From 760d0220f4f21eabdf59ae0c0d0de65b9776f98b Mon Sep 17 00:00:00 2001
From: Michael Eischer <michael.eischer@fau.de>
Date: Sun, 30 Nov 2025 11:01:01 +0100
Subject: [PATCH] restorer: scale file cache with workers count

---
 internal/restorer/filerestorer.go | 10 ++++------
 internal/restorer/fileswriter.go  |  8 +++++---
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/internal/restorer/filerestorer.go b/internal/restorer/filerestorer.go
index bb7e6de23..d197bcf5b 100644
--- a/internal/restorer/filerestorer.go
+++ b/internal/restorer/filerestorer.go
@@ -79,12 +79,10 @@ func newFileRestorer(dst string,
 	workerCount := int(connections)
 
 	return &fileRestorer{
-		idx:         idx,
-		blobsLoader: blobsLoader,
-		startWarmup: startWarmup,
-		// use a large number of buckets to minimize bucket contention in filesWriter
-		// buckets are relatively cheap, so we can afford to have a lot of them
-		filesWriter:          newFilesWriter(1024, allowRecursiveDelete),
+		idx:                  idx,
+		blobsLoader:          blobsLoader,
+		startWarmup:          startWarmup,
+		filesWriter:          newFilesWriter(workerCount, allowRecursiveDelete),
 		zeroChunk:            repository.ZeroChunk(),
 		sparse:               sparse,
 		progress:             progress,
diff --git a/internal/restorer/fileswriter.go b/internal/restorer/fileswriter.go
index e69b74544..2b60f7185 100644
--- a/internal/restorer/fileswriter.go
+++ b/internal/restorer/fileswriter.go
@@ -37,12 +37,14 @@ type partialFile struct {
 }
 
 func newFilesWriter(count int, allowRecursiveDelete bool) *filesWriter {
-	buckets := make([]filesWriterBucket, count)
-	for b := 0; b < count; b++ {
+	// use a large number of buckets to minimize bucket contention
+	// creating a new file can be slow, so make sure that files typically end up in different buckets.
+	buckets := make([]filesWriterBucket, 1024)
+	for b := 0; b < len(buckets); b++ {
 		buckets[b].files = make(map[string]*partialFile)
 	}
 
-	cache, err := simplelru.NewLRU[string, *partialFile](50, func(_ string, wr *partialFile) {
+	cache, err := simplelru.NewLRU[string, *partialFile](count+50, func(_ string, wr *partialFile) {
 		// close the file only when it is not in use
 		if wr.users == 0 {
 			_ = wr.Close()