Bug #85965 Expose, on the master, counters for monitoring parallel information quality.
Submitted: 16 Apr 22:11 Modified: 11 May 10:03
Reporter: Jean-François Gagné Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: Replication Severity:S4 (Feature request)
Version:5.7 and 8.0 OS:Any
Assigned to:
Triage: Needs Triage: D5 (Feature request)

[16 Apr 22:11] Jean-François Gagné
Description:
Hi,

in [1], I present a metric for tuning parallel replication: the "Average Modified Interval Length".  For computing this metric, the binary logs needs to be parsed, which is a hurdle.  This feature request is about exposing some global statuses for easing computing this metric (only looking at MySQL).

[1]: http://jfg-mysql.blogspot.com/2017/02/metric-for-tuning-parallel-replication-mysql-5-7.htm...

The Average Modified Interval Length" needs the following global statues to be computed:

-BINLOG_COMMIT: counts the number of transactions written to the binary logs,

-BINLOG_INTERVAL_LENGTH_MODIFIED_MYSQL_5_7_19: accumulates (sums) the "modified" interval length (I am using MYSQL_5_7_19 as a suffix for this metric because the MTS applier might be changed and a new "modified" counter might be needed as we need to be able to expose the metric for a MySQL 5.7.19 slave and for other future versions or MySQL, including 5.7.x and 8.x.y).

More details in [1] above.

In addition to the global statuses above, the global statuses below could also be implemented for completeness:

-BINLOG_INTERVAL_LENGTH: accumulates (sums) the unmodified interval length,

-BINLOG_INTERVAL_LENGTH_SQUARE: accumulates (sums) the square of the unmodified interval length (for computing a standard deviation),

-BINLOG_INTERVAL_LENGTH_MODIFIED_MYSQL_5_7_19_SQUARE: would accumulate (sum) the square of the "modified" interval length.

Many thanks,

JFG

How to repeat:
Not a bug but a feature request.

Suggested fix:
Implement new global statuses.
[18 Apr 12:14] Umesh Shastry
Hello Jean,

Thank you for the feature request!

Thanks,
Umesh
[11 May 10:03] Jean-François Gagné
Change from MySQL Cluster to MySQL Server.