… the Meta Data Locking behavior prior to MySQL 5.5.3 Metadata Locking behavior prior to MySQL 5.5.3 Prior to MySQL 5….000002 | | Sending data | 0.000040 | | end | 0.000003 | | query end | 0.000002 | | closing tables | 0.000003 | | freeing items | 0.000007 | | logging slow query….000004 | | Sending data | 0.000033 | | end | 0.000003 | | query end | 0.000002 | | closing tables | 0.000004 | | freeing items | 0.000009 | | logging slow query…
Post: How to convert MySQL's SHOW PROFILES into a real profile
February 20, 2012 By 12 Comments
… database to demonstrate: mysql> SET profiling=1; mysql> pager cat > /dev/null mysql> SELECT * FROM …| 0.046175 | 26.74 | 1 | 0.0461750000 | | Sending data | 0.018478 | 10.70 | 3 | 0.0061593333 | | … | 0.000002 | 0.00 | 1 | 0.0000020000 | | logging slow query | 0.000001 | 0.00 | 1 | 0.0000010000 …
Post: Write contentions on the query cache
September 5, 2012 By 5 Comments
…). Of course, I wanted to know more about how MySQL executes this query. So I used commands you’re … | | Sending data | 0.162272 | | end | 0.000008 | | query end | 0.000004 | | closing tables | 0.000032 | | freeing items | 0.000035 | | logging slow …
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
… they end up sending. In this case if I index the table I get the following record in the slow query log… which are found and returned up to the top level MySQL part for processing are counted the Rows_examined remains zero… is “const” MySQL does not count it as access to two tables. In case of “real” access to the data it will…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…MySQL…data_pending_readsblogpercona.commanual Innodb_data_pending_writesblogpercona.commanual Innodb_data_readblogpercona.commanual Innodb_data_readsblogpercona.commanual Innodb_data_writesblogpercona.commanual Innodb_data…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 5 Comments
… server and Com_stmt_send_long_data to see whenever sending long data feature is used …: mysql> select sum(data_length+index_length) from information_schema.tables where engine=’memory’; +——————————-+ | sum(data… memory leaks like valgrind are too slow to run in production. So the …
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…data and the IO is slow (when the FS cache is cold, IO to slow…MySQL 5.6.10 at the MySQL 5.5.30 data…pf | p2_pf | +—–+———————-+———–+———-+———–+———–+——-+——-+————–+————–+——-+——-+ | 12 | Sending data | 33.764396 | 7.523023 | 40…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… go through the settings and status pretty quickly. Analyzing MySQL‘s workload and data After I’m done with that, I’ll… for microsecond logging and additional information in the slow query log output. The stock MySQL server’s limitation of one-second granularity… have. Sending the report to the client After the slow query log analysis is done, I format all my analysis for sending, add…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
… you were using the vanilla MySQL server, you would see an entry like this in the slow query log: # Time: 111229 3… 20ms 95% of the times and is sending 202 rows and 83.83k of data per query while its also examining 246… use to gather more data about the underlying tables involved and the query execution plan used by MySQL. The end result might…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… time object will be free already. OS Waits are relatively slow, and if you get tens of thousands of OS waits… inside InnoDB 442 mysql tables in use 1, locked 0 MySQL thread id 8079, query id 728899 localhost root Sending data select sql_calc… inside InnoDB 166 mysql tables in use 1, locked 0 MySQL thread id 8078, query id 728898 localhost root Sending data select sql_calc…
