… has an issue. At Groupon, our standard MySQL database configuration follows this active/passive pattern. There …Specifically, at Groupon, our servers would be heavily I/O bound after failover as the buffer pool …All graphs looked like this (we did 39 measurements), the next graph shows chunk 4’s …
Post: Replaying database load with Percona Playback
October 25, 2012 By 9 Comments
…to upgrade or make any configuration change on your MySQL database the first advice usually is: – Benchmark! How should … query logs. With this tool you can measure how a database upgrade, change on my.cnf or schema …i_id FROM order_line WHERE ol_w_id = 1 AND ol_d_id = 10 AND ol_o_id < 3415 AND ol_o…
Post: MySQL on Amazon RDS part 1: insert performance
March 15, 2011 By 37 Comments
…Database Service (RDS) is a cloud-hosted MySQL solution. I‘ve had some clients hitting performance limitations…but as a side project, I thought it would be interesting to measure the single-threaded insert… is that there are some severe I/O slowdowns. I should have gathered more statistics and finer-…
Post: How to Identify Bad Queries in MySQL
January 10, 2011 By 16 Comments
…we’re done.” In databases, we care most about the work the database is doing. That …could be due to internal locks, I/O starvation, or what have you. …for, which has been available in MySQL for years. This is necessary … I have done it many times with simple awk scripts and various statistical measures…
Post: Finding an optimal balance of I/O, CPU, and RAM for MySQL
May 16, 2011 By 4 Comments
… the database into smaller instances and colocated them on the same machine. It’s not a new approach, but to date I’m not aware of anyone measuring the different configurations the way Vadim has done. You can read the full details in our Scaling MySQL With…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
…of an interval I used to measure the statistics on those two servers. Maybe I measured the first…I/O (including non-random I/O) is likely to be impacted. If we manage to reduce Key_reads, we might make the database…results to your IO system’s capabilities. MySQL doesn’t have good instrumentation for …
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
… on every ad, will it hamper your ability to measure the ad’s value? Is it enough to … in MySQL, you’re going to end up heavily I/O bound. Listen to any of the talks at past MySQL …Keep those big fat log files out of the database. The database is usually the most expensive and hardest-to-…
Post: Faster MySQL failover with SELECT mirroring
February 1, 2009 By 9 Comments
…I/O, etc. In reality, it can be completely unusable for a long time. To measure how much this really matters, I…is the insert buffer. Notice the pages with no database or table name — the second row in the table… doesn’t have to be the tools I used — it could be MySQL Proxy or a TCP sniffer or …
Post: MySQL File System Fragmentation Benchmarks
March 21, 2008 By 28 Comments
…i in 1 10 100 1000 10000; do ./benchmark.php $i 10000000; mysql -e’drop database test1′; mysql -e’create database test1…log_file_size=256M innodb_flush_method=O_DIRECT for Innodb. The tables were sized… The read performance, which is the main measurement for this benchmark suffered quite as expected -…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
…MySQL thread id 30898, query id 100626 localhost root Updating update iz set pad=’a’ where i…I/O ——– I/O thread 0 state: waiting for i/o request (insert buffer thread) I/O thread 1 state: waiting for i/o request (log thread) I/O…buffers 0 Database pages 258053… ratio which measures buffer pool …
