lib/storage: return dedup interval in milliseconds from GetDedupInterval()

This removes duplicate .Milliseconds() calls after GetDedupInterval() calls.

app/vmselect/netstorage/netstorage.go

@@ -468,8 +468,7 @@ func (pts *packedTimeseries) Unpack(dst *Result, tbf *tmpBlocksFile, tr storage.
 	if firstErr != nil {
 		return firstErr
 	}
-	di := storage.GetDedupInterval()
-	dedupInterval := di.Milliseconds()
+	dedupInterval := storage.GetDedupInterval()
 	mergeSortBlocks(dst, sbs, dedupInterval)
 	return nil
 }

lib/storage/block_stream_writer.go

@@ -187,8 +187,7 @@ func (bsw *blockStreamWriter) MustClose() {
 func (bsw *blockStreamWriter) WriteExternalBlock(b *Block, ph *partHeader, rowsMerged *uint64, needDedup bool) {
 	atomic.AddUint64(rowsMerged, uint64(b.rowsCount()))
 	if needDedup {
-		di := GetDedupInterval()
-		dedupInterval := di.Milliseconds()
+		dedupInterval := GetDedupInterval()
 		b.deduplicateSamplesDuringMerge(dedupInterval)
 	}
 	headerData, timestampsData, valuesData := b.MarshalData(bsw.timestampsBlockOffset, bsw.valuesBlockOffset)

lib/storage/dedup.go

@@ -10,15 +10,15 @@ import (
 //
 // This function must be called before initializing the storage.
 func SetDedupInterval(dedupInterval time.Duration) {
-	globalDedupInterval = dedupInterval
+	globalDedupInterval = dedupInterval.Milliseconds()
 }
 
-// GetDedupInterval returns the dedup interval set via SetDedupInterval.
-func GetDedupInterval() time.Duration {
+// GetDedupInterval returns the dedup interval in milliseconds, which has been set via SetDedupInterval.
+func GetDedupInterval() int64 {
 	return globalDedupInterval
 }
 
-var globalDedupInterval time.Duration
+var globalDedupInterval int64
 
 // DeduplicateSamples removes samples from src* if they are closer to each other than dedupInterval in millseconds.
 func DeduplicateSamples(srcTimestamps []int64, srcValues []float64, dedupInterval int64) ([]int64, []float64) {