… memory profile slowly growing overtime, indicating a possible memory bug. Whatever the reason, there is a simple but powerful way to profile MySQL memory… complaining quickly. If you self compile, and those Valgrind-internal limits are still too small, you can easily change them before…
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 fact that variable-length records were not supported by the engine. This is true for all MySQL… community to remove this limitation. In 2008 Igor Chernyshev of eBay implemented true-VARCHAR support for MEMORY tables for MySQL 5.0. Although…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just…_scanblogpercona.commanual server_idblogpercona.commanual shared_memoryblogpercona.commanual shared_memory_base_nameblogpercona.commanual show_slave_auth_infoblogpercona.commanual skip_…
Post: MySQL-Memcached or NOSQL Tokyo Tyrant - part 1
October 15, 2009 By 16 Comments
…, fast, and just works. When your dataset exceeds your memory limitations or the database can simply not keep up any more… do. Using this application I can then compare using MySQL to using MySQL + Memcached, and then to other solutions like Tokyo Tyrant… simple, fast, and just works. When your dataset exceeds your memory limitations or the database can simply not keep up any more…
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
… LIMIT which restricts how many rows will be examined MySQL will still print full number. Here is example: mysql> explain select * from lt limit… for sort or temporary tables MySQL always calls it “filesort” even if it is done in memory. Also it would not tell… BLOB fields can’t work with in memory temporary table. The other thing – since MySQL 4.1 sorting can be done with…
Post: MySQL Limitations Part 4: One thread per connection
October 27, 2010 By 14 Comments
… what’s seriously limiting MySQL in core use cases (links: part 1, 2, 3). This post is about the way MySQL handles connections… processes that communicate through shared memory or other means. It’s cheap to create a connection to MySQL, because it just requires… them. That’s why I listed those as major limitations. And because MySQL is a multi-threaded database for Web usage that…
Post: MySQL Wish for 2013 - Better Memory Accounting
December 31, 2012 By 6 Comments
… information). Where we’re still walking blind with MySQL is resource usage – specifically Memory Usage. I can’t count how many time… memory allocation and help to get MySQL on the memory diet. It would be easy to extend QA suite to check for peak memory… being able to limit memory usage by individual MySQL users or even track how much these users are using. Now as MySQL 5.6…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
… about 400GB of indexes. The indexes can’t fit in memory anymore. How does this affect performance? A: Typically you do… is a hard limit on amount of indexes you can have, which is 64 per table in recent MySQL versions. However it is often too many. Instead of thinking about hard limit of indexes I prefer…
Post: Review of MySQL 5.6 Defaults Changes
October 8, 2012 By 10 Comments
… which would mean limit disabled. Very few users actually need DOS prevention this 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: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 64 Comments
… Cache Storage Engines MySQL Query Cache now stores queries in local memory, which is great however memory amount might be limited especially in constrained environments as EC2. We could implement API which would allow one to use local memory…
