Large number of frequent updates on the "projects" table

Per our tuple statistics (https://performance.gitlab.net/dashboard/db/postgres-tuple-statistics?refresh=1m&orgId=1) we seem to be updating projects quite a lot over time:

Screenshot_from_2017-11-17_17-49-12

This in turn also affects the number of dead tuples over time:

Screenshot_from_2017-11-17_17-51-16

Looking at the last 90 days of data we can see the number of dead tuples per minute gradually increase:

Screenshot_from_2017-11-17_17-52-46

I'm worried that some process is performing unnecessary updates on the projects table. We should reduce this value back to the old value of <= 5k dead tuples per minute, instead of 17k.

cc @tiagonbotelho