fix(metrics): differentiate points in different minutes to be more accurate (#2770)

lib/commands/includes/collectMetrics.lua

@@ -19,7 +19,7 @@ local function collectMetrics(metaKey, dataPointsList, maxDataPoints, timestamp)
         return
     end
 
-    local N = math.min(math.floor((timestamp - prevTS) / 60000), tonumber(maxDataPoints))
+    local N = math.min(math.floor(timestamp / 60000) - math.floor(prevTS / 60000), tonumber(maxDataPoints))
 
     if N > 0 then
         local delta = count - rcall("HGET", metaKey, "prevCount")

test/test_metrics.js

@@ -34,6 +34,8 @@ describe('metrics', () => {
       ONE_MINUTE,
       ONE_MINUTE,
       ONE_MINUTE * 3,
+      ONE_SECOND * 70,
+      ONE_SECOND * 50,
       ONE_HOUR,
       ONE_MINUTE
     ];
@@ -100,6 +102,8 @@ describe('metrics', () => {
       '0',
       '0',
       '1',
+      '1',
+      '1',
       '0',
       '0',
       '1',