connection for page-data fetch requests in query o demand gets closed sometimes

[pieh]

Occasionally some requests seem to get a lot of added latency and the socket gets closed:

This needs more investigation, but initial running theory is that query running takes longer than 5 seconds which is default timeout of Node.js server before it close the socket connection ( https://nodejs.org/docs/latest-v8.x/api/http.html#http_server_keepalivetimeout ) - note that this doesn't break the fetch request per se - it does fallback to different methods and will eventually deliver response (this is lower level than http requests themselves), but this seems to add quite a noticeable latency on top of query running alone.

We can either bump keepAliveTimeout globally for express server or target just the page-data express handler ( expressjs/express#3556 ). But due to https://docs.pushtechnology.com/cloud/latest/manual/html/designguide/solution/support/connection_limitations.html it might not be as straight forward and cause different issues.