In query examinations it is often interesting which columns query needs to access to…to the columns with table prefix it may take a while to figure our where these columns come from and so how…
Post: A quest for the full InnoDB status
October 31, 2008 By 4 Comments
…in very long execution times for even simplest queries, or a huge deadlock. In such rare cases SHOW ENGINE InnoDB STATUS often fails to…a relatively simple way to access…
Post: Visualization tools for pt-query-digest tables
August 31, 2012 By 6 Comments
…columns to show; * filtering queries by hosts; * filtering reports by different query conditions; * graphing reports; * explaining queries…queries. Despite its lack of ability to save predefined reports in the web interface for easy access, it does have a…
Post: InnoDB vs MyISAM vs Falcon benchmarks - part 1
January 8, 2007 By 117 Comments
…to show graphics with comments READ_PK_POINT Query: SELECT name FROM $tableName WHERE id = %d The very common query with access…query is similar to previous READ_KEY_POINT with only different the values of accessed column is stored in…
Post: The MySQL optimizer, the OS cache, and sequential versus random I/O
April 28, 2008 By 17 Comments
…how I measured the performance on a join between a few tables in a typical star schema data warehousing scenario. In short, a query…columns are indexed on every table, and there’s a separate index on every column in the WHERE clause. Here’s the query…
Post: Falcon Storage Engine Design Review
January 12, 2007 By 19 Comments
…how much performance it will give. As “SHOW TABLE STATUS” is not showing index sized in the release we tested it is hard to see how…columns which are in the index. I think this is big gotcha as having index covered queries…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
…to schedule sequential read-ahead, random read ahead ? HT: InnoDB schedules a sequential read-ahead when it notices an ascending access…columns are the first columns in an index. I think it is sound design practice to make the foreign key to…
Post: Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
… a…COLUMN v VARCHAR(1); Query OK, 4194304 rows affected (1 min 1.97 sec) Records: 4194304 Duplicates: 0 Warnings: 0 mysql> SHOW…how performance is affected when turning expand_fast_index_creation on. Here and in later examples I’m extending the VARCHAR column to…access for subsequent DML statements. In…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
…column. In such cases it indeed might be better to add another index. Q: We have a…A: Typically you do not need all your indexes to be in memory only those portions of them which are accessed…to redesign schema and queries to make it work well. Q: how does a index be used having an index on one column…
Post: PBXT benchmarks
April 8, 2007 By 14 Comments
…access patterns. Results for your workload are likely to be different.) There are interesting results I want to show…query is similar to previous READ_KEY_POINT with only different the values of accessed column is stored in…
