… 1GB. And a single query may cause multiple sort buffers to be allocated. You can’…DISTINCT and UNION may/will also create temp tables; the same applies to views and probably some other … 100); Query OK, 0 rows affected (2.34 sec) mysql> select get_lock(@a, 1); +—————–+ | get_lock(@a, 1) | …
Post: Investigating MySQL Replication Latency in Percona XtraDB Cluster
March 3, 2013 By 13 Comments
…setup from typical data center latency point of view though the server hardware is not the most …on multiple nodes. There is an option you can enable to get fully synchronous replication behavior: mysql> set…transactions ? To test this I have created the copy of sbtest table and will run a long update…
Post: Full Text Search Webinar Questions Followup
August 24, 2012 By 5 Comments
…create an InnoDB FT index before declaring the `FTS_DOC_ID` primary key column properly, MySQL… S. asked: Q: If searching on multiple terms, can you get Sphinx to… assume the search would necessarily do table-scans. Jessy B. also asked: Q… see some of the folks who viewed my Full-Text Search Throwdown …
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
…” stage – if it is multiple statement transaction. Innodb …mysql tables in use 1, locked 0 is number of tables used by transaction in question (meaning it was accessed) and number of tables… written. Created pages is empty pages created in buffer …queries in queue 1 read views open inside InnoDB Main …
Post: Differences between READ-COMMITTED and REPEATABLE-READ transaction isolation levels
August 28, 2012 By 3 Comments
…MySQL thread id 4, OS thread handle 0x7f8dfc35d700, query id 47 localhost root show engine innodb status In the employees table…multiple version concurrency control) and it is accomplished using row versioning and UNDO information. In REPEATABLE READ InnoDB also creates… a read view is created at the …
Post: Intro to OLAP
July 12, 2010 By 10 Comments
…. Using materialized views to automate that aggregation process. Comparing the performance of OLAP with and without aggregation over multiple MySQL storage engines at… information to the user as a ‘pivot table‘ or ‘pivot report’. While you could create such a report in a spreadsheet, the…
Post: Fishing with dynamite, brought to you by the randgen and dbqp
November 16, 2011 By Leave a Comment
…the test: ./dbqp.py –default-server-type=mysql –basedir=/path/to/Percona-Server –suite=randgen… Internationalization package\’s Views translation module.’ The test value was …_per_table and that we used Xtrabackup’s –parallel option. I also wanted to create multiple schemas…
Post: Benchmarking single-row insert performance on Amazon EC2
May 16, 2012 By 17 Comments
…’s come to the MySQL configuration. MySQL Configuration I used Percona …Table Structure The table structure of the table with no secondary indexes is as follows: CREATE TABLE `purchases…the graphs have a better view of the whole picture. Note,…of the B+tree, having multiple buffer pool instances to …
Post: Can Innodb Read-Ahead reduce read performance ?
June 26, 2007 By 2 Comments
…merged recs, 3876269 merges Hash table size 25499819, used cells …created 2867101, written 37374308 1445.95 reads/s, 0.00 creates… queries in queue 12 read views open inside InnoDB Main … read-ahead performance plus multiple threads doing scattered O_… in this project from MySQL AB side) – to improve…
Post: Why Index could refuse to work ?
September 8, 2006 By 15 Comments
…view): mysql> explain select * from article where article_id=10; +—-+————-+———+——+—————+——+———+——+——-+————-+ | id | select_type | table…look at article table: CREATE TABLE `article` ( `article_id` varchar… there are multiple strings possible for…
