… involving the McAfee MySQL Audit Plugin and would like to share my experience in this post. Auditing user activity in MySQL has traditionally been… understand why that is the case. Maybe someone more knowledgeable in MySQL internals can enlighten me here. – audit_record_objs : List of… the lines I had to add to my config file for the plugin to work (plus one commented line for switching between…
Post: The small improvements of MySQL 5.6: Duplicate Index Detection
May 31, 2013 By Leave a Comment
… Index Detection I commented about this on my last webinar, but did not have time to analyze it in-depth. If you… do something like this in MySQL 5.5, you will succeed without errors or warnings: mysql> ALTER TABLE test ADD INDEX (col2); Query OK… explains more in detail what the “will be disallowed in a future release” means. In MySQL 5.7 the checks will be stricter: in the…
Post: Understanding the maximum number of columns in a MySQL table
April 8, 2013 By 5 Comments
…_name)+2) (bytes) + length of all comments (in bytes) + length of all intervals (for ENUM, SET) in bytes. If you use that as… (REC_MAX_N_FIELDS – DATA_N_SYS_COLS * 2) Which adds up to (1024-1)-3*2=1017 which is exactly…).”‘) COMMENT ‘”.cname($_,254).”‘,\n”; } chop $sql; chop $sql; $sql.=”);”; print $sql; So the maximum number of columns for a table in MySQL is…
Post: How to Identify Bad Queries in MySQL
January 10, 2011 By 16 Comments
…in knowing whether I’m missing anything, but I believe the definition of badness in this article is fairly complete. (Post comments…finds queries or groups of queries that add too much load to the system… in MySQL for years. This is necessary for determining whether a group of queries completed in…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…o_orderdate >= ’1993-08-01′ and o_orderdate < date_add( ’1993-08-01′ ,interval ’3′ month) and l_returnflag =…_phone, n_name, c_address, c_comment order by revenue desc LIMIT 20; In-memory workload Now let’s …not in MySQL 5.6, is that because of a bug in MySQL 5.6 code? As MRR was used in both MySQL 5…
Post: Moving Subtrees in Closure Table Hierarchies
February 14, 2011 By 18 Comments
…comments, personnel org charts, or nested bill-of-materials. Sometimes it’s tricky to do this in SQL…new node, you just have one descendant to add, joined to all the paths of its ancestors….in FROM clause.” We can’t DELETE and SELECT from the same table in a single query in MySQL. But we can use MySQL…
Post: What Linux Distribution do you use to run MySQL ?
December 14, 2012 By 17 Comments
In the last poll we discovered some 90% of responders run MySQL on Linux which is not totally a surprise. Number of… pool to see what specific Linux distributions are most popular in MySQL space hence this is the poll for today. Please answer… is missing please ether select the closest in the list or add the comment so I can add it to the pool. [poll id…
Post: MySQL Configuration Wizard Updated
January 26, 2012 By 5 Comments
…to yourself. The new release also adds features like downloading the configuration files…MySQL behaviors. These are the kinds of things that Drizzle fixes — and should be fixed by default in MySQL…in the comments. We hope this suite of free browser-based tools helps you become a more productive MySQL…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… and Created_disk_tmp_tables, I’ll paste in mysql> show global variables like ‘%table_size%’; +———————+———–+ | Variable_name | Value | +———————+———–+ … my analysis for sending, add in things I may have noticed along the way (comments on backups, for example) …
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
… hit to happen. This means if you would place dynamic comments in the query, have extra space or use different case – these… simply preform select to retrieve data from table. Avoid comment (and space) in the start of the query – Query Cache does simple… application – You can’t change how it works with MySQL to add caching but you can enable query cache so it works…
