2 files changed, 5 insertions, 19 deletions
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_begin_transaction_block.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_begin_transaction_block.cpp
index 0954cdb7ddc..42ab62e3b2a 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_begin_transaction_block.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_begin_transaction_block.cpp
@@ -88,16 +88,9 @@ WiredTigerBeginTxnBlock::~WiredTigerBeginTxnBlock() {
 
 Status WiredTigerBeginTxnBlock::setReadSnapshot(Timestamp readTimestamp) {
     invariant(_rollback);
-    // Avoid heap allocation in favour of a stack allocation for the configuration string.
-    static constexpr auto configFmtString = "read_timestamp={:x}";
-    static constexpr auto numBytesRequired = std::char_traits<char>::length(configFmtString) +
-        (sizeof(decltype(readTimestamp.asULL())) * 2) + 1;
-    std::array<char, numBytesRequired> configString;
-    auto end =
-        fmt::format_to(configString.begin(), FMT_STRING(configFmtString), readTimestamp.asULL());
-    *end = '\0';
-
-    return wtRCToStatus(_session->timestamp_transaction(_session, configString.data()), _session);
+    return wtRCToStatus(
+        _session->timestamp_transaction_uint(_session, WT_TS_TXN_TYPE_READ, readTimestamp.asULL()),
+        _session);
 }
 
 void WiredTigerBeginTxnBlock::done() {
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp
index ab435ba9e09..4fe60f56356 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp
@@ -829,15 +829,8 @@ Status WiredTigerRecoveryUnit::setTimestamp(Timestamp timestamp) {
         return Status::OK();
     }
 
-    // Avoid heap allocation in favour of a stack allocation.
-    static constexpr auto formatString = "commit_timestamp={:X}";
-    static constexpr auto bytesToAllocate = std::char_traits<char>::length(formatString) +
-        (sizeof(decltype(timestamp.asULL())) * 2) + 1;
-    std::array<char, bytesToAllocate> conf;
-    auto end = fmt::format_to(conf.begin(), FMT_COMPILE(formatString), timestamp.asULL());
-    // Manual null-termination
-    *end = '\0';
-    auto rc = session->timestamp_transaction(session, conf.data());
+    auto rc =
+        session->timestamp_transaction_uint(session, WT_TS_TXN_TYPE_COMMIT, timestamp.asULL());
     if (rc == 0) {
         _isTimestamped = true;
     }