… of the very frequent cases with performance problems with MySQL is what they happen every so often or certain times. Investigating them we find out what the cause is some batch jobs, reports and other non response time critical… good idea. It also often helps with monopolizing replication thread. For example if I need to delete old data instead of…
Post: New distribution of random generator for sysbench - Zipf
May 9, 2012 By 3 Comments
… to test cache, but it is hard to emulate high IO load. That’s why I was looking for alternatives, and Zipfian distribution seems decent one. This distribution has a parameter θ (theta), which defines how skewed the distribution is… getting uniform distribution – each row is accessed equal times ( for row X: 1/(X^0) ). There is a research that shows that user…
Post: Testing Samsung SSD SATA 256GB 830 - not all SSD created equal
April 25, 2012 By 10 Comments
… are looking for cheaper alternatives. SATA SSD is an options. There is many products based on MLC technology, and Intel 320 I would say is… I am looking for comparable alternatives. Samsung 830 256GB looked like a good product, that’s why I decided to test it. For tests… IO library to get time metrics for particular IO block. so my testing command line looks like: sysbench –test=fileio –file-total…
Comment: Testing Samsung SSD SATA 256GB 830 - not all SSD created equal
April 25, 2012 By 10 Comments
… to stall reads for so long because of garbage collection. Vadim – did you look at Intel 520 drives ? These look like a lot higher performance than 320 model yet they are reasonably comfortable. Here is…
Comment: Benchmarking single-row insert performance on Amazon EC2
May 16, 2012 By 11 Comments
… isn’t measuring the cost of index maintenance. Transaction-id is auto-incremented, and so partitioning on transaction-id makes the… higher with this partitioning, however since you’ll have to look in each of the ten partitions to query one of… a good challenge. The URL for iibench is slightly incorrect. The correct URL for version you used is http://tokutek.com/downloads/iiBench-1…
Post: Benchmarking single-row insert performance on Amazon EC2
May 16, 2012 By 11 Comments
… row insert challenge” for which this tool was originally built is long over, but still the tool serves well for benchmark purposes. OK… reduced to ~9k INSERTs Per Second. Let’s take a look at the graphs have a better view of the whole… on read performance and hence having secondary indexes is an obvious choice. But for those applications that are write mostly or that…
Post: Testing STEC SSD MACH16 200GB SLC
April 25, 2012 By 7 Comments
… block size (to match workload from InnoDB, as this is primary usage for me), and recently I switched to use async IO… IO library to get time metrics for particular IO block. so my testing command line looks like: sysbench –test=fileio –file-total… the webinar. Disclaimer: This benchmark is done as part of consulting work for STEC, but this post is totally independent and fully reflects…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
… connection variables is how you can test it, though it does not cover everything. For prepared statements you might want to look at… restrict memory usage. For Permanent tables it is easy. We can look at information_schema to see how much memory is being used by… this is often one of the first things I do as it is least intrusive. Run SHOW ENGINE INNODB STATUS and look for memory…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
… preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a look at….5 Now let’s take a look briefly at what this enhancement actually is, and what is it aimed at. Index Condition Pushdown… after the part on which range condition is applied cannot be used for filtering records. For example, suppose you have a key defined…
Comment: ext4 vs xfs on SSD
April 24, 2012 By 23 Comments
…. Take a look at the bug list Red Hat at ant one point — the list is quite long. For that matter look at the bug list or patch list for MySQL/InnoDB at any one…, and to the uninitiated it will look frightening. The same is true for commercial software, if the list is known. With commercial software and…
