Limit memory usage, add several sync.Pool

backend/generic.go

@@ -5,8 +5,11 @@ import (
 	"compress/zlib"
 	"crypto/sha256"
 	"io/ioutil"
+	"sync"
 )
 
+var idPool = sync.Pool{New: func() interface{} { return ID(make([]byte, IDSize)) }}
+
 // Each lists all entries of type t in the backend and calls function f() with
 // the id and data.
 func Each(be Server, t Type, f func(id ID, data []byte, err error)) error {
@@ -78,7 +81,7 @@ func Uncompress(data []byte) []byte {
 // Hash returns the ID for data.
 func Hash(data []byte) ID {
 	h := sha256.Sum256(data)
-	id := make(ID, 32)
+	id := idPool.Get().(ID)
 	copy(id, h[:])
 	return id
 }