SERVER-25025 Make startup faster with many WT collections

This makes two major improvements:

(1) WiredTiger "metadata:create" cursors are very expensive; only use
these when absolutely necessary, and use standard "metadata:" cursors
everywhere else. This lowers startup calls to "metadata:create" from 3
to 1 per table.

(2) No longer open a cursor for every WiredTiger collection at startup.
Instead, lazily open cursors to initialize RecordIDs for inserts.

1 files changed, 2 insertions, 4 deletions

diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_size_storer.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_size_storer.cpp
index 76ddde766e0..e0847eb0444 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_size_storer.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_size_storer.cpp
@@ -116,10 +116,8 @@ std::shared_ptr<WiredTigerSizeStorer::SizeInfo> WiredTigerSizeStorer::load(Strin
     BSONObj data(reinterpret_cast<const char*>(value.data));
 
     LOG(2) << "WiredTigerSizeStorer::load " << uri << " -> " << redact(data);
-    auto result = std::make_shared<SizeInfo>();
-    result->numRecords.store(data["numRecords"].safeNumberLong());
-    result->dataSize.store(data["dataSize"].safeNumberLong());
-    return result;
+    return std::make_shared<SizeInfo>(data["numRecords"].safeNumberLong(),
+                                      data["dataSize"].safeNumberLong());
 }
 
 void WiredTigerSizeStorer::flush(bool syncToDisk) {