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From:Ananda Kumar Date:June 18 2008 10:58am
Subject:Re: slave is running slow in another data center
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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.sagar@stripped> 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,
>
>
>
>
>
>

Thread
slave is running slow in another data centerSanjeev Sagar18 Jun
  • Re: slave is running slow in another data centerAnanda Kumar18 Jun
    • RE: slave is running slow in another data centerSanjeev Sagar18 Jun
      • Re: slave is running slow in another data centerAnanda Kumar19 Jun