--- \dll\postgresql-12.0\a\backend\access\rmgrdesc\xactdesc.c	Mon Sep 30 17:06:55 2019
+++ xactdesc.c	Fri Nov 22 13:40:13 2019
@@ -35,7 +35,7 @@
 {
 	char	   *data = ((char *) xlrec) + MinSizeOfXactCommit;
 
-	memset(parsed, 0, sizeof(*parsed));
+	memset(parsed, 0, sizeof(xl_xact_parsed_commit));
 
 	parsed->xinfo = 0;			/* default, if no XLOG_XACT_HAS_INFO is
 								 * present */
@@ -130,7 +130,7 @@
 {
 	char	   *data = ((char *) xlrec) + MinSizeOfXactAbort;
 
-	memset(parsed, 0, sizeof(*parsed));
+	memset(parsed, 0, sizeof(xl_xact_parsed_commit));
 
 	parsed->xinfo = 0;			/* default, if no XLOG_XACT_HAS_INFO is
 								 * present */