diff --git a/src/ivfkmeans.c b/src/ivfkmeans.c
index 78b4f51..e8c2c95 100644
--- a/src/ivfkmeans.c
+++ b/src/ivfkmeans.c
@@ -208,8 +208,8 @@ ElkanKmeans(Relation index, VectorArray samples, VectorArray centers)
 	if (totalSize / 1024 > maintenance_work_mem)
 		ereport(ERROR,
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
-				 errmsg("memory required is %zu MB, maintenance_work_mem is %zu MB",
-						totalSize / (1024 * 1024) + 1, ((Size) maintenance_work_mem) / 1024)));
+				 errmsg("memory required is %zu MB, maintenance_work_mem is %d MB",
+						totalSize / (1024 * 1024) + 1, maintenance_work_mem / 1024)));
 
 	/* Set support functions */
 	procinfo = index_getprocinfo(index, 1, IVFFLAT_KMEANS_DISTANCE_PROC);