…bug: http://bugs.mysql.com/bug.php?id=67647 Metadata locking behaves differently for queries… | id | x | +—-+——+ | 1 | foo | | 2 | bar | +—-+——+ 2 rows in set (0.00 sec) session3 > show processlist; …
Post: PHP Large result sets and summary tables.
July 6, 2007 By 8 Comments
… can’t use mysql_num_rows() and mysql_data_seek() if you use this method but this is told in PHP manual and so… SQL_BUFFER_RESULT hint if you need to release table locks early. It comes at cost of creating temporary table though… call you can get errors is when you run mysql_query , mysql_fetch_row simply reads data from memory and so most applications…
Post: PHP Sessions - Files vs Database Based
March 27, 2007 By 38 Comments
…our customers. If you use file based sessions PHP will lock session file for whole script execution duration…or lock tables. So how you can get back your old file based session behavior with MySQL Sessions … and use SELECT … FOR UPDATE to lock the session row in the session table for whole request…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…mysql> show table status like ‘ontime_fact’G *************************** 1. row *************************** Name: ontime_fact Engine: InnoDB Version: 10 Row_format: Compact Rows: 6697533 Avg_row…to your number of nodes) php genconfig 20 > shards.ini… innodb-stats-update-need-lock=0 innodb-status-file …
Comment: How much memory Innodb locks really take ?
May 19, 2012 By 11 Comments
… VB6 to PhP/MySQL/Apache/InnoDB. Do you think you can show a program where row-locks are used by one user to lock records…
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
… Innodb tables do internal full table > lock if auto_increment is used… background. > Things are different with MySQL. Good design will help dictate…use the indexes to join rows together, potentially preventing a table …> to crawl. > So developing you PHP applications use test database with reasonable…
Comment: INSERT ON DUPLICATE KEY UPDATE and summary counters.
March 23, 2012 By 48 Comments
….mysql.com/bug.php?id=52020 Can you please explain how really locking in INSERT … ON DUPLICATE KEY UPDATE works. As I recall: Lock…) Lock 3) Transaction 1 tries to locks row for UPDATE (goes into queue) It is reasonable not to release Lock 1, but why MySQL tries to create Lock 3…
Comment: MySQL Query Cache WhiteSpace and comments
March 25, 2008 By 9 Comments
My understanding is that the mysql command line client now has an *option* to pass comments … server, but it’s disabled by default: http://bugs.mysql.com/bug.php?id=26215 I’m running the 5.0.56… # User@Host: dbadmin[dbadmin] @ localhost [] # Query_time: 2 Lock_time: 0 Rows_sent: 230400 Rows_examined: 480 select /* my comment */ * from test.WEBSITE…
Post: On Good Instrumentation
May 31, 2010 By 1 Comment
… example I’d like to see number of mysql calls in addition to MySQL response time. This helps to understand if it… query from PHP application side, but we can’t say why it has taken so long. Was it row level lock ? waiting on…. I see response time is coming from MySQL. I check the number of MySQL Queries and it is 5x when it usually…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
… changes in later 5.0 series compact row format was implemented which can help performance (…only recently found and fixed: http://bugs.mysql.com/bug.php?id=29560 Concerning a switch to … should be possible to implement online reorganize which locks and reorganizes small portions of table online. Q38…
