Oracle 5.0 Reference Manual page 1494

Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
The key fields from the status report to examine are:
• Slave_IO_State: The current status of the slave. See
Thread States", and
• Slave_IO_Running: Whether the I/O thread for reading the master's binary log is running.
Normally, you want this to be
stopped it with
STOP
• Slave_SQL_Running: Whether the SQL thread for executing events in the relay log is running. As
with the I/O thread, this should normally be Yes.
• Last_Error: The last error registered when processing the relay log. Ideally this should be blank,
indicating no error.
• Seconds_Behind_Master: The number of seconds that the slave SQL thread is behind processing
the master binary log. A high number (or an increasing one) can indicate that the slave is unable to
handle events from the master in a timely fashion.
A value of 0 for
Seconds_Behind_Master
has caught up with the master, but there are some cases where this is not strictly true. For example,
this can occur if the network connection between master and slave is broken but the slave I/O thread
has not yet noticed this—that is,
It is also possible that transient values for
accurately. When the slave SQL thread has caught up on I/O,
0; but when the slave I/O thread is still queuing up a new event,
show a large value until the SQL thread finishes executing the new event. This is especially likely
when the events have old timestamps; in such cases, if you execute
times in a relatively short period, you may see this value change back and forth repeatedly between
0 and a relatively large value.
Several pairs of fields provide information about the progress of the slave in reading events from the
master binary log and processing them in the relay log:
• (Master_Log_file, Read_Master_Log_Pos): Coordinates in the master binary log indicating
how far the slave I/O thread has read events from that log.
• (Relay_Master_Log_File, Exec_Master_Log_Pos): Coordinates in the master binary log
indicating how far the slave SQL thread has executed events received from that log.
• (Relay_Log_File, Relay_Log_Pos): Coordinates in the slave relay log indicating how far the
slave SQL thread has executed the relay log. These correspond to the preceding coordinates, but
are expressed in slave relay log coordinates rather than master binary log coordinates.
On the master, you can check the status of connected slaves using
the list of running processes. Slave connections have
mysql> SHOW PROCESSLIST \G;
*************************** 4. row ***************************
Id: 10
User: root
Host: slave1:58371
db: NULL
Command: Binlog Dump
Time: 777
State: Has sent all binlog to slave; waiting for binlog to be updated
Info: NULL
Because it is the slave that drives the replication process, very little information is available in this
report.
Common Replication Administration Tasks
Section 8.10.7, "Replication Slave SQL Thread
unless you have not yet started replication or have explicitly
Yes
SLAVE.
slave_net_timeout
Seconds_Behind_Master
1474
Section 8.10.6, "Replication Slave I/O
can usually be interpreted as meaning that the slave
[1466] has not yet elapsed.
Seconds_Behind_Master
Seconds_Behind_Master
SHOW PROCESSLIST
in the
Binlog Dump
States", for more information.
may not reflect the situation
SHOW SLAVE STATUS
to examine
field:
Command
displays
may
several