… threads IO, the test is done just after a secure erase operation on the card. The card is doing stable 380 MiB… course PCIe still provides better numbers, but the question is how much MySQL can use. In his keynote Mark Callaghan mentioned that… it is a good question how does it affect MySQL performance, and I am going to run some MySQL workloads on these cards to…
Post: Testing Samsung SSD SATA 256GB 830 - not all SSD created equal
April 25, 2012 By 10 Comments
… product, that’s why I decided to test it. For tests I use sysbench fileio, 16KiB …run You may see I gather metrics every 10 sec to see how stable the …. The results for random read case: I do not have a good explanation for … in SSD and MySQL questions – I will be giving a webinary “MySQL and SSD” on …
Comment: Emulating global transaction ID with pt-heartbeat
April 24, 2012 By 6 Comments
…mysql does not have a way match the transactions as ‘global transactions id’.I agree that matching logs is very tedious but how…information is telling that B ( relay_master_log_file: test_file , exec_master_log_pos: 2399 ) was replicating … up to the same level. that way we do not have to match the …
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
… I would like to see MySQL memory consumption plotted. I use “VSZ” columns from “ps” output on Linux. It helps me to understand how… and not): mysql> select * from information_schema.global_temporary_tables \G *************************** 1. row *************************** SESSION_ID: 7234 TABLE_SCHEMA: test TABLE_NAME: my… the best thing to do in this case is see whenever you can create isolated repeatable test cases based on your application…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… like InnoDB doing read_ahead by noticing the sequential access pattern. BKA is available in both MySQL 5…. 10; In-memory workload Now let’s see how effective are the join optimizations when the workload… the buffer that MRR uses appropriately. In my tests I noticed that with just the join_buffer_size…
Post: InnoDB's gap locks
March 27, 2012 By 14 Comments
…from t where i > 20 FOR UPDATE; +——+ | i | +——+ | 21 | | 25 | | 26 | | 30 | +——+ Phantom reads do not occur…insertion of data to other sessions. How to troubleshoot gap locks? Is …MySQL thread id 3, OS thread handle 0x7f84a78ba700, query id 163 localhost msandbox TABLE LOCK table `test…
Post: Introducing new type of benchmark
February 25, 2012 By 16 Comments
…mysql). However, like Mark Callaghan mentioned in comments, response time is way more important metric to compare. I… by Exponential distribution, with λ = M. That how it goes if to believe to the … ? – Do we need to increase number of working threads when we add nodes ? Beside cluster testing,…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… often ask us how we do a performance audit (it’s our most popular service). I thought I should write …do to just assume there’s a single instance in /var/lib/mysql and it’s reading from /etc/my.cnf. I… show the difference afterwards. Or we might have a test server to run on. It varies widely; some …
Post: How Percona strives to remain neutral and independent
March 21, 2011 By Leave a Comment
…prominent companies in the MySQL ecosystem are Percona customers, including hardware manufacturers, software …. Independence and objectivity are core Percona values. How do we balance the interests of all involved … you, but solution Y is not something I‘ve tested,” then you can either take that …
Post: A recovery trivia or how to recover from a lost ibdata1 file
June 3, 2011 By 7 Comments
… recovering by hand nearly 200 tables was not really exciting. I needed something faster and more automatic so, after reading this…_TABLENAME=`mysql -u root -B -N -e “select name from test.tables where spaceid = $CURRENT_SPACEID;”` echo “doing $CURRENT_TABLENAME $CURRENT_SPACEID” # DO WE…
