SERVER-36201 Refactor transactions metrics tracking code into TransactionMetricsObserver

1 files changed, 112 insertions, 0 deletions

diff --git a/src/mongo/db/transaction_metrics_observer.h b/src/mongo/db/transaction_metrics_observer.h
new file mode 100644
index 00000000000..a420f02d14a
--- /dev/null
+++ b/src/mongo/db/transaction_metrics_observer.h
@@ -0,0 +1,112 @@
+/**
+ *    Copyright (C) 2018 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/db/curop.h"
+#include "mongo/db/server_transactions_metrics.h"
+#include "mongo/db/single_transaction_stats.h"
+#include "mongo/db/stats/top.h"
+
+namespace mongo {
+
+/**
+ * Updates transaction metrics (per-transaction metrics and server-wide transactions metrics) upon
+ * the appropriate transaction event.
+ */
+class TransactionMetricsObserver {
+
+public:
+    /**
+     * Updates relevant metrics when a transaction begins.
+     */
+    void onStart(ServerTransactionsMetrics* serverTransactionMetrics, unsigned long long curTime);
+
+    /**
+     * Updates relevant metrics when a transaction stashes its resources.
+     */
+    void onStash(ServerTransactionsMetrics* serverTransactionMetrics, unsigned long long curTime);
+
+    /**
+     * Updates relevant metrics when a transaction unstashes its resources.
+     */
+    void onUnstash(ServerTransactionsMetrics* serverTransactionsMetrics,
+                   unsigned long long curTime);
+
+    /**
+     * Updates relevant metrics when a transaction commits.
+     */
+    void onCommit(ServerTransactionsMetrics* serverTransactionsMetrics,
+                  unsigned long long curTime,
+                  Top* top);
+
+    /**
+     * Updates relevant metrics when an active transaction aborts.
+     */
+    void onAbortActive(ServerTransactionsMetrics* serverTransactionsMetrics,
+                       unsigned long long curTime,
+                       Top* top);
+
+    /**
+     * Updates relevant metrics when an inactive transaction aborts.
+     */
+    void onAbortInactive(ServerTransactionsMetrics* serverTransactionsMetrics,
+                         unsigned long long curTime,
+                         Top* top);
+
+    /**
+     * Updates relevant metrics when an operation running on the transaction completes. An operation
+     * may be a read/write operation, or an abort/commit command.
+     */
+    void onTransactionOperation(Client* client, OpDebug::AdditiveMetrics additiveMetrics);
+
+    /**
+     * Returns the SingleTransactionStats object stored in this TransactionMetricsObserver instance.
+     */
+    SingleTransactionStats getSingleTransactionStats() const {
+        return _singleTransactionStats;
+    }
+
+    /**
+     * Resets the SingleTransactionStats object stored in this TransactionMetricsObserver instance.
+     */
+    void resetSingleTransactionStats() {
+        _singleTransactionStats = SingleTransactionStats();
+    }
+
+private:
+    // Updates relevant metrics for any generic transaction abort.
+    void _onAbort(ServerTransactionsMetrics* serverTransactionsMetrics,
+                  unsigned long long curTime,
+                  Top* top);
+
+    // Tracks metrics for a single multi-document transaction.
+    SingleTransactionStats _singleTransactionStats;
+};
+
+}  // namespace mongo