various MySQL and, in particular, InnoDB tunables. Performance engineers from Sun have previously blogged on this subject - the main difference in this case is that these latest tests were based on Linux rather than Solaris.

It's worth noting that MySQL throughput doesn't scale linearly as you add large numbers of CPUs. This hasn't been a big issue to most users, since there are ways of deploying MySQL successfully on systems with only modest CPU counts. Technologies that are readily available and widely deployed include replication, which allows horizontal scale-out using query slaves, and memcached, which is very effective at reducing the load on a MySQL server. That said, scalability is likely to become more important as people increasingly deploy systems with quad-core processors, with the result that even two processor systems will need to …

Recently we put together a consolidation benchmark to see how an open-source stack performs against the proprietary stack from Microsoft. Solaris, MySQL, and Sun Web Server running on the open-source UltraSPARC T2 processor were pitted against a Microsoft SW stack running on a 4-socket QC Xeon server. This benchmark highlights the continued trend to incorporate MySQL open-source databases and how it works under virtualization (Solaris Zones).

The Sun SPARC Enterprise T5220 (1.4 Ghz UltraSPARC T2 processor) and Solaris Containers managing a consolidation of Open-Source Software components (MySQL Database and Sun Java System Web Server) provided 2.4 times better performance than the HP DL580 system (four Xeon quad-core processors) and a major virtualization software, Microsoft Windows 2003 Server EE, Microsoft SQLserver database and Microsoft IIS webserver.

The Sun SPARC Enterprise T5220 using the MySQL database in Solaris zones is …

Recently we put together a consolidation benchmark to see how an open-source stack performs against the proprietary stack from Microsoft. Solaris, MySQL, and Sun Web Server running on the open-source UltraSPARC T2 processor were pitted against a Microsoft SW stack running on a 4-socket QC Xeon server. This benchmark highlights the continued trend to incorporate MySQL open-source databases and how it works under virtualization (Solaris Zones).

The Sun SPARC Enterprise T5220 (1.4 Ghz UltraSPARC T2 processor) and Solaris Containers managing a consolidation of Open-Source Software components (MySQL Database and Sun Java System Web Server) provided 2.4 times better performance than the HP DL580 system (four Xeon quad-core processors) and a major virtualization software, Microsoft Windows 2003 Server EE, Microsoft SQLserver database and Microsoft IIS webserver.

The Sun SPARC Enterprise T5220 using the MySQL database in Solaris zones is …

Recently we put together a consolidation benchmark to see how an open-source stack performs against the proprietary stack from Microsoft. Solaris, MySQL, and Sun Web Server running on the open-source UltraSPARC T2 processor were pitted against a Microsoft SW stack running on a 4-socket QC Xeon server. This benchmark highlights the continued trend to incorporate MySQL open-source databases and how it works under virtualization (Solaris Zones).

The Sun SPARC Enterprise T5220 (1.4 Ghz UltraSPARC T2 processor) and Solaris Containers managing a consolidation of Open-Source Software components (MySQL Database and Sun Java System Web Server) provided 2.4 times better performance than the HP DL580 system (four Xeon quad-core processors) and a major virtualization software, Microsoft Windows 2003 Server EE, Microsoft SQLserver database and Microsoft IIS webserver.

The Sun SPARC Enterprise T5220 using the MySQL database in Solaris zones is …