$wgDBtransactions gets set to true if using InnoDB tables.  Is there  an advantage to using InnoDB tables? The disadvantage is that with MySQL there is a file, ibdata1, that  seems to grow endlessly if InnoDB tables are used.  See http://bugs.mysql.com/bug.php?id=1341 We're wondering if we should just convert everything to MyISAM.  Any  thoughts?

Ok I got this resolved. I found out I can change the database type in myPHPadmin and it was executing the same shell command (ALTER table). If the leaders of Mediawiki are recommending InnoDB and thats the type of DB that it now defaults to for a new installation, I should convert it to InnoDB and trust that its a good decision and wont cause any problems later. So I was able to change the database type in MyPHPAdmin. I did it for each table. The options are available in MyPHPadmin: Select the table you want to change -> "Operations" -> Change type to InnoDB I'm also changing the "collation" from "utf8_unicode_ci" to "binary", for a few tables. What I did was install the latest MW in a test database and see what options it was using for all the tables and then change the old tables to match the options in the test database. I saw there are two tables that have their own set up in the new version too (hit counter, and search index) so I left them alone. ________________________________ From: Eric K &lt;ek79501(a)yahoo.com&gt; To: MediaWiki announcements and site admin list < mediawiki-l(a)lists.wikimedia.org&gt; Sent: Saturday, December 3, 2011 11:18 PM Subject: Re: [Mediawiki-l] Mysql ISAM vs InnoDB When I installed my wiki for the first time a couple of years ago, MyISAM was chosen as the default option so I went with that. I was looking up the history of this list for comments on InnoDB vs MyISAM. I've seen people, including Brion (below), recommending InnoDB. Rob Church also had the same opinion: http://wikimedia.7.n6.nabble.com/MYISAM-or-InnoDB-best-for-Mediawiki-td6917… However for example on the following article, some disadvantages of InnoDB are talked about: http://www.mysqlperformanceblog.com/2009/01/12/should-you-move-from-myisam-… So it seems like both of them have advantages and disadvantages and so I'm really confused about what to do - whether to stay where I am, or convert to InnoDB. So my first questions are: - I keep regular backups and haven't had DB problems in the past. Should I really move to InnoDB? If I had to convert the DB, I can always do it in the future without any problems, correct? - Will I have any problems later if I stay on MyISAM? I have MW 1.16.15 and am going to upgrade to 1.18.0. I have Shell access. Now the DB has mixed tables (Semantic MW did its setup using InnoDB). Its about 1GB in size. The wiki isnt too big, but say the DB size could go to a few GBs in a few years. Suppose I decided to move to InnoDB. My next questions were: - Whats the procedure for this conversion? I will be working on a copy of the database. - I'm assuming there will be no long term issues about website speed and reliability or anything else. thanks Eric ________________________________ From: Brion Vibber &lt;brion(a)pobox.com&gt; To: MediaWiki announcements and site admin list &lt;mediawiki-l(a)Wikimedia.org Sent: Tuesday, December 5, 2006 8:48 PM Subject: Re: [Mediawiki-l] Mysql ISAM vs InnoDB -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Jim Hu wrote: > $wgDBtransactions gets set to true if using InnoDB tables. Is there > an advantage to using InnoDB tables? > The disadvantage is that with MySQL there is a file, ibdata1, that > seems to grow endlessly if InnoDB tables are used. See > http://bugs.mysql.com/bug.php?id=1341 > We're wondering if we should just convert everything to MyISAM. Any > thoughts? MyISAM tables are subject to a much higher likelihood of data corruption, and cannot be read consistently (eg for backups) without locking the database. You may notice that the majority of complaints about corrupt tables involving MediaWiki are about the 'searchindex' table, which is created as MyISAM due to the requirements of the fulltext index. In most wiki situations your database will indeed only grow, so the table space not reclaiming disk space on deletions is usually not a problem. In the wiki, all editing history is retained, and the space from the rare small records that are actually removed will simply be taken up by further edits. If you for some reason want to import a lot of data, then delete it all, then never work with any database data ever again, well... that's pretty weird. ;) But as suggested in your link you can use per-table InnoDB spaces in recent versions of MySQL, or you can use the more fragile MyISAM tables, or you can "defragment" the table space by dumping it out, deleting the space, and reimporting it. In some situations MyISAM tables may also be faster, which could be useful for certain kinds of statistical or other use. - -- brion vibber (brion @ pobox.com) _______________________________________________ MediaWiki-l mailing list MediaWiki-l(a)Wikimedia.org http://mail.wikipedia.org/mailman/listinfo/mediawiki-l _______________________________________________ MediaWiki-l mailing list MediaWiki-l(a)lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/mediawiki-l _______________________________________________ MediaWiki-l mailing list MediaWiki-l(a)lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/mediawiki-l