… those using MySQL, Percona Server, MariaDB or any other of the MySQL branches/forks, you get to have these odd limitations. Why do I… CASEDN fields which although not implemented in MySQL, the defines can still found in the source. Basically, it’s why we can’t…’s unique intervals, not actual intervals, so two ENUM columns both having the options ‘Y’ and ‘N’ will use less space in the…
Post: Enum Fields VS Varchar VS Int + Joined table: What is Faster?
January 24, 2008 By 30 Comments
…”, etc, etc. Frequently we suggest to change such fields to use ENUM column type, but is it really necessary (from performance standpoint… As you can see, ENUM and VARCHAR show close performance, while join performance degraded dramatically. Here is why: mysql> explain select SQL_NO…’d still suggest you to use ENUM, but now we can see that performance hit may not be as large as you expect…
Post: How (not) to find unused indexes
October 16, 2009 By 2 Comments
…why: CREATE TABLE `sales` ( `id` int(11) NOT NULL AUTO_INCREMENT, `customer_id` int(11) DEFAULT NULL, `status` enum…Â | NULL |Â 239 | Using where | +—-+————-+———+——+—————+——+———+——+——+————-+ 1 row in set (0.04 sec) mysql> EXPLAIN SELECT * FROM…
Comment: How to find wrong indexing with glance view
August 23, 2008 By 27 Comments
…, has_foto) 2) booleans – gender, has_foto; enums – available, looking_for, location; integer – age 3…Why? Because more than 70% percents of people will mark “show people with fotos only” and mysql can use index to filter records before fetching any rows. How much it will give? Not…
Comment: COUNT(*) vs COUNT(col)
April 25, 2007 By 45 Comments
…NOT NULL, `comment_karma` int(11) NOT NULL default ’0′, `comment_approved` enum(’0′,’1′,’spam’) NOT NULL default ’1′, `comment_agent` varchar(255) NOT…use that for a count, even if it is not a unique index. For instance: mysql…
Post: Lost innodb tables, xfs and binary grep
November 9, 2010 By 12 Comments
…verify your backup can be used to restore the database! If not automatically, do this …the system and how data was lost: MySQL had a dedicated partition on XFS…junk”, but I really needed it to. Why? Well, here’s few of the… this rather big table with integer and enum columns only, where we knew a …
