mount: improve read performance on random reads

1 files changed, 31 insertions, 0 deletions

diff --git a/weed/filer/reader_pattern.go b/weed/filer/reader_pattern.go
new file mode 100644
index 000000000..2bf18d141
--- /dev/null
+++ b/weed/filer/reader_pattern.go
@@ -0,0 +1,31 @@
+package filer
+
+type ReaderPattern struct {
+	isStreaming    bool
+	lastReadOffset int64
+}
+
+// For streaming read: only cache the first chunk
+// For random read: only fetch the requested range, instead of the whole chunk
+
+func NewReaderPattern() *ReaderPattern {
+	return &ReaderPattern{
+		isStreaming:    true,
+		lastReadOffset: 0,
+	}
+}
+
+func (rp *ReaderPattern) MonitorReadAt(offset int64, size int) {
+	if rp.lastReadOffset > offset {
+		rp.isStreaming = false
+	}
+	rp.lastReadOffset = offset
+}
+
+func (rp *ReaderPattern) IsStreamingMode() bool {
+	return rp.isStreaming
+}
+
+func (rp *ReaderPattern) IsRandomMode() bool {
+	return !rp.isStreaming
+}