Hi, Seconds behind master works this way. It displays the value based on the difference in the relay log's timestamp and the current timestamp on the slave machine, it is always 0 if you have no relay log events to process. This means that your bottleneck is the IO thread. Also, if you monitor seconds behind master, you will see some fluctuation in it, since when you will have a relay log event to process, the timestamp will most likely have a huge difference, seconds behind master will be adjusted accordingly. After the event is processed, it will be 0 again.
If you want to monitor "real" replication lag, you can use mk-heartbeat. Peter On Sun, 2011-09-04 at 20:33 +0200, Adam PAPAI wrote: > Dear List, > > I have a Master -> [ Slave 1, Slave 2 ] setup for years. > > Last week we've reinstalled the whole setup to: 5.1.58 from: 5.1.54. > > The situation is: > > the master says: (show master status) > > mysql-bin.000087 | 974376716 > > > slave says: (show slave status) > > Master_Log_File: mysql-bin.000087 > Read_Master_Log_Pos: 627246309 > Exec_Master_Log_Pos: 627246309 > Relay_Log_Space: 596009233 > Seconds_Behind_Master: 0 > > In reality, it's NOT 0 seconds! it's delayet more than 10-20 minutes, > some times more than 1 hours. > > Why? Is it a network problem? If i restart the slave, nothing happens. > If I restart the master and the slave, it recognises the "delay" and > start to read the logs again, but a few minutes or hours (or sometimes > days later) it stops again. > > Is it a slave or a master problem? Network problems? What should I do? > > > full outputs below: > > mysql> show master status; > +------------------+----------+--------------+------------------+ > | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | > +------------------+----------+--------------+------------------+ > | mysql-bin.000088 | 8078024 | | | > +------------------+----------+--------------+------------------+ > 1 row in set (0.30 sec) > > mysql> > > > > mysql> show slave status\G > *************************** 1. row *************************** > Slave_IO_State: Waiting for master to send event > Master_Host: 10.3.3.12 > Master_User: root > Master_Port: 3306 > Connect_Retry: 60 > Master_Log_File: mysql-bin.000087 > Read_Master_Log_Pos: 627246309 > Relay_Log_File: tungsten-relay-bin.000213 > Relay_Log_Pos: 541523464 > Relay_Master_Log_File: mysql-bin.000087 > Slave_IO_Running: Yes > Slave_SQL_Running: Yes > Replicate_Do_DB: > Replicate_Ignore_DB: > Replicate_Do_Table: > Replicate_Ignore_Table: > Replicate_Wild_Do_Table: > Replicate_Wild_Ignore_Table: > Last_Errno: 0 > Last_Error: > Skip_Counter: 0 > Exec_Master_Log_Pos: 627246309 > Relay_Log_Space: 596009233 > Until_Condition: None > Until_Log_File: > Until_Log_Pos: 0 > Master_SSL_Allowed: No > Master_SSL_CA_File: > Master_SSL_CA_Path: > Master_SSL_Cert: > Master_SSL_Cipher: > Master_SSL_Key: > Seconds_Behind_Master: 0 > Master_SSL_Verify_Server_Cert: No > Last_IO_Errno: 0 > Last_IO_Error: > Last_SQL_Errno: 0 > Last_SQL_Error: > 1 row in set (0.00 sec) > > Any ideas? > > I have the db under /var/db/mysql > > it shows: > > -rw-rw---- 1 mysql mysql 149765008 Sep 4 18:37 > tungsten-relay-bin.000214 > -rw-rw---- 1 mysql mysql 67 Sep 4 18:38 relay-log.info > -rw-rw---- 1 mysql mysql 73 Sep 4 18:38 master.info > > but the date is: > > [root@tungsten /var/db/mysql]# date > Sun Sep 4 19:11:13 CEST 2011 > > > > And it's delayed 1 hour. No data is transferred to the slave. It says: > Secords behind master 0. > > What the hell is going on here? > > -- > Adam PAPAI > Grapes Communication Kft. > http://www.grapes.hu > E-mail: papai.a...@grapes.hu > Phone: +36 30 33-55-735 (Hungary) > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
