SERVER-43259 add IndexBuildsCoordinator::supportsTwoPhaseIndexBuild()

2 files changed, 24 insertions, 0 deletions

diff --git a/src/mongo/db/index_builds_coordinator.cpp b/src/mongo/db/index_builds_coordinator.cpp
index 3a0999821cc..f0afc33c0d8 100644
--- a/src/mongo/db/index_builds_coordinator.cpp
+++ b/src/mongo/db/index_builds_coordinator.cpp
@@ -42,6 +42,7 @@
 #include "mongo/db/concurrency/write_conflict_exception.h"
 #include "mongo/db/curop.h"
 #include "mongo/db/db_raii.h"
+#include "mongo/db/enable_two_phase_index_build_gen.h"
 #include "mongo/db/index_build_entry_helpers.h"
 #include "mongo/db/op_observer.h"
 #include "mongo/db/operation_context.h"
@@ -152,6 +153,23 @@ IndexBuildsCoordinator::~IndexBuildsCoordinator() {
     invariant(_collectionIndexBuilds.empty());
 }
 
+bool IndexBuildsCoordinator::supportsTwoPhaseIndexBuild() const {
+    if (!enableTwoPhaseIndexBuild) {
+        return false;
+    }
+
+    if (!serverGlobalParams.featureCompatibility.isVersionInitialized()) {
+        return false;
+    }
+
+    if (serverGlobalParams.featureCompatibility.getVersion() !=
+        ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo44) {
+        return false;
+    }
+
+    return true;
+}
+
 StatusWith<std::pair<long long, long long>> IndexBuildsCoordinator::startIndexRebuildForRecovery(
     OperationContext* opCtx,
     const NamespaceString& nss,
diff --git a/src/mongo/db/index_builds_coordinator.h b/src/mongo/db/index_builds_coordinator.h
index ff2f75fd288..7ab40ef1e85 100644
--- a/src/mongo/db/index_builds_coordinator.h
+++ b/src/mongo/db/index_builds_coordinator.h
@@ -101,6 +101,12 @@ public:
     static IndexBuildsCoordinator* get(OperationContext* operationContext);
 
     /**
+     * Returns true if two phase index builds are supported.
+     * This is determined by the current FCV and the server parameter 'enableTwoPhaseIndexBuild'.
+     */
+    bool supportsTwoPhaseIndexBuild() const;
+
+    /**
      * Sets up the in-memory and persisted state of the index build. A Future is returned upon which
      * the user can await the build result.
      *