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From:Rick James Date:April 2 2012 9:44pm
Subject:Re: Seconds Behind Master increasing in slave
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* If the Slave is less powerful than the Master (eg no RAID vs RAID), 
hardware can contribute to the long delays.
* If the queries on the Master are done in parallel,...  Replication 
serializes the queries, thereby taking more elapsed time on the Slave.  
(Note:  There is only one Update running on the slave, no matter how 
many are queued up.)

On 4/2/12 1:58 PM, Arthur Fuller wrote:
> The immediate  suspect is that single update statement. Is it a massive
> batch-update? If so, is it possible to break it down into several smaller
> updates, run successively?
>
> Arthur
>
> On Mon, Apr 2, 2012 at 4:26 PM, David Lerer<DLerer@stripped>  wrote:
>
>> How long did the one update statement run?
>> (A slow update, even if it is a single transaction, can slow down
>> replication.
>> David.
>>
>> -----Original Message-----
>> From: Revathi Rangachari [mailto:masrrev@stripped]
>> Sent: Monday, April 02, 2012 3:42 PM
>> To: replication@stripped
>> Subject: Seconds Behind Master increasing in slave
>>
>> Hi
>>
>> We have a master-slave setup.  The slave acts only as a replicate and does
>> not cater to any client requests.
>>
>> Over the last 24 hours there has been more than 4 to 6 hours delay in the
>> replication.  The CPU, IO, memory usage all seem to be under control.  I
>> changed the  SET GLOBAL innodb_flush_log_at_trx_commit = 0 ;
>>
>> The slave sql and io threads are running.
>> show processlist shows only one update statement on a table.
>>
>> In spite of all this the slave still lags behind in replication by 5 hours.
>>
>> Any suggestion to improve the replication performance is highly
>> appreciated.
>>
>> Thanks
>> Revathi R
>>
>>

-- 
Rick James - MySQL Geek

Thread
adding another slavenhadie ramos1 Apr
  • Re: adding another slavea.smith1 Apr
  • Re: adding another slaveNeil Armitage1 Apr
    • Re: adding another slavenhadie ramos1 Apr
      • Seconds Behind Master increasing in slaveRevathi Rangachari2 Apr
        • RE: Seconds Behind Master increasing in slaveDavid Lerer2 Apr
          • Re: Seconds Behind Master increasing in slaveArthur Fuller2 Apr
            • Re: Seconds Behind Master increasing in slaveRick James2 Apr
              • Re: Seconds Behind Master increasing in slaveRevathi Rangachari2 Apr
                • Re: Seconds Behind Master increasing in slavePankaj Joshi3 Apr
            • Re: Seconds Behind Master increasing in slaveRevathi Rangachari2 Apr
              • Re: Seconds Behind Master increasing in slavenehal dattani2 Apr
                • Re: Seconds Behind Master increasing in slaveRevathi Rangachari2 Apr
          • RE: Seconds Behind Master increasing in slaveRevathi Rangachari2 Apr