Re: purge thread
Hi Geetanjali, Well word of caution with this setting, it can block the whole server if the purge thread is delayed too much. Also look into other things like IO saturation or issues with disk as to why the purge thread is not able to keep up with the backlog. If IO is not the issue then there is a very old read view, which might be blocking the purge thread, so long running transactions not recommended. We have seen situations where a bad disk had caused huge History_length. Cheers!!! Akshay On Tue, Sep 2, 2014 at 12:27 PM, geetanjali mehra mailtogeetanj...@gmail.com wrote: Could you please put some more light on it? Best Regards, Geetanjali Mehra Senior Oracle and MySQL DBA Corporate Trainer and Database Security Specialist On Thu, Aug 28, 2014 at 2:09 AM, shawn l.green shawn.l.gr...@oracle.com wrote: Hello Geetanjali, On 8/26/2014 1:16 AM, geetanjali mehra wrote: I want to understand how to tune innodb_max_purge_lag http://dev.mysql.com/doc/refman/5.5/en/innodb- parameters.html#sysvar_innodb_max_purge_lag when history list length is high. Could anyone explain me. Best Regards, Geetanjali Mehra Senior Oracle and MySQL DBA Corporate Trainer and Database Security Specialist This setting not related to the history value. It is there to help control the gap between these two values of the InnoDB status report Trx id counter 0 290328385 Purge done for trx's n:o 0 290315608 undo n:o 0 17 What is the current transaction compared what is the oldest transaction that still has aged copies of data left in the data area of the tablespace. The difference between those two values is the purge backlog Yours, -- Shawn Green MySQL Senior Principal Technical Support Engineer Oracle USA, Inc. - Hardware and Software, Engineered to Work Together. Office: Blountville, TN -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: purge thread
Could you please put some more light on it? Best Regards, Geetanjali Mehra Senior Oracle and MySQL DBA Corporate Trainer and Database Security Specialist On Thu, Aug 28, 2014 at 2:09 AM, shawn l.green shawn.l.gr...@oracle.com wrote: Hello Geetanjali, On 8/26/2014 1:16 AM, geetanjali mehra wrote: I want to understand how to tune innodb_max_purge_lag http://dev.mysql.com/doc/refman/5.5/en/innodb- parameters.html#sysvar_innodb_max_purge_lag when history list length is high. Could anyone explain me. Best Regards, Geetanjali Mehra Senior Oracle and MySQL DBA Corporate Trainer and Database Security Specialist This setting not related to the history value. It is there to help control the gap between these two values of the InnoDB status report Trx id counter 0 290328385 Purge done for trx's n:o 0 290315608 undo n:o 0 17 What is the current transaction compared what is the oldest transaction that still has aged copies of data left in the data area of the tablespace. The difference between those two values is the purge backlog Yours, -- Shawn Green MySQL Senior Principal Technical Support Engineer Oracle USA, Inc. - Hardware and Software, Engineered to Work Together. Office: Blountville, TN -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: purge thread
Hello Geetanjali, On 8/26/2014 1:16 AM, geetanjali mehra wrote: I want to understand how to tune innodb_max_purge_lag http://dev.mysql.com/doc/refman/5.5/en/innodb-parameters.html#sysvar_innodb_max_purge_lag when history list length is high. Could anyone explain me. Best Regards, Geetanjali Mehra Senior Oracle and MySQL DBA Corporate Trainer and Database Security Specialist This setting not related to the history value. It is there to help control the gap between these two values of the InnoDB status report Trx id counter 0 290328385 Purge done for trx's n:o 0 290315608 undo n:o 0 17 What is the current transaction compared what is the oldest transaction that still has aged copies of data left in the data area of the tablespace. The difference between those two values is the purge backlog Yours, -- Shawn Green MySQL Senior Principal Technical Support Engineer Oracle USA, Inc. - Hardware and Software, Engineered to Work Together. Office: Blountville, TN -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
purge thread
I want to understand how to tune innodb_max_purge_lag http://dev.mysql.com/doc/refman/5.5/en/innodb-parameters.html#sysvar_innodb_max_purge_lag when history list length is high. Could anyone explain me. Best Regards, Geetanjali Mehra Senior Oracle and MySQL DBA Corporate Trainer and Database Security Specialist
