diff --git a/btr/btr0cur.c b/btr/btr0cur.c
index d610c0bf7b6..b3932f07a1a 100644
--- a/btr/btr0cur.c
+++ b/btr/btr0cur.c
@@ -3165,9 +3165,7 @@ btr_estimate_number_of_different_key_vals(
 
 	n_cols = dict_index_get_n_unique(index);
 
-	n_diff = mem_alloc((n_cols + 1) * sizeof(ib_longlong));
-
-	memset(n_diff, 0, (n_cols + 1) * sizeof(ib_longlong));
+	n_diff = mem_calloc((n_cols + 1) * sizeof(ib_longlong));
 
 	/* We sample some pages in the index to get an estimate */
 
diff --git a/include/row0ext.ic b/include/row0ext.ic
index 75244aa8c13..bdd5557a2b6 100644
--- a/include/row0ext.ic
+++ b/include/row0ext.ic
@@ -43,6 +43,7 @@ row_ext_create(
 	ret->buf = mem_heap_alloc(heap, n_ext * REC_MAX_INDEX_COL_LEN);
 #ifdef UNIV_DEBUG
 	memset(ret->buf, 0xaa, n_ext * REC_MAX_INDEX_COL_LEN);
+	UNIV_MEM_ALLOC(ret->buf, n_ext * REC_MAX_INDEX_COL_LEN);
 #endif
 	memset(ret->len, 0, n_ext * sizeof *ret->len);
 
diff --git a/row/row0mysql.c b/row/row0mysql.c
index 82aac4d9845..4c33bb38dc7 100644
--- a/row/row0mysql.c
+++ b/row/row0mysql.c
@@ -599,9 +599,7 @@ row_create_prebuilt(
 
 	heap = mem_heap_create(sizeof *prebuilt + 128);
 
-	prebuilt = mem_heap_alloc(heap, sizeof *prebuilt);
-
-	memset(prebuilt, 0, sizeof *prebuilt);
+	prebuilt = mem_heap_calloc(heap, sizeof *prebuilt);
 
 	prebuilt->magic_n = ROW_PREBUILT_ALLOCATED;
 	prebuilt->magic_n2 = ROW_PREBUILT_ALLOCATED;