Whats new in Flexviews 1.6.0RC1

• This is the first release candidate before the final release.  If no major bugs are uncovered, then the next release will be the first GA release. 
• Flexviews now has a test suite for all major features.  The creation of these tests uncovered a number of issues which have been resolved in this release. 
• All MySQL aggregate functions except GROUP_CONCAT are now supported. 
• A special aggregate function called PERCENTILE is now also supported.  The calculation uses a modified version of the GROUP_CONCAT based solution suggested by Roland Bouman for percentiles.  This function should be considered experimental.  Please report bugs if you find any.
• You can add indexes to enabled materialized views using SQL_API/add_expr
• Adding PRIMARY KEY indexes is no longer …

It may sound like a dramatic number, and that’s because it is. One thing that is enjoyable about working on beta applications is finding new solutions and better methods to improve the user experience. The original method for displaying the recent addition of overview analytics data in the beta version of Kontrollbase was to run [...]

Unlike COUNT(expression), COUNT(DISTINCT expression) is not a distributable function. That is, the expression can not be computed by looking at only the changed rows in the table change logs.



The following view can not be FAST refreshed with Flexviews today:

SELECT a a_alias, 
       b b_alias, 
       c c_alias, 
       COUNT(DISTINCT d) d_alias
  FROM T1
 GROUP BY a, b, c;

However, a dependent child materialization could be created to support the value for COUNT(DISTINCT d):

-- child materialization, dependent subview
--There will be one row for each DISTINCT value of d

SELECT a a_alias, 
       b b_alias, 
       c c_alias, 
       count(*) d_alias_cnt
  FROM T1
 GROUP BY a, b, c, d;

The original view could then be rewritten as:

SELECT a a_alias, 
       b b_alias, 
       c c_alias, …

I will be demonstrating the features of Flexviews as well as talking about how you can improve performance by:

• 
  
• pre-aggregating important tables for improved query performance
  
• pre-calculating joins on InnoDB using materialized views
  
• nesting incrementally refreshed materialized views to further improve performance
  

http://mysql.meetup.com/101/