[JIRAALIGN-1376] Portfolio Room - Theme Burnup Chart takes a long time to load or fails to load completely

Issue Summary

On some customer instances, the Theme Burnup Chart takes 20 seconds or more to load or fails to load completely. In cases where the burnup chart fails to load at all, we notice a sql query timeout on the backend similar to below (customer information has been redacted, but, the error signatures are identical). The timeout points to the RPM_GET_STORY_POINTS_TREND_FOR_RELEASE stored procedure:

{ [-]
   ASP_function: OOFunctionsSql.SetRSParamsCursor
   correlationid: yGtu3lkinnEDvfre8zy3owG5vAeCUbHMUxmhHjuH2SU=
   customer_db: XXXXXX
   error_description: Query timeout expired
   error_id: 20796
   error_number: -2147217871
   error_source: Microsoft SQL Server Native Client 11.0
   log_type: exception
   logfrom_location: Website-ASP
   sql: EXEC RPM_GET_STORY_POINTS_TREND_FOR_RELEASE '99', NULL, NULL, NULL, NULL, NULL, '575'
   timestamp: 2020-04-15T09:47:51.059000-04:00
   url: https://XXXX.agilecraft.com:443/AjaxFiles/AjaxPortfolioRoom.asp?ActionType=17&themeID=575
   urlverb: GET
   user: 3573
   version: 10.68.0.3964
}

For an example of slow loading times, this can be demonstrated on sabenw.agilecraft.com using the steps below:

Steps to Reproduce

1. Log in to sabenw.agilecraft.com
2. In Tier 1 enter Mission - Digital Services Quarterly Increment - QI-5
3. Navigate to the "Missions Room" (Portfolios have been renamed to "Misisons" in this instance)

Expected Results

Theme Burnup Chart should load quickly (i.e. in less than 10 seconds)

Actual Results

The Theme Burnup Chart takes up to 20 seconds or more to load, OR, in some customer cases, it never loads and we end up with the query timeout described above.

Workaround

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