June 19, 2013

Post: Is VoltDB really as scalable as they claim?

February 28, 2011 By 3 Comments

…In other words, the “unit of scaling” that is on the x-axis really shouldn’t be the server count, but rather the number of partitions in…of that, I’ll tell you: scaling a synchronously replicated, active-active master, fully ACID, always-consistent database to a 40-server…

Filed Under: Benchmarks, MySQL

Post: Advanced index analysis with mk-index-usage

November 11, 2010 By 2 Comments

…usage into tables in a database, so you can query them with SQL. …server, and store the results in my MySQL sandbox instance. The new option is –save-results-database…_id, db, tbl HAVING COUNT(*) > 1 ) AS qv USING(query_id, db,… these tables any way you want. The documentation includes a number of …

Filed Under: Insight for DBAs, MySQL

Post: Shard-Query EC2 images available

May 11, 2011 By 2 Comments

…in it’s configuration, so you can use this sample database…number of the flight. Some data hand updated.’; — – Table structure for table `ontime_fact` — CREATE TABLE…servers.txt” and run the following commands: $ cat servers…

Filed Under: MySQL

Post: Shard-Query adds parallelism to queries

November 15, 2010 By 18 Comments

…number of concurrent queries which each examine large amounts of data. Since a single query is single threaded in…in this blog post. Many database servers can add this parallelism natively, but most of those are not open source. In…

Filed Under: Insight for Developers, MySQL Tagged With: , , , ,

Post: Sphinx search performance optimization: multi-threaded search

January 16, 2013 By 10 Comments

…database whatsoever, it is only a matter of small changes to the sphinx configuration. The Plan First of…number of…table in MySQL to define those ranges, mixing it with sql…

Filed Under: MySQL Tagged With: , , ,

Post: Be productive with the MySQL command line

December 21, 2012 By 14 Comments

… MySQL servers, one day…of the Log Sequence Number during a given period of time. Instead of manually looking for the right line in the output of… SQL words. Instead of manually…of table and column names You can turn off this feature to get a quicker startup with -A Database changed mysql> select count…

Filed Under: Insight for DBAs, MySQL

Post: Handling big result sets

June 26, 2006 By 13 Comments

…count(*) from longf; +———-+ | count(*) | +———-+ | 5242880 | +———-+ And simple PHP script which retrieves all rows from the table…database‘); $time_start = microtime(true); // Performing SQL…server needs to convert millions of…while ($stmt->fetch()) { } printf(“Number of rows: %d.\n…in…

Filed Under: Insight for Developers Tagged With: ,

Post: Speeding up GROUP BY if you want aproximate results

March 7, 2008 By 24 Comments

…of visits per day. We had SQL logs in the database so It was pretty simple query: select sum(cnt) from (select count…server and I had to kill it in the end. The reason for slowness was of course huge temporary table…distribution but table is to large is to just limit it to first number of rows: mysql>…

Filed Under: Insight for Developers Tagged With:
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