[IndexedDB] Adding txn, value, and key size metrics

content/browser/indexed_db/indexed_db_transaction.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/indexed_db/indexed_db_transaction.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/browser/indexed_db/indexed_db_backing_store.h"
 #include "content/browser/indexed_db/indexed_db_cursor.h"
 #include "content/browser/indexed_db/indexed_db_database.h"
 #include "content/browser/indexed_db/indexed_db_database_callbacks.h"
 #include "content/browser/indexed_db/indexed_db_tracing.h"
 #include "content/browser/indexed_db/indexed_db_transaction_coordinator.h"
@@ skipping 308 matching lines @@
 
 leveldb::Status IndexedDBTransaction::CommitPhaseTwo() {
   // Abort may have been called just as the blob write completed.
   if (state_ == FINISHED)
     return leveldb::Status::OK();
 
   DCHECK_EQ(state_, COMMITTING);
 
   state_ = FINISHED;
 
+  UMA_HISTOGRAM_MEMORY_KB("WebCore.IndexedDB.Transaction.SizeOnCommit",
+                          transaction_->transaction()->GetTransactionSize());
+
   leveldb::Status s;
   bool committed;
   if (!used_) {
     committed = true;
   } else {
     s = transaction_->CommitPhaseTwo();
     committed = s.ok();
   }
 
   // Backing store resources (held via cursors) must be released
   // before script callbacks are fired, as the script callbacks may
   // release references and allow the backing store itself to be
   // released, and order is critical.
   CloseOpenCursors();
+  UMA_HISTOGRAM_MEMORY_KB("WebCore.IndexedDB.TransactionSize",

[pwnall, 2017/05/23 23:01:09]

Is this number different because of the blob journal changes in CommitPhaseTwo?
Can you please add a comment explaining?

[dmurph, 2017/05/24 02:01:58]

Had this wrong - put in right spot now, with comment.

+                          transaction_->transaction()->GetTransactionSize());
   transaction_->Reset();
 
   // Transactions must also be marked as completed before the
   // front-end is notified, as the transaction completion unblocks
   // operations like closing connections.
   database_->transaction_coordinator().DidFinishTransaction(this);
 
   if (committed) {
     abort_task_stack_.clear();
 
@@ skipping 157 matching lines @@
 
 ::indexed_db::mojom::ObserverChangesPtr*
 IndexedDBTransaction::GetPendingChangesForConnection(int32_t connection_id) {
   auto it = connection_changes_map_.find(connection_id);
   if (it != connection_changes_map_.end())
     return &it->second;
   return nullptr;
 }
 
 }  // namespace content