…than InnoDB when the database is cold, but the opposite is true when the database is hot. SSB …were built using ALTER TABLE fast index creation (merge sort). For the MyISAM tests I used …datadir=/mnt/mysql56/data basedir=/usr/local/mysql socket=/var/lib/mysql/mysql.sock user=justin innodb_buffer_pool_…
Post: Open Source, the MySQL market (and TokuDB in particular)
May 10, 2013 By 13 Comments
… not because it is “free” as in “a free cloud database account,” rather it’s because it is “free” as in… business they failed to attract paying customers and had to merge with SkySQL. I name that a business failure (even though… find some grains of truth in the article “Dead database walking: MySQL‘s creator on why the future belongs to MariaDB.” To…
Post: High-load problems? Investigate them with 'pt-query-digest'
April 23, 2013 By 2 Comments
… Percona Toolkit for MySQL called pt-query-digest. One customer was suffering from periods of high load on their database server, leading…. Rewriting that query (actually the customer removed it altogether, by merging it with another query that ended up having a much… without issues. If you regularly work with MySQL databases, getting familiar with Percona Toolkit for MySQL will let you do more work, in…
Post: Percona XtraBackup 2.0.7 for MySQL available for download
May 6, 2013 By 1 Comment
… only open-source, free MySQL hot backup software that performs non-blocking backups for InnoDB and XtraDB databases. This release is the… directory, and were not removed when incremental backups has been merged. Fixed by removing files corresponding to tables that are missing… #1166888. Package dependency has been changed from abstract mysql to real /usr/bin/mysql file, because rpm packages from Oracle no longer…
Post: More on MySQL Error Messages
April 6, 2011 By 9 Comments
… ran into during last couple of days. mysql> drop database test; ERROR 1010 (HY000): Error dropping database (can’t rmdir ‘./test/’, errno: 17… to MySQL in database directory. MySQL will only remove files it knows about such as “.frm” or “.MYI” when it is dropping the database… description in addition to error code, this would make our merge process a lot more complicated, so it is a lot…
Post: The Optimization That (Often) Isn't: Index Merge Intersection
December 14, 2012 By 6 Comments
…, MySQL 5.0 and later changed this situation with the introduction of the “index merge” optimizer plan. The basic idea behind index merge… about what this means in the context of index merge, it means that MySQL is really looking at a search space closer…-session: SET [GLOBAL|SESSION] optimizer_switch=”index_merge_intersection=off”; This is the database equivalent of kicking the door in when you…
Post: MySQL Limitations Part 4: One thread per connection
October 27, 2010 By 14 Comments
… way MySQL handles connections, allocating one thread per connection to the server. MySQL is a single process with multiple threads. Not all databases… use, NotABug. I’m thinking of the lack of sort-merge joins or intra-query parallelism, for example. It would be… it were, it wouldn’t be a great OLTP web database too. MySQL replication is one of the core, fundamental features — and…
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
… ? You can take a look at procfs for MySQL process: root@ubuntu:/var/log/mysql# cat /proc/19018/stat 19018 (mysqld) S… 55.41M 5.15k 3.88k 258.55k 1.46k # Merge passes 0 0 0 0 0 0 0 # Tmp tables… wai 0 0 0 0 0 0 0 0 # String: # Databases # Hosts localhost # InnoDB trxID 3BBF3B55 (1/0%), 3BBF3B5A (1/0…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… constantly referring to the amazing MySQL manual, especially the option and variable reference table. But…fileblogpercona.commanual socketblogpercona.commanual sort_buffer_sizeblogpercona.commanual Sort_merge_passesblogpercona.commanual Sort_rangeblogpercona.commanual Sort_rowsblogpercona.commanual …
Post: Is there room for more MySQL IO Optimization?
January 3, 2013 By 11 Comments
… database server for those things which need to be cached — system files, binary log, FRM files, MySQL MyISAM system tables etc. Starting MySQL… able to issue many outstanding requests which when can be merged on OS level or RAID controller so we should expect… experiment with even in regards to such a minor item – Database Scientists will never have their job complete.
