June 20, 2013

Comment: Converting Character Sets

June 12, 2013 By 22 Comments

… explained in the manual – http://dev.mysql.com/doc/refman/5.1/en/alter-table.html “For a column that has a data type of VARCHAR or one of the TEXT types, CONVERT TO CHARACTER SET will change the data type as…

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Post: Virident vCache vs. FlashCache: Part 2

May 17, 2013 By 3 Comments

…in use for all of the benchmarks on both systems. The benchmark tool used was sysbench 0.5 and the version of MySQL…of data (32 tables…changes…

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Post: Implications of Metadata Locking Changes in MySQL 5.5

February 1, 2013 By 9 Comments

…of MySQL 5.0 and 5.1 installations that would upgrade or are in the process of upgrading to MySQL…type of queries to the table, we know that writes would be blocked anyhow for the entire duration of…

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Post: InnoDB Full-text Search in MySQL 5.6 (part 1)

February 26, 2013 By 1 Comment

…of actual data. NOTE 3: Also, keep in mind that I used the community editions of MySQL 5.5.30 and MySQL…of the other I_S tables, I do find that the number of rows in I_S.innodb_ft_index_table is changing…

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Post: InnoDB Full-text Search in MySQL 5.6: Part 2, The Queries!

March 4, 2013 By 7 Comments

…of data, one which is the text of…of that sort, and we were looking for queries containing the word “MySQL” – odds are that an article which has 10 instances of “MySQL…of the types of queries that you’re expecting your users to run. In…

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Post: Data mart or data warehouse?

July 15, 2010 By 14 Comments

…of data to the source tables. The goal of this methodology is the 100% accurate description of historical data from the operational system in…in which the dimensions are normalized. This type of schema is usually called a snowflake schema. The three table item/category/item_category tables in…

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Post: Using Flexviews - part two, change data capture

March 25, 2011 By 26 Comments

… this type of software was not available for MySQL. Change Data Capture can be used to: Monitor a database table, or tables for changes. …changes Now that the changelog has been added, any changes to `test`.`demo` will automatically be captured. Insert data in one transaction (two rows): mysql…

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Post: MySQL 5.5 and MySQL 5.6 default variable values differences

February 21, 2013 By 8 Comments

…_5_30/data/dpe0 | /mnt/data/sandboxes/msb_5_6_10/data/dpe0 | | TABLE_DEFINITION_CACHE | 400 | 1400 | | PORT | 5530 | 5610 | | QUERY_CACHE_TYPE | ON… differently now. The query_cache_type is now off by default with default size of 1MB while in MySQL 5.5 and before it… one of the component of purging fine tuning in MySQL 5.6 innodb_file_per_table is now ON by default. This is very big change…

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Post: How Percona does a MySQL Performance Audit

November 24, 2008 By 17 Comments

…tables and so forth. If the server is heavily loaded or has a lot of data…table. Queries can be rewritten. Indexes and data types and table structures can be changed…

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Post: On Character Sets and Disappearing Tables

June 21, 2012 By 1 Comment

… with a mismatched data type. For instance, if we have these two tables: CREATE TABLE foo ( i INT… exists in the temporary tables that were created as part of the ALTER operation and can be found in the data…’s something of an inconsistency present when MySQL won’t allow us to change an FK-referenced …

Filed Under: Insight for DBAs, MySQL
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