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Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

tsdb/chunks/chunk_write_queue.go

@@ -24,7 +24,11 @@ import (
 )
 
 const (
-	chunkRefMapFreeThreshold   = 10
+	// Minimum recorded peak since since the last freeing
+	// of chunkWriteQueue.chunkrefMap to free it again.
+	chunkRefMapFreeThreshold = 10
+
+	// Minimum interval between freeing of chunkWriteQueue.chunkRefMap.
 	chunkRefMapMinFreeInterval = 10 * time.Minute
 )
 
@@ -122,13 +126,14 @@ func (c *chunkWriteQueue) processJob(job chunkWriteJob) {
 
 	c.completed.Inc()
 
-	if len(c.chunkRefMap) == 0 && c.chunkRefMapPeak > chunkRefMapFreeThreshold && time.Since(c.chunkRefMapLastFree) > chunkRefMapMinFreeInterval {
+	now := time.Now()
+	if len(c.chunkRefMap) == 0 && c.chunkRefMapPeak > chunkRefMapFreeThreshold && now.Sub(c.chunkRefMapLastFree) > chunkRefMapMinFreeInterval {
 		// Re-initialize the chunk ref map to half of the peak size that was in use since the last re-init event.
 		// By setting it to half of the peak we try to minimize the number of allocations required for a "normal" usage
 		// while ensuring that if its usage has decreased we shrink it over time.
 		c.chunkRefMap = make(map[ChunkDiskMapperRef]chunkenc.Chunk, c.chunkRefMapPeak/2)
 		c.chunkRefMapPeak = 0
-		c.chunkRefMapLastFree = time.Now()
+		c.chunkRefMapLastFree = now
 	}
 }