Merge pull request #848 from prashanthpai/txn-store-metrics

txn context: Add store access counters

glusterd2/commands/volumes/volume-create-txn.go

@@ -163,8 +163,6 @@ func newVolinfo(req *api.VolCreateReq) (*volume.Volinfo, error) {
 
 func createVolinfo(c transaction.TxnCtx) error {
 
-	// TODO: Reduce the number of txn.Set calls.
-
 	var req api.VolCreateReq
 	if err := c.Get("req", &req); err != nil {
 		return err
@@ -187,10 +185,6 @@ func createVolinfo(c transaction.TxnCtx) error {
 		return err
 	}
 
-	// TODO: Volinfo already has this info. Right now, the key "bricks"
-	// is set separately to reuse the same step function (validateBricks)
-	// later in volume expand. Consider duplicating that code if store
-	// access turns out to be expensive.
 	if err := c.Set("bricks", volinfo.GetBricks()); err != nil {
 		return err
 	}

glusterd2/transaction/context.go

@@ -109,6 +109,8 @@ func (c *Tctx) commit() error {
 		return err
 	}
 
+	expTxn.Add("txn_ctx_store_commit", 1)
+
 	c.readCacheDirty = true
 
 	return nil
@@ -133,6 +135,7 @@ func (c *Tctx) Get(key string, value interface{}) error {
 			c.logger.WithError(err).WithField("key", key).Error("failed to get key from transaction context")
 			return err
 		}
+		expTxn.Add("txn_ctx_store_get", 1)
 		for _, kv := range resp.Kvs {
 			c.readSet[string(kv.Key)] = kv.Value
 		}
@@ -174,6 +177,7 @@ func (c *Tctx) Delete(key string) error {
 			"failed to delete key")
 		return err
 	}
+	expTxn.Add("txn_ctx_store_delete", 1)
 	return nil
 }
 

glusterd2/transaction/transaction.go

@@ -134,6 +134,7 @@ func (t *Txn) Do() error {
 		}
 
 		if err := s.do(t.Ctx); err != nil {
+			expTxn.Add("initiated_txn_failure", 1)
 			if !t.DisableRollback {
 				t.Ctx.Logger().WithError(err).Error("Transaction failed, rolling back changes")
 				t.undo(i)
@@ -142,6 +143,7 @@ func (t *Txn) Do() error {
 		}
 	}
 
+	expTxn.Add("initiated_txn_success", 1)
 	return nil
 }