peapod: Do not commit idle batch transaction

Previously, Peapod collects write batch within 10ms and then flushes
changes to physical drive. In the absence of operations during the
lifetime of the current batch transaction, the latter was committed in
any case and a new one was begun. This behavior could lead to idle
commit-begin ops.

Now each state-changing batch is marked. The flush cycle commits only
non-idle batches: if current batch is idle, Peapod keeps related
transaction for the time interval. When Peapod is closed, transaction
related to idle batch is rolled back.

Signed-off-by: Leonard Lyubich <[email protected]>

pkg/local_object_storage/peapod/peapod.go

@@ -16,6 +16,8 @@ type batch struct {
 
 	tx *bbolt.Tx
 
+	nonIdle bool
+
 	commitErr   error
 	chCommitted chan struct{}
 
@@ -97,6 +99,14 @@ func (x *Peapod) flushLoop() {
 func (x *Peapod) flushCurrentBatch(beginNew bool) {
 	x.currentBatchMtx.Lock()
 
+	if !x.currentBatch.nonIdle {
+		if !beginNew {
+			_ = x.currentBatch.tx.Rollback()
+		}
+		x.currentBatchMtx.Unlock()
+		return
+	}
+
 	err := x.currentBatch.tx.Commit()
 	if err != nil {
 		err = fmt.Errorf("commit BoltDB batch transaction: %w", err)

pkg/local_object_storage/peapod/put.go

@@ -49,6 +49,8 @@ func (x *Peapod) Put(ctx context.Context, addr oid.Address, data []byte) error {
 		return fmt.Errorf("put object into BoltDB bucket for container: %w", err)
 	}
 
+	currentBatch.nonIdle = true
+
 	x.currentBatchMtx.RUnlock()
 
 	select {