From: Ananda Kumar (anandklgmail.com)
Date: Wed Jun 18 2008 - 05:58:54 CDT

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do a show full processlist on the 4th slave and see what process is running.
This will the sql's running which will be the cause of the slowness.

Also u need to check on the INTERNET bandwidth from the current data center
to the other data center.

On 6/18/08, Sagar, Sanjeev <sanjeev.sagarmypointscorp.com> wrote:
>
> Hello All,
>
>
>
> I've 4 slaves of a master. Out of 4, 3 are in same data center and have
> no issues. The fourth one is in another data center and some time that
> slave sql_thread lag behind more then 5000 sec. It's only sql_thread,
> which slow down. All H/W, S/W and my.cnf files are same for all slaves.
>
>
>
> I ran the mysqladmin extended-status in iterative mode and following
> kind of results are there in my log file
>
>
>
> | Variable_name | Value |
>
> +----------------------------+-----------+
>
> | Bytes_received | 2117975 |
>
> | Com_insert | 39 |
>
> | Com_show_slave_status | 4 |
>
> | Com_show_status | 1 |
>
> | Com_update | 49 |
>
> | Connections | 1 |
>
> | Handler_read_key | 49 |
>
> | Handler_read_next | 2 |
>
> | Handler_update | 3629 |
>
> | Key_blocks_not_flushed | 1 |
>
> | Key_blocks_unused | -21 |
>
> | Key_blocks_used | 21 |
>
> | Key_reads | 21 |
>
> | Key_write_requests | 94 |
>
> | Key_writes | 75 |
>
> | Max_used_connections | 1 |
>
> | Questions | 93 |
>
> | Table_locks_immediate | 88 |
>
> | Threads_connected | 1 |
>
> | Threads_created | 1 |
>
> +----------------------------+-----------+
>
>
>
> +----------------------------+-----------+
>
> | Variable_name | Value |
>
> +----------------------------+-----------+
>
> | Bytes_received | 1469626 |
>
> | Bytes_sent | 3837 |
>
> | Com_delete | 2 |
>
> | Com_insert | 143 |
>
> | Com_show_status | 1 |
>
> | Com_update | 1247 |
>
> | Handler_delete | 5 |
>
> | Handler_read_key | 1249 |
>
> | Handler_read_next | 73 |
>
> | Handler_read_rnd | 8379 |
>
> | Handler_update | 9625 |
>
> | Handler_write | 8492 |
>
> | Key_blocks_not_flushed | 1 |
>
> | Key_blocks_unused | -158 |
>
> | Key_blocks_used | 158 |
>
> | Key_read_requests | 52672 |
>
> | Key_reads | 158 |
>
> | Questions | 1394 |
>
> | Table_locks_immediate | 1392 |
>
> | Threads_cached | 1 |
>
> | Threads_connected | -1 |
>
>
>
>
>
>
>
>
>
> Any idea any one, that what can be tunned here for keeping sql_thread
> running same as other slaves. My key_buffers are set to 1G in cnf file.
> Also on this slave, no binary logging is enabled or no slow log is
> enabled. And no application is connected. This is purely stand alone
> slave for disaster recovery.
>
>
>
> Regards,
>
>
>
>
>
>

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