Use celery for dashboards

[carlosms]

This issue is to see if there is any configuration that will allow us to run at most 1 parallel query to gitbase.

From local testing we have detected that disk-intensive gitbase queries will perform better sequentially than in parallel.

[smacker]

For charts currently, we are limit by the number of workers (5). Most probably for 5 concurrent requests, the difference isn't big enough to invest time in it. I would keep this issue in the backlog but wouldn't really put in TODO.

[smacker]

in master it's not 5 anymore but $((2 * $(getconf _NPROCESSORS_ONLN) + 1)).

[smacker]

proper way to fix it is to use celery for dashboards. Then we can control the number of connection from config for sourced-ui (currently we run only 1 celery worker for example) and it would solve #121 as well.

[se7entyse7en]

proper way to fix it is to use celery for dashboards.

I guess this is not trivial to do on our fork without messing up next update of superset, am I wrong? Do you also have any information about development in this direction of using celery for dashboards as well upstream?