… InnoDB table: SELECT non_key_column FROM tbl WHERE key_column=x This query will roughly be evaluated in ….89G 1.53G 1.89G 1.53G Innodb_data_reads 120552 123872 100551 103011 77213 Innodb_pages…, while in MySQL 5.5 no read_ahead was done because the access pattern was not sequential. Another thing to …
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
…Access Traditionally, MySQL always uses Nested Loop Join to join two or more tables. What this means is that, select rows from first table participating in…access pattern. BKA is available in both MySQL 5.6 and MariaDB 5.5. You can read more about BKA in MySQL…Another…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
…MySQL. The moment you give someone access to MySQL Server, all MySQL Security guarantees is you can stop one from seeing data…tables in MySQL 5.1 Disk Space For MyISAM tables hosting providers used to use disk quotas for MyISAM tables…
Post: A recovery trivia or how to recover from a lost ibdata1 file
June 3, 2011 By 7 Comments
…access to the table but, although MySQL was not complaining, the data was not available. An “alter table…tables With all this in place, recovery the data was just another Bash script: #!/bin/bash CURRENT_ID=1 mysql…
Post: Data mart or data warehouse?
July 15, 2010 By 13 Comments
…from another system. This might be an ERP application, the logs from a web application, data from manufacturing systems or even data from radio telescopes. This data…Data is often aggregated in many different ways. Aggregated data may be stored in aggregated tables so that it can be accessed…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…data was hashed over the values in the date_id column. There will be another…accessed data for all configurations of more than one node. This would not be the case in normal circumstances. The extra data… data from 1988 to 2010′; mysql> use ontime1; Database changed mysql> show table status like…
Post: Using Flexviews - part two, change data capture
March 25, 2011 By 11 Comments
…data. Using the aggregated data can significantly improve query response times compared to accessing the non-aggregated data… The Binary Log is the MySQL log which records changes to tables in the database. FlexCDC … SBR changes from a MySQL master. I’ll talk more about that in another blog post. …
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
… with MySQL we can use Innodb_data_reads , Innodb_data_writes,…CONNECTIONS: 0 ACCESS_DENIED: 0 EMPTY_QUERIES: 13099 In this case…great amount of related data from mk-query-digest report: # Overall…table 1% yes, 98% no # Tmp table on 1% yes, 98% no In…to have system handle another 1000 of such queries …
Post: Innodb vs MySQL index counts
November 29, 2011 By 6 Comments
…From my testing, I saw that the error only happened when the table was opened and not on every table access… table, which exists in Percona Server 5.1, but doesn’t appear in MySQL until…Another solution might be to figure out what index was missing via the Innodb data dictionary (more on that in…
Post: Troubleshooting Relay Log Corruption in MySQL
August 2, 2008 By 5 Comments
…in this case you can’t clone another slave. You also can’t use classical method of recovery from backup – because you would need relay logs to roll forward, and they are corrupted. You can either re-clone the data from…
