3 files changed, 39 insertions, 21 deletions
diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index cbe71aab431..8290ce6e36e 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -956,6 +956,9 @@ env.Library(
     LIBDEPS=[
         "db_raii",
     ],
+    LIBDEPS_PRIVATE=[
+       "concurrency/write_conflict_exception",
+    ],
 )
 
 env.Library(
diff --git a/src/mongo/db/catalog/database.h b/src/mongo/db/catalog/database.h
index bf8c12638d2..1de4fa3e09e 100644
--- a/src/mongo/db/catalog/database.h
+++ b/src/mongo/db/catalog/database.h
@@ -133,6 +133,14 @@ public:
 
     virtual Status dropView(OperationContext* const opCtx, NamespaceString viewName) const = 0;
 
+    /**
+     * A MODE_IX collection lock must be held for this call. Throws a WriteConflictException error
+     * if the collection already exists (say if another thread raced to create it).
+     *
+     * Surrounding writeConflictRetry loops must encompass checking that the collection exists as
+     * well as creating it. Otherwise the loop will endlessly throw WCEs: the caller must check that
+     * the collection exists to break free.
+     */
     virtual Collection* createCollection(OperationContext* const opCtx,
                                          const NamespaceString& nss,
                                          const CollectionOptions& options = CollectionOptions(),
diff --git a/src/mongo/db/introspect.cpp b/src/mongo/db/introspect.cpp
index 3efdcf57c3f..a67929ff9b4 100644
--- a/src/mongo/db/introspect.cpp
+++ b/src/mongo/db/introspect.cpp
@@ -39,6 +39,7 @@
 #include "mongo/db/auth/user_set.h"
 #include "mongo/db/catalog/collection.h"
 #include "mongo/db/client.h"
+#include "mongo/db/concurrency/write_conflict_exception.h"
 #include "mongo/db/curop.h"
 #include "mongo/db/db_raii.h"
 #include "mongo/db/jsobj.h"
@@ -184,32 +185,38 @@ Status createProfileCollection(OperationContext* opCtx, Database* db) {
     invariant(!opCtx->shouldParticipateInFlowControl());
 
     const auto dbProfilingNS = NamespaceString(db->name(), "system.profile");
-    Collection* const collection =
-        CollectionCatalog::get(opCtx).lookupCollectionByNamespace(opCtx, dbProfilingNS);
-    if (collection) {
-        if (!collection->isCapped()) {
-            return Status(ErrorCodes::NamespaceExists,
-                          str::stream() << dbProfilingNS << " exists but isn't capped");
-        }
 
-        return Status::OK();
-    }
+    // Checking the collection exists must also be done in the WCE retry loop. Only retrying
+    // collection creation would endlessly throw errors because the collection exists: must check
+    // and see the collection exists in order to break free.
+    return writeConflictRetry(opCtx, "createProfileCollection", dbProfilingNS.ns(), [&] {
+        Collection* const collection =
+            CollectionCatalog::get(opCtx).lookupCollectionByNamespace(opCtx, dbProfilingNS);
+        if (collection) {
+            if (!collection->isCapped()) {
+                return Status(ErrorCodes::NamespaceExists,
+                              str::stream() << dbProfilingNS << " exists but isn't capped");
+            }
 
-    // system.profile namespace doesn't exist; create it
-    LOGV2(20701,
-          "Creating profile collection: {dbProfilingNS}",
-          "dbProfilingNS"_attr = dbProfilingNS);
+            return Status::OK();
+        }
+
+        // system.profile namespace doesn't exist; create it
+        LOGV2(20701,
+              "Creating profile collection: {dbProfilingNS}",
+              "dbProfilingNS"_attr = dbProfilingNS);
 
-    CollectionOptions collectionOptions;
-    collectionOptions.capped = true;
-    collectionOptions.cappedSize = 1024 * 1024;
+        CollectionOptions collectionOptions;
+        collectionOptions.capped = true;
+        collectionOptions.cappedSize = 1024 * 1024;
 
-    WriteUnitOfWork wunit(opCtx);
-    repl::UnreplicatedWritesBlock uwb(opCtx);
-    invariant(db->createCollection(opCtx, dbProfilingNS, collectionOptions));
-    wunit.commit();
+        WriteUnitOfWork wunit(opCtx);
+        repl::UnreplicatedWritesBlock uwb(opCtx);
+        invariant(db->createCollection(opCtx, dbProfilingNS, collectionOptions));
+        wunit.commit();
 
-    return Status::OK();
+        return Status::OK();
+    });
 }
 
 }  // namespace mongo