maria-developers team mailing list archive

[Sachin Setiya <sachin.setiya@xxxxxxxxxxx>]

Hi Kristian!

On Tue, Jan 10, 2017 at 5:37 PM, Kristian Nielsen <knielsen@xxxxxxxxxxxxxxx>
wrote:
> Sachin Setiya <sachin.setiya@xxxxxxxxxxx> writes:
>
>> Okay, So it there a better way to show progress in slave ?
>
> You have not explained what you mean by "showing progress".
>
> Doesn't SHOW SLAVE STATUS already show event-by-event progress in the
relay
> log position?
>
> For progress inside a row event, for example one could display the offset
of
> current row operation as a percentage of total event size. Be sure to
> consider the performance impact of such status updates.
>
> Why does replication slave need different progress monitoring than any
other
> thread doing queriess?
>
> I mean, more visibility and monitoring is nice, sure. But it should start
> with a general approach and design. Not by randomly adding bits and pieces
> to various binlog events (or other places) without a clear idea what is
> being achieved, and why...
>
>  - Kristian.
This task is related to mdev-7409 / mdev-4557.
I have created a patch for this mdev. but I was thinking for monitoring
command 'SHOW PROCESSLIST'
in Progress column can we show how much % of the events from Event group
Slave has applied so that
user can get a better monitoring.
If I apply my patch I get only this.
MariaDB [d]> show processlist;
+----+-------------+-----------+------+---------+------+-------------------------------------------------+------------------+----------+
| Id | User        | Host      | db   | Command | Time | State
                              | Info             | Progress |
+----+-------------+-----------+------+---------+------+-------------------------------------------------+------------------+----------+
|  3 | system user |           | d    | Connect |    0 |
Write_rows_log_event::write_row(-1) on table t1 | NULL             |
 0.000 |
|  4 | system user |           | NULL | Connect |  121 | Waiting for master
to send event                | NULL             |    0.000 |
|  7 | root        | localhost | d    | Query   |    0 | init
                             | show processlist |    0.000 |
+----+-------------+-----------+------+---------+------+-------------------------------------------------+------------------+----------+

Progress is always zero.
So I was thinking if somehow in advace we can know how many events are
there in event group we can show progress to
user by calculating how much % of events from Event group we have executed.
Regards
sachin