Large number of options in Multi Select Custom Field hangs browser in Issue Navigator

Summary

This issue has the same context and root cause as JRASERVER-44588 : Multi Select Custom Field loads options in a suboptimal way, but describes a different performance implication. JRASERVER-44588 discusses REST and DB performance on the JIRA server backend. This describes browser frontend performance.

When adding a Multi Select Custom Field with very many options (at least 1000, but performance implications are more visible at larger numbers, such as 10,000) to the Basic Search functionality in JIRA's Issue Navigator, the Issue Navigator screen will become unresponsive for a significant period of time before returning control to the user. Attempting to click the custom field in question to expand it's dropdown will also trigger a period of unresponsiveness.

Environment

Performance appears to be worse in Google Chrome rather than Firefox, with Chrome experiencing unresponsiveness approximately 1.5 - 2x longer than Firefox does. (~8 seconds in Chrome vs ~5 seconds in Firefox in a fresh environment with a Multi Select Custom Field with 10,000 options)

Steps to Reproduce

1. Create a new Select List (multiple choice) custom field
2. Add at least 1000 options, but recommended 10000 options to the field
3. Navigate to the Issue Navigator in Basic Search
4. Add said custom field to the Basic Search filter

Expected Results

The custom field in question is added to the Basic Search criteria with no browser unresponsiveness

Actual Results

The Issue Navigator will become unresponsive, with the duration depending on the number of options being loaded and the performance of the browser's physical machine.

See JRASERVER-66085.mp4 for a demonstration of unresponsiveness in Google Chrome, along with Chrome's Performance Profiler results.

Workaround

• Use Firefox for somewhat improved responsiveness.

• Use Advanced Search and JQL to search instead.
  • In JQL, after typing the custom field name and standing by for suggested results to populate, the browser will not freeze, but will still be processing the options. If given enough time, the suggested results will appear. At this time, these results will be cached and will be readily available for further searching until the cache expires or is refreshed.