Hi Sean,

Here's Marcel from Analytics.

I'd like to comment with you some strange behaviors that we've observed on EventLogging database (m4-master.equiad.wmnet).

1) There are some time spans where there is no data in any table. Examples follow:

2015-04-09 17:20 -> 18:35
2015-04-11 03:35 -> 05:20
2015-04-11 14:00 -> 15:20
2015-04-11 19:00 -> 20:00
2015-04-12 14:30 -> 15:40
2015-04-13 11:35 -> 12:30
2015-04-13 16:30 -> 17:35

This is happening a lot, as you can see, so we are really concerned about it.

These outages are not explained by any of the EventLogging logs (processor logs, consumer logs) which confirm that the events were actually sent normally to the database (and written) for those time spans.

2) Maybe it has something to do with it, or not. But we observed that sometimes the last events inserted in the tables date from 30mins - 1h30mins in the past. At other moments, the last inserts date from seconds ago. This is maybe expected due to slave replication but we're not sure.

Do you have some opinion on what can be happening? Any thought would help a lot.

Thanks!

Marcel