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Using Cgroups to Limit MySQL and MongoDB memory usage

Quite often, especially for benchmarks, I am trying to limit available memory for a database server (usually for MySQL, but recently for MongoDB also). This is usually needed to test database performance in scenarios with …


Worrying about the ‘InnoDB: detected cycle in LRU for buffer pool (…)’ message?

If you use Percona Server 5.5 and you have configured it to use multiple buffer pool instances than sooner or later you’ll see the following lines on the server’s error log and chances are you’ll …


Don’t worry about embedding large arrays in your MongoDB documents

In this post, I’d like to discuss some performance problems recently mentioned about MongoDB’s embedded arrays, and how TokuMX avoids these problems and delivers more consistent performance for MongoDB applications. In “Why shouldn’t I embed …


MySQL server memory usage troubleshooting tips

There are many blog posts already written on topics related to “MySQL server memory usage,” but nevertheless there are some who still get confused when troubleshooting issues associated with memory usage for MySQL. As a …


InnoDB scalability issues due to tables without primary keys

Each day there is probably work done to improve performance of the InnoDB storage engine and remove bottlenecks and scalability issues. Hence there was another one I wanted to highlight: Scalability issues due to tables …


TokuMX vs. MongoDB : In-Memory Sysbench Performance

In talking to existing MongoDB users and TokuMX evaluators, I’ve often heard that the performance of MongoDB is very good as long as your working data set fits in RAM. The story continues that if …


MySQL performance: Impact of memory allocators (Part 2)

Last time I wrote about memory allocators and how they can affect MySQL performance in general. This time I would like to explore this topic from a bit different angle: What impact does the number …


Profiling MySQL Memory Usage With Valgrind Massif

There are times where you need to know exactly how much memory the mysqld server (or any other program) is using, where (i.e. for what function) it was allocated, how it got there (a backtrace, …


Impact of memory allocators on MySQL performance

MySQL server intensively uses dynamic memory allocation so a good choice of memory allocator is quite important for the proper utilization of CPU/RAM resources. Efficient memory allocator should help to improve scalability, increase throughput and …


Review of the Tutorial on Algorithms for Memory Sensitive Computing at STOC

Martin Farach-Colton and I ran a Tutorial on Algorithms for Memory Sensitive Computing on May 18th at the 44th ACM Symposium on Theory of Computing (STOC) at NYU. Here is the program for the tutorial. Erik Demaine (MIT) spoke on the History of …