Wait for POC of Elastic Search - Round estimated search result hit count (totalRecords)

CW: This feature is in an undecided state, due to awaiting the outcome of the POC of using Elastic Search in Inventory. 

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Purpose:

The totalRecords search result hit count number returned by RMB is precise if totalRecords is below 1000 and it is only an estimation if totalRecords >= 1000 (details).
The front-end currently displays "8081 records found" for estimations.
This is misleading (false precision).

"about" should be prepended for >= 1000.

The number should be rounded for >= 1000.

Scenarios:

1. Scenario
   • Given a result count is estimated (current understanding is that result counts above 1,000 are estimates)
   • When displayed in FOLIO
   • Then:
     • Result count should be preceded by "about"
     • Result count should be rounded using the "Rounded to first digit" method
     • For example:
       • Estimated result count from Postgres = 32351
       • Displays in FOLIO as "about 30,000 records found"
2. Scenario
   • Given a result count is NOT estimated (current understanding is that result counts under 1,000 are exact)
   • When displayed in FOLIO
   • Then:
     • Result count should NOT be preceded by "about"
     • Result count should NOT be rounded
     • For example:
       • Exact result count from Postgres = 845
       • Displays in FOLIO as "845 records found"

Algorithm for the front-end:

if totalRecordsEstimated is true
  print "about " + totalRecordsRounded
else if totalRecordsEstimated is false
  print totalRecords
// totalRecordsEstimated is undefined until all back-ends have upgraded RMB,
// handle this gracefully for folio-testing:
else if totalRecords < 1000
  print totalRecords
else
  print "about " + totalRecords + " (upgrade back-end for rounding)"

Background Discussion:

• Three rounding proposals were considered
• Option B, "Round to first digit" was selected

Details on Rounding Options Considered:

3 rounding proposals are in the comments of MODINVSTOR-468:

A) Round to magnitude:

B) Round to first digit:

C) Round first digit to 1, 2 or 5:

This issue is about deciding whether there should be a FOLIO standard for rounding, and if yes, which to choose, and whether the front-end or the back-end should round the number.

Proposed API as of July 28, 2020

If the back-end rounds it should also provide to original (non-rounded) estimate, for example

totalRecords: 1431
totalRecordsRounded: 1000
totalRecordsEstimated: true

No rounding is needed for an exact number:

totalRecords: 1509
totalRecordsEstimated: false

https://github.com/folio-org/raml/blob/raml1.0/schemas/resultInfo.schema needs to be extended accordingly.