Query switch along with index pattern doesn't work in Discover

[marcinpm]

Kibana version: 6.2.4, 6.3.0 and 6.4.2

Elasticsearch version: same as Kibana

Server OS version: tested in Cloud deployment and Centos 6.9

Browser version: Chrome 69.0.3497.100

Browser OS version: Windows 10

Original install method (e.g. download page, yum, from source, etc.): Cloud deployment and yum

Describe the bug:

Kibana Discover for some reasons keeps in memory the running query while you switch the index pattern and submit a new query, then it will provide you with results for the previous query (which should be discarded) but for the switched (new) index pattern. This won't be noticed for queries which return results (end) immediately, however for long running queries it can be bothersome.

Steps to reproduce:

For this reproduction scenario you need to pick a query which takes a moment before displaying any results:

1. In Discover search bar submit a query , let's call it search1 within index pattern (pattern1)
2. While the above search is ongoing, switch to another index pattern (pattern2) from the drop down list.
3. Submit a new querysearch2
4. You will get results from search1 but for the current index pattern (pattern2)

Expected behavior:

As soon as you supply a new search for the new index pattern, it should cancel the previous one, and only provide the result for the new input.

Any additional context:

This was working as expected in Kibana 5.6.X

[marcinpm]

@Bargs FYI

[Bargs]

Based on the description I'm fairly certain this is caused by the same underlying problem described in #17844 (and related to all the other issues linked there).

[timroes]

I am agreeing with Matt here. This seems to be caused by querying not being canceled properly, so I would close this in favor of #17844