[Engineering] Eventlogging Mysql consumers downtime

Wed Jan 20 21:08:24 UTC 2016

Hi all,

In order to convert tables on db1046 to the TokuDB engine - we have to
schedule some downtime on the Eventlogging databases between tomorrow,
Thursday Jan 21, 2016 at 16:00 UTC to Monday Jan 25, 2016 16:00 UTC.

What this means for EL users:

1. Eventlogging will still receive data and it will be available in Kafka.
The data will continue to be imported into Hadoop and files.
2. The Mysql consumers of Eventlogging will be stopped, so no data will get
imported into the master(db1046 or m4-master) and by extension to the
analytics-store.
3. Querying existing data from analytics-store will still be available, but
data for the next 4 days won't be available.
4. On Monday, after the maintenance window we'll restart the Mysql
consumers, and all the data should get reimported from Kafka.

Analytics and Ops(DBA) will work on this together.

Feel free to reach out to us here or on #wikimedia-analytics if you have
any concerns/questions.

-- Madhu Viswanathan
Software Engineer, Analytics
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