… master. This can be useful if you’re trying to limit the amount of data sent over the wire, but it… that trouble is brewing. Or if you watch your MySQL server’s memory usage and you see that it’s starting to swap…: Incorrect information in file: ‘./mysql/servers.frm’ ERROR: 1033 Incorrect information in file: ‘./mysql/servers.frm’ Running mysql_install_db under strace, I…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 5 Comments
… most painful troubleshooting tasks with MySQL is troubleshooting memory usage. The problem usually starts like this – you have configured MySQL to use reasonable global… running MySQL in wild. I also wanted to share some troubleshooting techniques I use. Plot Memory Usage First I would like to see MySQL memory…_heap_table_size variable which allows you to limit size of MEMORY tables (the limit applies both to implicit and explicit ones) but…
Post: MySQL Server Memory Usage
May 17, 2006 By 21 Comments
… to worry about memory usage are quite understandable. If you configure MySQL Server so it uses too small amount of memory it will likey… memory needed for OS, File Cache and other applications. For 32bit envinronment you also should keep 32bit limits into account and probably limit…
Post: Profiling MySQL Memory Usage With Valgrind Massif
January 9, 2013 By 3 Comments
… memory profile slowly growing overtime, indicating a possible memory bug. Whatever the reason, there is a simple but powerful way to profile MySQL memory usage… complaining quickly. If you self compile, and those Valgrind-internal limits are still too small, you can easily change them before…
Post: MySQL Wish for 2013 - Better Memory Accounting
December 31, 2012 By 6 Comments
… stage information). Where we’re still walking blind with MySQL is resource usage – specifically Memory Usage. I can’t count how many time I… memory allocation and help to get MySQL on the memory diet. It would be easy to extend QA suite to check for peak memory usage… being able to limit memory usage by individual MySQL users or even track how much these users are using. Now as MySQL 5.6 is…
Post: MySQL Limitations Part 4: One thread per connection
October 27, 2010 By 14 Comments
… processes that communicate through shared memory or other means. It’s cheap to create a connection to MySQL, because it just requires… server. That increases the overhead from thread scheduling, and potentially memory usage as well. I feel like I’m forgetting some reasons… why I listed those as major limitations. And because MySQL is a multi-threaded database for Web usage that tends to be used…
Post: Dynamic row format for MEMORY tables
September 6, 2011 By 5 Comments
… features in the MEMORY storage engine (also known as HEAP) in MySQL has been one of the long-standing limitations caused by the… community to remove this limitation. In 2008 Igor Chernyshev of eBay implemented true-VARCHAR support for MEMORY tables for MySQL 5.0. Although…: 10069048 kB Here we can see that the performance and memory usage is about the same for both row formats. (Speaking very…
Post: Review of MySQL 5.6 Defaults Changes
October 8, 2012 By 10 Comments
… server ? We also speak about just pennies in terms of memory usage so why do not just default at 2000 ? innodb_file… variable strives to provide as MySQL is typically protected by Firewall to begin with. open_files_limit = 5000 strangely enough this is… referring to amounts of memory we have in the phones these days, I made in my Optimizing MySQL Configuration Webinar were heard…
Post: How much memory can MySQL use in the worst case?
February 12, 2009 By 17 Comments
…’s the formula to compute mysqld’s worst-case maximum memory usage?” Various formulas are in wide use, but none of them… * 1024 * 100); Query OK, 0 rows affected (2.34 sec) mysql> select get_lock(@a, 1); +—————–+ | get_lock(@a, 1) | +—————–+ | 1… compute the maximum possible memory usage, and there cannot be because there are some things that have no defined limits. It’s not…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
… in such a scenario, since inequality ends index usage. Actually in this case index on (A,B) … of indexes. The indexes can’t fit in memory anymore. How does this affect performance? A: Typically … in recent MySQL versions. However it is often too many. Instead of thinking about hard limit of indexes …
