On Wed, 5 Sep 2012, Stewart Smith wrote: [Oracle and MySQL]
They've switched to an "open core" model. Some plugins are closed source. e.g. PAM authentication (both MariaDB and Percona Server have open source equivalents, even with more features than the closed one).
iX 8/2012, a German magazine, has a longer article about the "MySQL universe" describing forks and tools around it. It focuses on Percona in particular. If you don't mind I summarize some of it for hopefully interested people here. The benchmark team left MySQL AB in Aug 2006 founding Percona. They continued to work on the GPL code of the storage engine InnoDB. The result is XtraDB. They offer MySQL (5.1 and 5.5) compatible versionds, with some extentions related to performance, monitoring and diagnosis. XtraDB can change block size without compilation - good for SSDs. You can configure FlashCache, a SSD backed buffer to increase performance. Under Linux it is using a kernel module developed in 2010 by Mohan Srinivasan and Mark Callaghan for Facebook. Percona has a mechanism to boost the warm-up of RAM hungry instances. It uses a LRU (last recently used) list to restore the buffer. The list is written all five minutes when the DB is up. You can preconfigure some frequently used SQL queries to be executed at start-up (in --init-file) to prefill the cache. There is an additional metadata schema INFORMATION SCHEMA for statistics, e.g. to see pages cached, client statistics.. e.g. an easy way to find clients and particular queries. innodb_lazy_drop_table is used to remove the related cache pagies genyly in the background to avoid a complete cache lock for other queries. XtrBackup allows a table backup without table locks, as well as incremental backups, and a compressed send-off to a backup server. The Percona tools offering various helpers. e.g. pt-duplicate-key-checker, pt-online-schema-change for lock free schema changes, pt-query-advisor to analyse the slow log, pt-visual-explain to show explains as a tree, pt-config-diff compares servers etc. Recently Percona introduced a XtraDB cluster. I may look into it soon. I found it quite interesting:-) Regards Peter