…are cases when MySQL will allocate a lot of memory for table cache, especially if you’re using large blobs. It is easy to check…are allocated (and how much memory they use). Memory Tables MEMORY tables can take memory. There are implicit MEMORY tables which are allocated for query…
Post: MySQL Slow query log in the table
May 31, 2007 By Leave a Comment
…MySQL 5.1 get MySQL slow query log logged in mysql.slow_log…be blocked as normal DELETE statements are blocked. More than that. I found even if I convert table to MyISAM, disable concurrent inserts and run long reporting query on the log file query execution is still proceeds. I have not checked if…
Post: How to use tcpdump on very busy hosts
April 18, 2011 By 17 Comments
…are getting even 5% of tcpdump packets dropped by the kernel, the results can be skewed enough to cause confusion about which queries are really slow…to the host’s slow-query-log (for example, none of the top 5 slow queries reported by mkqd appeared in the actual slow log…
Post: Slow Query Log analyzes tools
September 6, 2006 By 83 Comments
…Slow Query Log – Especially after the changes to log all queries slow query log may be growing too rapidly to follow, so we implemented slow query log filter (based on parse_mysql_slow_log…
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
…to get amount of IO per query or per Select. It is good to check…How to get CPU consumption per query ? You can take a look at procfs for MySQL process: root@ubuntu:/var/log/mysql…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…to an hour long, if we’re discussing a lot of things like how to build for massive scalability, how to…slow query logs in the stock MySQL server are extremely limited, and for serious analysis it’s basically mandatory to…
Post: Profiling MySQL stored routines
January 19, 2009 By 3 Comments
…queries are being executed. This is where Jeremy’s SHOW PROFILE patch – which is included in all Community tree based Percona MySQL…to check if it would be hard to implement configurable variable for switching between routine and query logging, so maybe one day we’ll be able to…
Post: How to load large files safely into InnoDB with LOAD DATA INFILE
July 3, 2008 By 28 Comments
…slow. Even simple SELECT queries might have to…mysql -e “set foreign_key_checks=0; set sql_log_bin=0; set unique_checks…to be capturing the bytes in per second. You can see how the curves are…
Post: Troubleshooting MySQL Upgrade Performance Regressions
February 15, 2012 By Leave a Comment
…query which performs differently between MySQL Server versions you should: Check Query Plan Run EXPLAIN to see if plans for the query are the same. Changing Query…
Post: Reasons for MySQL Replication Lag
July 29, 2011 By 6 Comments
…to analyze your replication traffic regularly with mk-query-digest (Percona Server marks Slave Thread in slow query log so it is easy to…to check the types and frequencies of queries but also how much IO they are causing and how many rows they analyzes. Changes could be…
