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.