analytics-store was brought down at 6am, and then again at 9am UTC 25 Dec due to multiple executions of long running queries (some of them 2 days long) such as:
SELECT LEFT(timestamp, 8) AS yearmonthday, timestamp, userAgent, clientIp, webHost, COUNT(*) AS copies
FROM log.PageContentSaveComplete ...
SELECT
COUNT(*) AS count,
term_entity_type,
term_type,
term_language
FROM wikidatawiki.wb_terms ...
select date('20161218000000') as day,
actions,
count(*) as repeated
from (select group_concat(event_action order by timestamp, action_order.ord separator '-') as actions
from (select ...
I would urge you to setup a per-user/per-service query resource limits, otherwise poorly performant queries will affect all users (and in cases like this, create downtime). I have set up query limits for all research/analytics users temporarily until 3rd January.