…get…tables> <table name=”parent” comments=”Parent table“>
Post: Implementing SchemaSpy in your MySQL environment
June 4, 2013 By 2 Comments
Post: The small improvements of MySQL 5.6: Duplicate Index Detection
May 31, 2013 By Leave a Comment
… we will get a warning (note severity, to be exact): mysql> ALTER TABLE test ADD … practice to avoid this is always naming your keys with a consistent pattern… not be necessary for MySQL 5.6? Let’s have a look … it does not detect all cases. For example: mysql> alter table test add index redundant (…
Post: Experiences with the McAfee MySQL Audit Plugin
May 23, 2013 By 4 Comments
…in and didn’t get significant differences between either… to the log (all the lists in these…MySQL internals can enlighten me here. – audit_record_objs : List of database objects (tables… possibilities of extending MySQL‘s behavior in a way … using MySQL in PCI or SOX compliant environments, to name …
Post: MySQL Query Patterns, Optimized - Webinar questions followup
June 3, 2013 By 2 Comments
…get skewed results. For instance, if there’s a gap of id’s…the index. Example: WHERE (last_name, first_name) = (‘Karwin’, ‘Bill’); Q: On …MySQL to scan the `title` table first, grouping by kind_id in index order. This made the first table…’t present the details of all the tables and columns. It …
Post: Understanding the maximum number of columns in a MySQL table
April 8, 2013 By 5 Comments
…those using MySQL, Percona Server, MariaDB or any other of the MySQL branches/forks, you get to have…17+2*(strlen(field_name)+2) (bytes) + length of all comments (in bytes) + length of all intervals (for ENUM… columns in a MySQL table. So what’s the maximum number of columns in a MySQL table? Well.. I…
Post: How to recover table structure from InnoDB dictionary
April 22, 2013 By 4 Comments
…gets created it will have minimal `ID` among the indexes of the table. mysql> select * from SYS_INDEXES WHERE TABLE_ID=741; +———-+——+———————+———-+——+——-+———+ | TABLE_ID | ID | NAME…
Post: Galera Flow Control in Percona XtraDB Cluster for MySQL
May 2, 2013 By 5 Comments
… find in standard async MySQL replication. It is …get behind? As I’ve mentioned before, Galera’s replication is synchronous to the point of ensuring transactions are copied to all…TABLES WITH READ LOCK on node3: [root@node3 ~]# myq_status wsrep Wsrep Cluster Node Queue Ops Bytes Flow Conflct time name…
Post: Eventual Consistency in MySQL
November 18, 2011 By 8 Comments
…mysql> SELECT CONCAT( ‘SELECT ‘, GROUP_CONCAT(DISTINCT CONCAT(K.CONSTRAINT_NAME, ‘.’, P.COLUMN_NAME, ‘ AS `’, P.TABLE_SCHEMA, ‘.’, P.TABLE_NAME, ‘.’, P.COLUMN_NAME…mysql -N | mysql -E *************************** 1. row *************************** test.Bar.ID: 42 DIY RI We can get… at all? There’s no…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
… locks. Let’s see the profiling information… like ‘Open%tables‘; +—————+——-+ | Variable_name | Value | +—————+——-+ | Open_tables | 30 | | Opened_tables | 0 |…get piled up waiting for table metadata lock bringing down the MySQL server or causing all the connections to get…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
…than adding a new one: Let’s say I have a table named PO that has a primary key…affect performance? A: Typically you do not need all your indexes to be in memory only …MySQL can avoid temporary table or filesort for group by by this column. This works because by scanning data in index order MySQL gets…
