Issue Summary

When searching for issues using the "Parent Link" JQL clause, the UI timeouts:

Steps to Reproduce

1. Go to the advanced issue search.
2. Switch to JQL search
3. Use one of the following filters:
   1. "Parent Link" is NOT EMPTY
   2. "Parent Link" is EMPTY
4. You will notice that search is timing out after 30 seconds with error on UI ("An unknown error occurred while trying to perform a search."*)

Expected Results

The search should come with a result, independently of the amount of issues you have.

Actual Results

The below exception is thrown in the console

{"errorMessages":["jqlTooComplex"],"errors":{}}
{"errorMessages":["An unknown error occurred while trying to perform a search."],"errors":{}} 

Workaround

Currently there is no known workaround for this behaviour. A workaround will be added here when available