…, our servers would be heavily I/O bound after failover as the buffer pool pages were loaded from disk. Replaying Queries Working with…. wget -q -O – http://master_server:3307/slow | percona-playback –mysql-host 127.0.0.1 –mysql-username playback –mysql-password PaSSwOrd –mysql-schema schema…
Comment: State of the art: Galera - synchronous replication for InnoDB
April 23, 2013 By 15 Comments
… don’t see the same kind of disk i/o on it that I have seen when running mysql 5.1 or mariadb 5.5 on the same hardware in a master/slave. I wonder if it is writing as synchronous? I was able to write 100,000 queries in about 50-60 seconds to mysql…
Post: Virident vCache vs. FlashCache: Part 2
May 17, 2013 By 3 Comments
…pool. The cache devices were flushed to disk immediately prior to and immediately following each …with the default configuration, I started with a baseline HDD configuration for MySQL (configuration A, listed…data_file_path = ibdata1:100M innodb_flush_method = O_DIRECT innodb_log_buffer_size = 128M …
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
… can’t make 5h run. After 3h the disk is full, and InnoDB data size is about…file_path = ibdata1:100M:autoextend innodb_flush_method = O_DIRECT innodb_log_buffer_size = 256M innodb_flush…=/var/lib/mysql/mysql.sock user=root skip-grant-tables TokuDB-related options are all defaults, as I understand…
Post: The MySQL optimizer, the OS cache, and sequential versus random I/O
April 28, 2008 By 17 Comments
…row_length: 117 Data_length: 17217646764 Index_length: 11993816064 mysql> show table status like ‘dim1′\G *************************** 1. row *************************** Name:…is basically the difference between scanning data sequentially on disk and random disk I/O. So now you know why one join order…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
… minimize Key_reads because they are slow and cause random disk I/O. Notice that we still don’t know anything about any… assumed correlation between a Key_read and a random physical disk I/O, it is partially valid to say that we are going… and compare the results to your IO system’s capabilities. MySQL doesn’t have good instrumentation for scientifically choosing a key…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
…MySQL configurations, I didn’t try out different MySQL versions or settings. Moreover, I have been running these benchmarks for a customer so I…_method = O_DIRECT …disk RAID10 with standard 64k stripe element size makes a significant difference. When I launched the system that I was benchmarking, I…
Post: Filling the tmp partition with persistent connections
August 6, 2012 By 14 Comments
… swap, which would defeat the performance improvement as it uses disk I/O anyway. Ramfs will not swap, and also ramfs will grow… physical memory, most likely killing system in the end. Conclusion MySQL can creates temporary files even thought those temporary files are… you avoid these situations. I‘ve opened a bug report to follow this issue: http://bugs.mysql.com/bug.php?id=66237…
Post: MySQL on Amazon RDS part 1: insert performance
March 15, 2011 By 37 Comments
… Service (RDS) is a cloud-hosted MySQL solution. I‘ve had some clients hitting performance limitations … did not cross a dramatic memory-to-disk threshold, as famously happens in B-Tree inserts…intuition is that there are some severe I/O slowdowns. I should have gathered more statistics and finer-…
Post: How Percona diagnoses MySQL server stalls
March 3, 2011 By 6 Comments
… of I/O data, because sometimes the problem is that the disks are not responding within reasonable and expected tolerances, and sometimes the disks… I can use as demos, after I scrub them for sensitive details. When I finish these, I‘ll post them on Percona.TV, our MySQL… cause a stall in MySQL, and they usually begin microscopically and get worse over time, sometimes abruptly worse. I‘ll try to…
