… as many as …a SQL query optimizer and see how easy it is? ;-) Generative grammars like SQL can produce an infinite variety of queries. The query optimizer analyzes queries for common patterns the MySQL…rows in the `kind_type` table to be first, then look up matching rows in `title` by a…
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
…how many physical cores are connected to my bus, and because I chose to create six hash “buckets” in the table. This allows MySQL…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
…rows in the table orders (left operand), and so MySQL 5.5 prefers to do a PRIMARY index scan of the table orders resulting in…rows from orders table many times, and hash join is not that good if you need many scans of the right operand (in…
Post: To SQL_CALC_FOUND_ROWS or not to SQL_CALC_FOUND_ROWS?
August 28, 2007 By 57 Comments
…row in set (0.00 sec) mysql> explain SELECT SQL_NO_CACHE count(*) FROM count_test WHERE b = 666; +—-+————-+————+——+—————+——+———+——-+——+————-+ | id | select_type | table…
Post: Percona Server on the Raspberry Pi: Your own MySQL Database Server for Under $80
February 25, 2013 By 10 Comments
…many reasons for wanting a small MySQL database server: You’re a uni student who wants to learn the SQL language better and needs a…how about if you could setup a small Arch Linux ARMv6-based hardware device which runs Percona Server for MySQL, in a…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 23 Comments
…in the table: mysql> select count(*), count(distinct UniqueCarrier) from dim_flightG *************************** 1. row *************************** count(*): 58625 count(distinct UniqueCarrier): 29 1 row in…A SQL…many of the filter conditions are placed on attributes in the dimension tables…
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 64 Comments
…rows used from query syntax may be hard. Query Cache Storage Engines MySQL Query Cache now stores queries in…. Improve Manageability What is in the MySQL Query Cache ? How many hits did we get for this …SQL_CACHE_TTL from expiring as well as re-populating the cache after table update invalidated a…
Post: Tools and Techniques for Index Design Webinar Questions Followup
October 4, 2012 By 5 Comments
… in tools for query optimization to attend the new Percona online virtual training Analyzing SQL…relevant to current versions of MySQL. Q: How do the upcoming changes in MySQL 5.6 change the…a query, by counting how many lookups to index entries or table rows will be necessary for a given query in…
Post: Full Text Search Webinar Questions Followup
August 24, 2012 By 5 Comments
…rows on SQL and 20 on Sphinx). Also Sphinx does the relevance sorting by default, adding relevance sorting to the MySQL…in Sphinx shows how many rows each keyword matched, and then a total for the search expression. But I don’t know a…
Post: How is join_buffer_size allocated?
July 5, 2010 By 9 Comments
…MySQL configuration, we quite often want to know how…a special case. Unlike many…in special cases. A join buffer is allocated to cache rows from each table in a…
