diff --git a/server/core_storage.go b/server/core_storage.go
index 3240318cd..35e40ccf3 100644
--- a/server/core_storage.go
+++ b/server/core_storage.go
@@ -698,11 +698,16 @@ func storagePrepBatch(batch *pgx.Batch, authoritativeWrite bool, op *StorageOpWr
 		// Existing permission checks are not applicable for new storage objects.
 		query = `
 		INSERT INTO storage (collection, key, user_id, value, version, read, write, create_time, update_time)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, now(), now())
+		SELECT $1, $2, $3, $4, $5, $6, $7, now(), now()
+			WHERE NOT EXISTS(SELECT 1 FROM storage WHERE collection = $1 AND key = $2 AND user_id = $3) -- avoids ON CONFLICT hitting pre-existing object, and immediately cancels insert
+		ON CONFLICT (collection, key, user_id) DO UPDATE
+			SET version = excluded.version
+			WHERE storage.version = excluded.version AND storage.read = excluded.read AND storage.write = excluded.write -- needed to return a row on concurrent write of same object
 		RETURNING read, write, version, create_time, update_time`
 
 		// Outcomes:
-		// - NoRows - insert failed due to constraint violation (concurrent insert)
+		// - Row is returned if object was new or if concurrent writer wrote object with the same values (ON CONFLICT UPDATE needed)
+		// - NoRows - insert was ignored due to constraint violation (non-OCC already existing row), or concurrent write wrote object with different values (UPDATE did not happen)
 	}
 
 	batch.Queue(query, params...)