On 10/28/2011 3:38 PM, jiangwen jiang wrote:
Hi, all:I am confusing with seconds_behind_master, in mysql manual, it says: In essence, this field measures the time difference in seconds between the slave SQL thread and the slave I/O thread. how to understand this description: 1. seconds_behinds_master = ts in SQL thread - ts in I/O thread, or seconds_behinds_mater = ts in I/O thread - ts in SQL thead 2. how to get the timestamp in SQL and I/O thread, when this time will update? Thanks W.J
According to <High performance mysql>, seconds_behinds_master is inaccurate, so I just skipped how it works... If you want to measure slave lag, follow that book's suggestion: One good solution is a heartbeat record,which is a timestamp that you update once persecond on the master.To calculate the lag,you can simply subtract the heartbeat from the current timestamp on the slave. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
