…how to read these, there’s a full explanation in our book, High Performance MySQL…to/slow.log By default, this outputs the top 10…to the query or the table. We explain how to…
Post: How fast can you sort data with MySQL ?
August 18, 2007 By 26 Comments
… table as I used for MySQL Group by Performance Tests to see how much MySQL can sort 1.000.000 rows, or rather return top 10 rows from sorted result set which is the most typical way sorting is used in practice. I tested full table scan….000.000 of rows were partially sorted but only 10 rows fetched from the data file and sent and only they are counted…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 12 Comments
…tables used by the above view, as stored in the data dictionary: mysql> select * from flexviews.mview_table…(dashboard_top_customers) to list the top 10 customers …how you can combine both types of views together. The complete method examples show how to create a complete refresh view which reads from…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
…how much of “load” is not covered by top queries, we have 10% in MISC which means that by reviewing these top…to gather more data about the underlying tables involved and the query execution plan used by MySQL…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 11 Comments
…data/mysql socket=/var/run/mysqld/mysqld.sock innodb_file_per_table = true innodb_data…to IO alignment yourself. In this case offset is correct, but file system is unaware how to align files properly. 4. Partition table…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…to provide reports to their clients. Clicks by day, by customer, top ads by clicks, top…data processing in MySQL, you’re going to end up heavily I/O bound. Listen to any of the talks at past MySQL conferences from…to think about how to avoid enormous tables that are hard to…
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
…table and so how much rows will be stored to temporary table. Sometimes it is enough to perform sorting or use temporary table…data from other tables. No information about using disk for sort or temporary tables MySQL…
Post: 3 ways MySQL uses indexes
September 12, 2009 By 27 Comments
…MySQL decides to pass it on. There are some workarounds you can use though. Using index to read data…from the same page but the rows itself can be scattered across many pages requiring potentially a lot of IOs. On top…
Post: Is it query which needs to be optimized ?
March 6, 2007 By 9 Comments
…then think how the queries they are looking to …FROM log GROUP BY page ORDER BY cnt DESC limit 10, the query to display top…to use different solutions, such as summary table. With MySQL 5.0 it is also easy to implement one by use of triggers. From…data sets if external filesort is used so make sure to…
Post: MySQL Slow query log in the table
May 31, 2007 By Leave a Comment
…how many queries were accumulated in the logs or finding 10…to SELECT * FROM slow_log ORDER BY start_time DESC LIMIT 100 you would find new queries coming to the top…table implementation in MySQL is well though of in regards to avoiding trouble. For example you can’t ALTER log table…
