diff --git a/lib/logstorage/pipes.go b/lib/logstorage/pipes.go
index 5106c1c1e..0f2e6b35c 100644
--- a/lib/logstorage/pipes.go
+++ b/lib/logstorage/pipes.go
@@ -346,15 +346,11 @@ func (spp *statsPipeProcessor) writeBlock(workerID uint, timestamps []int64, col
 	byFields := spp.sp.byFields
 	if len(byFields) == 0 {
 		// Fast path - pass all the rows to a single group with empty key.
-		sfps := shard.getStatsFuncProcessors(nil)
-		for _, sfp := range sfps {
+		for _, sfp := range shard.getStatsFuncProcessors(nil) {
 			shard.stateSizeBudget -= sfp.updateStatsForAllRows(timestamps, columns)
 		}
 		return
 	}
-
-	// Slow path - update per-row stats
-
 	if len(byFields) == 1 {
 		// Special case for grouping by a single column.
 		idx := getBlockColumnIndex(columns, byFields[0])
@@ -363,6 +359,16 @@ func (spp *statsPipeProcessor) writeBlock(workerID uint, timestamps []int64, col
 		}
 		values := columns[idx].Values
 
+		if isConstValue(values) {
+			// Fast path for column with constant value.
+			shard.keyBuf = encoding.MarshalBytes(shard.keyBuf[:0], bytesutil.ToUnsafeBytes(values[0]))
+			for _, sfp := range shard.getStatsFuncProcessors(shard.keyBuf) {
+				shard.stateSizeBudget -= sfp.updateStatsForAllRows(timestamps, columns)
+			}
+			return
+		}
+
+		// Slower path for column with different values.
 		var sfps []statsFuncProcessor
 		keyBuf := shard.keyBuf
 		for i := range timestamps {
@@ -378,11 +384,23 @@ func (spp *statsPipeProcessor) writeBlock(workerID uint, timestamps []int64, col
 		return
 	}
 
-	// The slowest path - group by multiple columns.
 	// Pre-calculate column values for byFields in order to speed up building group key in the loop below.
 	shard.columnValues = appendBlockColumnValues(shard.columnValues[:0], columns, spp.sp.byFields)
 	columnValues := shard.columnValues
 
+	if areConstValues(columnValues) {
+		// Fast path for columns with constant values.
+		keyBuf := shard.keyBuf[:0]
+		for _, values := range columnValues {
+			keyBuf = encoding.MarshalBytes(keyBuf, bytesutil.ToUnsafeBytes(values[0]))
+		}
+		for _, sfp := range shard.getStatsFuncProcessors(keyBuf) {
+			shard.stateSizeBudget -= sfp.updateStatsForAllRows(timestamps, columns)
+		}
+		return
+	}
+
+	// The slowest path - group by multiple columns.
 	var sfps []statsFuncProcessor
 	keyBuf := shard.keyBuf
 	for i := range timestamps {
@@ -390,7 +408,7 @@ func (spp *statsPipeProcessor) writeBlock(workerID uint, timestamps []int64, col
 		sameValue := sfps != nil
 		for _, values := range columnValues {
 			if values == nil {
-				continue
+				logger.Panicf("BUG: values cannot be nil here!")
 			}
 			if i <= 0 || values[i-1] != values[i] {
 				sameValue = false
@@ -401,11 +419,7 @@ func (spp *statsPipeProcessor) writeBlock(workerID uint, timestamps []int64, col
 			// Construct new key for the 'by (...)' fields
 			keyBuf = keyBuf[:0]
 			for _, values := range columnValues {
-				v := ""
-				if values != nil {
-					v = values[i]
-				}
-				keyBuf = encoding.MarshalBytes(keyBuf, bytesutil.ToUnsafeBytes(v))
+				keyBuf = encoding.MarshalBytes(keyBuf, bytesutil.ToUnsafeBytes(values[i]))
 			}
 			sfps = shard.getStatsFuncProcessors(keyBuf)
 		}
@@ -416,6 +430,28 @@ func (spp *statsPipeProcessor) writeBlock(workerID uint, timestamps []int64, col
 	shard.keyBuf = keyBuf
 }
 
+func areConstValues(valuess [][]string) bool {
+	for _, values := range valuess {
+		if !isConstValue(values) {
+			return false
+		}
+	}
+	return true
+}
+
+func isConstValue(values []string) bool {
+	if len(values) == 0 {
+		return false
+	}
+	vFirst := values[0]
+	for _, v := range values[1:] {
+		if v != vFirst {
+			return false
+		}
+	}
+	return true
+}
+
 func (spp *statsPipeProcessor) flush() error {
 	if n := spp.stateSizeBudget.Load(); n <= 0 {
 		return fmt.Errorf("cannot calculate [%s], since it requires more than %dMB of memory", spp.sp.String(), spp.maxStateSize/(1<<20))