…to the tables is “const” MySQL does not count it as access to two tables. In case of “real” access to…in the query: # Time: 120911 17:31:48 # User@Host: root[root] @ localhost [] # Thread_id: 65144 Schema: sbtest Last_errno: 0 Killed… but rather helps to understand how much optimization is possible…
Post: How to debug long-running transactions in MySQL
March 8, 2011 By 6 Comments
…-digest to convert this into a query log, and examine the log. In MySQL … its thread ID. Match this up with the ID in SHOW PROCESSLIST, and look in…and I am still stumped as to how a SELECT-only transaction can …to find idle-in-transaction connections that are just sitting there doing nothing, and kill…
Post: How to Monitor MySQL with Percona's Nagios Plugins
February 22, 2012 By 11 Comments
…to monitor in MySQL. Those are only suggestions; any given deployment might want to monitor only some of them, as appropriate, and might need to…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 5 Comments
…in most cases you do not know where exactly memory is allocated. This was not much of the problem in MySQL…to max_packet_size per connection) are all connection buffers and so if you close connection MySQL can clean them up. Killing…to look at Prepared_stmt_count to see how…0 (0 + 0) Threads 425080 (…
Post: Can MySQL temporary tables be made safe for statement-based replication?
May 26, 2008 By 8 Comments
…how to make MySQL replication reliable, part of which is to eliminate …to get to the bottom of the matter. First, I stopped the slave threads so I could choose which statements to…in theory. To test my theory, I’ll shut down and restart the slave gracefully, rather than simulating a crash with kill…
Post: MySQL Backup tools used by Percona Remote DBA for MySQL
March 13, 2013 By 8 Comments
…mysqldump … -d -t How to restore mydumper data: Load the schema file Run myloader –threads=x Load … to restore data in a future blog post. Tips/Tricks: run with –kill-long-queries to …Percona XtraBackup for MySQL in parallel using all your resources available Downloading from s3 in parallel …
Post: MySQL 5.5.8 - in search of stability
January 3, 2011 By 11 Comments
…in_group = 2 innodb_read_io_threads = 16 innodb_write_io_threads = 16 innodb_purge_threads…MySQL 5.5.8 (with innodb_doublewrite enabled). In summary, my conclusion is: You can try to get stable throughput in MySQL…
Post: Getting MySQL Core file on Linux
August 26, 2011 By 1 Comment
…To check the if it works you can do kill -sigsegv `pidof mysqld` which will trigger the same code as if MySQL…this from main thread: stack_bottom = (nil) thread_stack … how you can get core files from MySQL…in many cases could be to connect as “gdb -p `pidof mysqld`” select “continue” and let MySQL…
Post: Why Swapping is bad for MySQL Performance ?
January 18, 2010 By 11 Comments
…in MySQL makes a special effort to avoid (delay) IO. If it happens to go to swap file it will more than defeat its purpose. Number of background threads…to see slowdown instead of MySQL being killed…
Post: MySQL Partitioning - can save you or kill you
December 11, 2010 By 45 Comments
… using MySQL Partitioning for Performance Optimization and I just got a relevant customer case to illustrate it. First you need to understand how partitions… (single thread) instead of IO bound. You could celebrate but hey…. you need to check the impact on master too. Master in its…
