…, implicit relationship to parent”> <column name=”id” primaryKey=”true”> column> <column name=”parent_id”>
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
…=latin1 1 row in set (0.00 sec) In previous versions of MySQL, you can create two indexes with the same columns (in… closing of this bug (although this was initially accepted as a bug as early as 2005!). The report explains more in detail what… for filtering on both columns, but also for filtering by just the first one. Why can’t MySQL enforce this kind of…
Post: MySQL Query Patterns, Optimized - Webinar questions followup
June 3, 2013 By 2 Comments
… gave a presentation on “MySQL Query Patterns, Optimized” for Percona MySQL Webinars. If you missed it, you…folks who asked the great questions. I answered as many as we had time for during the session,… may be to add a column to the table, and populate the rows you want to choose (movies,…
Post: Follow these basics when migrating to Percona XtraDB Cluster for MySQL
May 1, 2013 By 10 Comments
…XtraDB Cluster (PXC) for MySQL is a hot thing right now and some users… replace in short term. Control Your Auto-Incrementing Columns PXC/Galera controls auto-incrementing values internally within … good if your async master can use ROW based binlog format as well to achieve better consistency, if …
Post: Understanding the maximum number of columns in a MySQL table
April 8, 2013 By 5 Comments
… specified what fields where on what screen for entering, as well as any constraints as to what could be entered. For example, if… around the maximum number of columns is this: /* Hack to avoid bugs with small static rows in MySQL */ reclength=max(file->min_record… as what I can create. That’s right folks, in MySQL 5.6 you can create a table with a few more columns…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
… can have all sorts modifications floating around as long as they don’t touch the same row. Row locks are held for modifications until… MySQL replication from this instance, since MySQL replication is asynchronous. What about semi-sync MySQL replication? It’s actually much worse than Galera. As… the ‘joined’ column to the users_groups table so we don’t need to update the parent group row so often? INSERT…
Comment: MySQL Partitioning - can save you or kill you
April 30, 2013 By 45 Comments
… size of the partitions, the whole partition can be cached, as opposed to a single table, where probably only recently read… you do queries on any other column, these could easily be quicker on a partitioned table, as Mysql can fire off one thread… is easier and quicker than deleting a few hundred thousand rows… for example, if you need to delete. However, thank you…
Post: Eventual Consistency in MySQL
November 18, 2011 By 8 Comments
…mysql> SELECT * FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE REFERENCED_TABLE_NAME IS NOT NULL\G *************************** 1. row … | SELECT Bar_ibfk_1.ID AS `test.Bar.ID` FROM test.Bar AS Bar_ibfk_1 LEFT…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
… row in set (0.00 sec) session2 > ALTER TABLE test add column c char(32) default ‘dummy_text’; Query OK, 2 rows affected…, 0 rows affected (0.00 sec) session2 > ALTER TABLE test add column c char(32) default ‘dummy_text’; Query OK, 2 rows affected… was never an issue when the application was using MySQL version < 5.5 as the datastore. There was another interesting case this…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…: one row. An impression per day becomes a fixed overhead of storage size. So, you actually have as many rows as you… key columns. And not only will every index be a little narrower, the table will now contain only half as many rows. That… can save that work by either using MySQL 5.1′s row-based replication, or in MySQL 5.0 and earlier, doing the…
