…MRR interface (which I explained in my previous post) to lookup the rows in table2. So this …set to 6M and read_rnd_buffer_size set to 6M, the query time for MySQL 5.6 becomes approximately equal to that of MySQL…query #3, in fact disabling both of these provided the best result for MariaDB 5.5 for in…
Post: Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
…Query scale to 20 nodes? Peter asked this question in comments to to my previous Shard-Query…query result set…MySQL storage nodes are supported. Amdahl’s law applies to the distributed processing. The results…
Post: MySQL Query Cache WhiteSpace and comments
March 20, 2008 By 9 Comments
…previous post on MySQL Query Cache Gerry pokes me as I’m all wrong and both comments and whitespace are fixed in MySQL…mysql> select /* inside comment4 */count(*) from fact where val like “%c%”; +———-+ | count(*) | +———-+ | 0 | +———-+ 1 row in set (8.82 sec) Looking at these results…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 22 Comments
…in the data set. mysql> select count(*) from dim_airport; +———-+ | count(*) | +———-+ | 396 | +———-+ 1 row in set…in another post. Complex queries Shard-Query was tested with the simple single table version of this data set in a previous blog post. Previous…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…Query. Each image comes pre-loaded with the data used in the previous Shard-Query blog post. The data in…row in set…query command, called pivot_results cd shard-query/ $ ./run_query < queries.sql | tee raw |./pivot_results…
Post: MySQL Query Cache
July 27, 2006 By 69 Comments
…Query Cache – meaning cache where execution plans are cached. MySQL Query Cache is not. It does not cache the plan but full result sets. This means it is much more efficient as query which required processing millions of rows now can be instantly summoned from query…previous item. Query…
Post: Air traffic queries in InfiniDB: early alpha
November 2, 2009 By 19 Comments
… time, datasize and query time to Google Spreadsheet so you can easy compare with previous results. There are different sheets for queries, datasize and… GROUP BY DayOfWeek ORDER BY c DESC; 7 rows in set (6.79 sec) Query Q2: mysql> SELECT DayOfWeek, count(*) AS c FROM ontime WHERE…
Post: Extending Index for Innodb tables can hurt performance in a surprising way
May 22, 2010 By 9 Comments
…query which previously ran so fast it hardly could be noticed. It however became a lot slower: # Old Schema mysql… 1 row in set (0.00 sec) MySQL Optimizer considers using both (a) and (a,b) indexes and in…rows in the selected plan, while using (a) index you can get result scanning only 1 row…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
…query into several, run in parallel and aggregate result sets. So if you’re dealing with large data sets and complex queries…
Post: MySQL net_write_timeout vs wait_timeout and protocol notes
July 8, 2007 By 1 Comment
In my previous post I mentioned you might need to increase … server with partial query received. Result set however comes back in multiple pieces and if you’re using mysql_use_result you can do… like mysql_ping because connection is in the stage of getting the data. You can’t even fetch couple of rows…
