… The query inside the procedure gets logged …Query thread_id=15 exec_time=0 error_code=0 SET TIMESTAMP=1323817490/*!*/; INSERT INTO y (value) VALUES(LAST… insert into y (i,value) VALUES(4…in account when we are working with statement based replication. Knowing in advances how MySQL works internally can…
Post: Statement based replication with Stored Functions, Triggers and Events
December 16, 2011 By 4 Comments
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…how you need to query the data. It is a hard question to answer, and sometimes I‘ve seen it evolve over time…get there, it can change the lifecycle of your application in advance. What about partitioning in MySQL 5.1? I…
Post: Quickly finding unused indexes (and estimating their size)
December 5, 2012 By 2 Comments
…I want to consider dropping indexes in). Let’s keep using views so this dynamically updates as our schema changes over time: mysql…i.index_name; Now I can query this view to see my indexes: mysql…last_name NON_UNIQUE: 1 COLUMN_CNT: 1 COLUMN_NAMES: last_name 1 row in set (0.03 sec) Now I…
Post: The four fundamental performance metrics
April 27, 2011 By 15 Comments
…MySQL. In the best case, we want to know everything about the system’s activity: we want to know how many things happened, how…queries in the interval. The total time during which queries resided in the system — the “busy time.” The total execution time of all queries — the “weighted time.” We can…
Post: The two even more fundamental performance metrics
May 5, 2011 By 6 Comments
…time is under a millisecond — maybe it’s 50 microseconds, maybe a bit longer. This is common in MySQL servers I…in tenths of a second, I get the following plot: That’s getting pretty crowded, but just trust me when I say that you can…
Post: Can MySQL temporary tables be made safe for statement-based replication?
May 26, 2008 By 8 Comments
…in MySQL 5.1 and later, but most installations I know of are using statement-based replication, even on MySQL…Last_Errno: 1146 Last_Error: Error ‘Table ‘test.t’ doesn’t exist’ on query. Default database: ”. Query…
Post: Replaying database load with Percona Playback
October 25, 2012 By 9 Comments
…can measure how a database upgrade, change on my.cnf or schema change can affect the overall performance of your application. In the example I…time to get valuable information: SET GLOBAL slow_query_log=1; SET GLOBAL long_query_time=0; With long_query_time we are logging all queries…
Post: MySQL: Followup on UNION for query optimization, Query profiling
August 14, 2006 By 14 Comments
…how counters have changed. It was quite inconvenient you could only do it on idle box so as in MySQL…can handle what IN can‘t: Lets say we want to show people in appropriate age group sorting by time when they were last…
Post: Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By 3 Comments
…in time recovery) in case of that ‘Oops’ moment? Let me show you quickly how…I can have an angry mob of employees who may not get their salaries on time!). mysql> delete from salaries where emp_no = 10001; Query…
Post: The story of one MySQL Upgrade
October 8, 2010 By 8 Comments
…in MySQL 5.0. There are number of ways the problem can be solved but first we decide to see how…query time differences. In most cases query time differences were not significant or Percona Server 5.1 did better but there were couple of queries…
