fix: restart volumeserver sometime occurred out of memory error

weed/storage/volume_checking.go

@@ -61,6 +61,18 @@ func readIndexEntryAtOffset(indexFile *os.File, offset int64) (bytes []byte, err
 
 func verifyNeedleIntegrity(datFile backend.BackendStorageFile, v needle.Version, offset int64, key NeedleId, size Size) (lastAppendAtNs uint64, err error) {
 	n := new(needle.Needle)
+	// case: node total memory 8g, set volumeLimitSize=2048 , save 10 files, every file size 2.2g or more , when we restart the volume server , while see out of memory error
+	// fix: When the size of the last file exceeds 10M, consider directly returning the last modify time
+	if size > 10 * 1024 * 1024 {
+		bytes , err := needle.ReadNeedleBlob(datFile, offset+int64(size), 0, v);
+		if  err == nil {
+			if v == needle.Version3 {
+				tsOffset := NeedleHeaderSize + 0 + needle.NeedleChecksumSize
+				n.AppendAtNs = util.BytesToUint64(bytes[tsOffset : tsOffset+TimestampSize])
+			}
+		}
+		return n.AppendAtNs, err
+	}
 	if err = n.ReadData(datFile, offset, size, v); err != nil {
 		return n.AppendAtNs, fmt.Errorf("read data [%d,%d) : %v", offset, offset+int64(size), err)
 	}