… answers: Q: Can you compare the use of subqueries/multiple joins vs. multiple queries (e.g. temp tables)? For performance, it’s… were using the tuple syntax to look up values against multiple columns in a compound index, then the order would matter… more efficient in this case to force MySQL to scan the `title` table first, grouping by kind_id in index order. This made…
Post: Percona Live MySQL Conference 2013 wrap-up
April 29, 2013 By Leave a Comment
… the next few years despite the buzz created by NoSQL alternatives Despite the buzz, MySQL is still much more common than even… have succeeded without the support of our multiple service vendors including Ireland Presentations, Carleson Production Group, Tricord, the Hyatt Santa Clara, and…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…MySQL replication from this instance, since MySQL replication is asynchronous. What about semi-sync MySQL… really, really matters (really!). By enforcing replication to all …group_id) VALUES (100, 1); UPDATE groups SET last_joined=NOW(), last_user_id=100 WHERE id=1; COMMIT; How often might multiple…
Post: Wow. My 6 year old MySQL Bug is finally fixed in MySQL 5.6
August 30, 2012 By 2 Comments
…` (`i`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 mysql> select i,count(*) cnt from trunc group by i order by cnt desc limit 10; +————+——-+ | i | cnt… across the bug in the real application which would use multiple table and the column type was inconsistent between them… so…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 23 Comments
… the performance of queries against a MySQL database by distributing the work over multiple machines and/or multiple cores. This is similar to the… BETWEEN 1980 and 2011 GROUP BY dest.CityName ORDER BY 2 DESC; Finally, Shard-Query performance continues to improve when grouping and filtering is…
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
… run by the native database interface (MySQL): mysql> select word, md5(word), md5(reverse(word)), count(*) from words2 group by 1,2,3 order by 3…(*)` FROM words2 AS `words2` GROUP BY 1,2,3 ORDER BY NULL ) The other important optimization combines results from multiple queries together. This query…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
…are created by FlexCDC. The refresh algorithm computes changes in multiple transactions… as ol USING (order_id) -> GROUP BY (customer_id) -> ORDER BY total_price desc -> LIMIT 10; … <-- too high +------------------+ 1 row in set (0.68 sec) mysql> select sum(total_lines) from dashboard_customer_…
Post: Talking MySQL to Sphinx
April 19, 2009 By 4 Comments
… important. Sphinx mysql> select max(forum_id) as m,author_id as a from sptest group by author_id order by m desc limit….47 sec) MySQL mysql> select max(forum_id) as m,author_id as a from sptest group by author_id order by m desc limit… comes from its ability to scale almost linearly using multiple CPU cores and multiple nodes in the system. The raw scan speed…
Post: What would make MySQL Multiple Queries Usable ?
September 5, 2007 By 1 Comment
… and not significant gains in most cases. What would make MySQL Multiple Queries API more usable ? Allow to run queries in parallel…, as well as same set grouped by site (to show sites with most matches) as well to group by date to show history of matches per day. This could be very well optimized by performing search query…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…_time=1000 on MySQL 5.5.30 and testing multiple buffer pools on MySQL 5.5.30. Finally, MySQL 5.6.10…_page_lru where table_name like ‘%ssb%’ group by 1,2 ) sq order by pct_buffer_pool desc; +——————-+——————+——-+——+——+———+—————–+ | table_name | index_…
