…how to use this info to improve MySQL Performance. To…count” and “signal count” show how actively innodb uses internal sync array – how frequently slots are allocated in it and how…variable. Value is specified in microseconds. mysql tables in use 1, locked 0 is number of tables used by transaction in…
Post: ANALYZE: MyISAM vs Innodb
September 3, 2008 By 9 Comments
…to find number of exact values in the table. Now let us populate antest_innodb table which is same but uses Innodb format: mysql…
Post: SQL Injection Questions Followup
July 26, 2012 By 2 Comments
…to create IN predicates. But you can add a variable number of parameter placeholders based on the length of the array of values in…how to escape input that contains non-printing characters. The standard API function mysql…
Post: Timezone and pt-table-checksum
September 25, 2012 By 1 Comment
…MySQL is storing these values in…variable to our advantage. If both servers were set up using UTC as the timezone (which is the recommended practice – store everything in…COUNT…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
…to run their queries. Stored Procedures – How much memory can stored procedure allocate ? say can you create 1000 variables in stored procedure and set 1M result set to…count are designed to protect from typical application mistakes not from someone intentionally trying to bring MySQL…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
…to enable logging atomically, not just for new connections as in MySQL…Count of number of times this query was executed. Now let’s take a look at the values in…
Post: Innodb row size limitation
April 7, 2011 By 12 Comments
…counting other fixed length columns. This exceeds the limit and therefore you get the error. You don’t have to…variable length field, it doesn’t mean you need to be able to store data up to that fields’ maximum allowed value…to your application if you choose XML as format and you use MySQL‘s built in…
Post: Joining on range? Wrong!
May 17, 2010 By 10 Comments
…to serve our purpose. Our hypothetical sales query could be to figure out how many LCD TVs were sold yesterday. SELECT COUNT…in joins. Let’s verify how the query performed in greater detail: SHOW STATUS LIKE ‘Handler_read%’; +———————–+——–+ | Variable_name | Value…
Post: MySQL Server Memory Usage
May 17, 2006 By 21 Comments
…how should they estimate memory consumption by MySQL Server in given configuration. What is the formula they could use. The reasons to…in practice and how memory consumption reacts to changing various variables. For example you may find out increasing sort_buffer_size from 1MB to…
Post: Debugging problems with row based replication
May 6, 2010 By 12 Comments
…In fact, the default binary logging format in GA versions of MySQL 5.1 is ‘MIXED’ STATEMENT*; The binlog_format variable…MySQL slaves to prevent accidental changes in data from happening! *edit* The MySQL 5.1 default binary logging format changed back to STATEMENT in MySQL…
