lib/logstorage: properly skip filtered out dict values when calculating uniq_values, min, max, row_min and row_max stats functions

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7458

docs/VictoriaLogs/CHANGELOG.md

@@ -26,6 +26,7 @@ according to [these docs](https://docs.victoriametrics.com/victorialogs/quicksta
 * FEATURE: [Loki data ingestion](https://docs.victoriametrics.com/victorialogs/data-ingestion/#loki-json-api): show the original request body on parse errors. This should simplify debugging. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7490).
 
 * BUGFIX: [`values` stats function](https://docs.victoriametrics.com/victorialogs/logsql/#values-stats): fix a bug, which could lead to corrupted results. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7458).
+* BUGFIX: [`uniq_values`](https://docs.victoriametrics.com/victorialogs/logsql/#uniq_values-stats), [`min`](https://docs.victoriametrics.com/victorialogs/logsql/#min-stats), [`max`](https://docs.victoriametrics.com/victorialogs/logsql/#max-stats), [`row_min`](https://docs.victoriametrics.com/victorialogs/logsql/#row_min-stats) and [`row_max`](https://docs.victoriametrics.com/victorialogs/logsql/#row_max-stats) stats functions: fix a bug, which could return non-matching field values for these functions. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7458).
 * BUGFIX: [HTTP querying APIs](https://docs.victoriametrics.com/victorialogs/querying/#http-api): properly take into account the `end` query arg when calculating time range for [`_time:duration` filter](https://docs.victoriametrics.com/victorialogs/logsql/#time-filter). Previously the `_time:duration` filter was treated as `_time:[now-duration, now)`, while it should be treated as `_time:[end-duration, end)`.
 
 ## [v0.41.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v0.41.0-victorialogs)

lib/logstorage/block_result.go

@@ -1726,7 +1726,9 @@ func (c *blockResultColumn) getValuesEncoded(br *blockResult) []string {
 	return c.valuesEncoded
 }
 
-// forEachDictValue calls f for every value in the column dictionary.
+// forEachDictValue calls f for every matching value in the column dictionary.
+//
+// It properly skips non-matching dict values.
 func (c *blockResultColumn) forEachDictValue(br *blockResult, f func(v string)) {
 	if c.valueType != valueTypeDict {
 		logger.Panicf("BUG: unexpected column valueType=%d; want %d", c.valueType, valueTypeDict)
@@ -1756,7 +1758,9 @@ func (c *blockResultColumn) forEachDictValue(br *blockResult, f func(v string))
 	encoding.PutUint64s(a)
 }
 
-// forEachDictValueWithHits calls f for every value in the column dictionary.
+// forEachDictValueWithHits calls f for every matching value in the column dictionary.
+//
+// It properly skips non-matching dict values.
 //
 // hits is the number of rows with the given value v in the column.
 func (c *blockResultColumn) forEachDictValueWithHits(br *blockResult, f func(v string, hits uint64)) {

lib/logstorage/stats_max.go

@@ -114,9 +114,9 @@ func (smp *statsMaxProcessor) updateStateForColumn(br *blockResult, c *blockResu
 			smp.updateStateString(v)
 		}
 	case valueTypeDict:
-		for _, v := range c.dictValues {
+		c.forEachDictValue(br, func(v string) {
 			smp.updateStateString(v)
-		}
+		})
 	case valueTypeUint8, valueTypeUint16, valueTypeUint32, valueTypeUint64:
 		bb := bbPool.Get()
 		bb.B = marshalUint64String(bb.B[:0], c.maxValue)

lib/logstorage/stats_min.go

@@ -116,9 +116,9 @@ func (smp *statsMinProcessor) updateStateForColumn(br *blockResult, c *blockResu
 			smp.updateStateString(v)
 		}
 	case valueTypeDict:
-		for _, v := range c.dictValues {
+		c.forEachDictValue(br, func(v string) {
 			smp.updateStateString(v)
-		}
+		})
 	case valueTypeUint8, valueTypeUint16, valueTypeUint32, valueTypeUint64:
 		bb := bbPool.Get()
 		bb.B = marshalUint64String(bb.B[:0], c.minValue)

lib/logstorage/stats_row_max.go

@@ -82,12 +82,11 @@ func (smp *statsRowMaxProcessor) updateStatsForAllRows(br *blockResult) int {
 	case valueTypeString:
 		needUpdateState = true
 	case valueTypeDict:
-		for _, v := range c.dictValues {
+		c.forEachDictValue(br, func(v string) {
-			if smp.needUpdateStateString(v) {
+			if !needUpdateState && smp.needUpdateStateString(v) {
 				needUpdateState = true
-				break
 			}
-		}
+		})
 	case valueTypeUint8, valueTypeUint16, valueTypeUint32, valueTypeUint64:
 		bb := bbPool.Get()
 		bb.B = marshalUint64String(bb.B[:0], c.maxValue)

lib/logstorage/stats_row_min.go

@@ -82,12 +82,11 @@ func (smp *statsRowMinProcessor) updateStatsForAllRows(br *blockResult) int {
 	case valueTypeString:
 		needUpdateState = true
 	case valueTypeDict:
-		for _, v := range c.dictValues {
+		c.forEachDictValue(br, func(v string) {
-			if smp.needUpdateStateString(v) {
+			if !needUpdateState && smp.needUpdateStateString(v) {
 				needUpdateState = true
-				break
 			}
-		}
+		})
 	case valueTypeUint8, valueTypeUint16, valueTypeUint32, valueTypeUint64:
 		bb := bbPool.Get()
 		bb.B = marshalUint64String(bb.B[:0], c.minValue)

lib/logstorage/stats_uniq_values.go

@@ -74,9 +74,9 @@ func (sup *statsUniqValuesProcessor) updateStatsForAllRowsColumn(c *blockResultC
 	stateSizeIncrease := 0
 	if c.valueType == valueTypeDict {
 		// collect unique non-zero c.dictValues
-		for _, v := range c.dictValues {
+		c.forEachDictValue(br, func(v string) {
 			stateSizeIncrease += sup.updateState(v)
-		}
+		})
 		return stateSizeIncrease
 	}
 
@@ -181,14 +181,12 @@ func (sup *statsUniqValuesProcessor) updateState(v string) int {
 		// Skip empty values
 		return 0
 	}
-
+	if _, ok := sup.m[v]; ok {
-	stateSizeIncrease := 0
+		return 0
-	if _, ok := sup.m[v]; !ok {
-		vCopy := strings.Clone(v)
-		sup.m[vCopy] = struct{}{}
-		stateSizeIncrease += len(vCopy) + int(unsafe.Sizeof(vCopy))
 	}
-	return stateSizeIncrease
+	vCopy := strings.Clone(v)
+	sup.m[vCopy] = struct{}{}
+	return len(vCopy) + int(unsafe.Sizeof(vCopy))
 }
 
 func (sup *statsUniqValuesProcessor) limitReached() bool {