diff --git a/src/backend/access/rmgrdesc/xactdesc.c b/src/backend/access/rmgrdesc/xactdesc.c
index 9b40f447ff..6d5ebd475b 100644
--- a/src/backend/access/rmgrdesc/xactdesc.c
+++ b/src/backend/access/rmgrdesc/xactdesc.c
@@ -104,18 +104,18 @@ ParseCommitRecord(uint8 info, xl_xact_commit *xlrec, xl_xact_parsed_commit *pars
 
 		if (parsed->xinfo & XACT_XINFO_HAS_GID)
 		{
-			int gidlen;
 			strlcpy(parsed->twophase_gid, data, sizeof(parsed->twophase_gid));
-			gidlen = strlen(data) + 1;
-			data += MAXALIGN(gidlen);
+			data += strlen(data) + 1;
 		}
 	}
 
+	/* Note: no alignment is guaranteed after this point */
+
 	if (parsed->xinfo & XACT_XINFO_HAS_ORIGIN)
 	{
 		xl_xact_origin xl_origin;
 
-		/* we're only guaranteed 4 byte alignment, so copy onto stack */
+		/* no alignment is guaranteed, so copy onto stack */
 		memcpy(&xl_origin, data, sizeof(xl_origin));
 
 		parsed->origin_lsn = xl_origin.origin_lsn;
@@ -188,18 +188,18 @@ ParseAbortRecord(uint8 info, xl_xact_abort *xlrec, xl_xact_parsed_abort *parsed)
 
 		if (parsed->xinfo & XACT_XINFO_HAS_GID)
 		{
-			int gidlen;
 			strlcpy(parsed->twophase_gid, data, sizeof(parsed->twophase_gid));
-			gidlen = strlen(data) + 1;
-			data += MAXALIGN(gidlen);
+			data += strlen(data) + 1;
 		}
 	}
 
+	/* Note: no alignment is guaranteed after this point */
+
 	if (parsed->xinfo & XACT_XINFO_HAS_ORIGIN)
 	{
 		xl_xact_origin xl_origin;
 
-		/* we're only guaranteed 4 byte alignment, so copy onto stack */
+		/* no alignment is guaranteed, so copy onto stack */
 		memcpy(&xl_origin, data, sizeof(xl_origin));
 
 		parsed->origin_lsn = xl_origin.origin_lsn;
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index d6e4b7980f..5c05d545c4 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -1129,9 +1129,11 @@ EndPrepare(GlobalTransaction gxact)
 	gxact->prepare_end_lsn = XLogInsert(RM_XACT_ID, XLOG_XACT_PREPARE);
 
 	if (replorigin)
+	{
 		/* Move LSNs forward for this replication origin */
 		replorigin_session_advance(replorigin_session_origin_lsn,
 								   gxact->prepare_end_lsn);
+	}
 
 	XLogFlush(gxact->prepare_end_lsn);
 
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 948733c1e3..4747353bb9 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -5245,9 +5245,7 @@ XactLogCommitRecord(TimestampTz commit_time,
 	xl_xact_invals xl_invals;
 	xl_xact_twophase xl_twophase;
 	xl_xact_origin xl_origin;
-
 	uint8		info;
-	int			gidlen = 0;
 
 	Assert(CritSectionCount > 0);
 
@@ -5313,10 +5311,7 @@ XactLogCommitRecord(TimestampTz commit_time,
 		Assert(twophase_gid != NULL);
 
 		if (XLogLogicalInfoActive())
-		{
 			xl_xinfo.xinfo |= XACT_XINFO_HAS_GID;
-			gidlen = strlen(twophase_gid) + 1; /* include '\0' */
-		}
 	}
 
 	/* dump transaction origin information */
@@ -5370,12 +5365,7 @@ XactLogCommitRecord(TimestampTz commit_time,
 	{
 		XLogRegisterData((char *) (&xl_twophase), sizeof(xl_xact_twophase));
 		if (xl_xinfo.xinfo & XACT_XINFO_HAS_GID)
-		{
-			static const char zeroes[MAXIMUM_ALIGNOF] = { 0 };
-			XLogRegisterData((char*) twophase_gid, gidlen);
-			if (MAXALIGN(gidlen) != gidlen)
-				XLogRegisterData((char*) zeroes, MAXALIGN(gidlen) - gidlen);
-		}
+			XLogRegisterData((char *) twophase_gid, strlen(twophase_gid));
 	}
 
 	if (xl_xinfo.xinfo & XACT_XINFO_HAS_ORIGIN)
@@ -5409,7 +5399,6 @@ XactLogAbortRecord(TimestampTz abort_time,
 	xl_xact_origin xl_origin;
 
 	uint8		info;
-	int			gidlen = 0;
 
 	Assert(CritSectionCount > 0);
 
@@ -5448,10 +5437,7 @@ XactLogAbortRecord(TimestampTz abort_time,
 		Assert(twophase_gid != NULL);
 
 		if (XLogLogicalInfoActive())
-		{
 			xl_xinfo.xinfo |= XACT_XINFO_HAS_GID;
-			gidlen = strlen(twophase_gid) + 1; /* include '\0' */
-		}
 	}
 
 	if (TransactionIdIsValid(twophase_xid) && XLogLogicalInfoActive())
@@ -5487,7 +5473,6 @@ XactLogAbortRecord(TimestampTz abort_time,
 	if (xl_xinfo.xinfo & XACT_XINFO_HAS_DBINFO)
 		XLogRegisterData((char *) (&xl_dbinfo), sizeof(xl_dbinfo));
 
-
 	if (xl_xinfo.xinfo & XACT_XINFO_HAS_SUBXACTS)
 	{
 		XLogRegisterData((char *) (&xl_subxacts),
@@ -5508,12 +5493,7 @@ XactLogAbortRecord(TimestampTz abort_time,
 	{
 		XLogRegisterData((char *) (&xl_twophase), sizeof(xl_xact_twophase));
 		if (xl_xinfo.xinfo & XACT_XINFO_HAS_GID)
-		{
-			static const char zeroes[MAXIMUM_ALIGNOF] = { 0 };
-			XLogRegisterData((char*) twophase_gid, gidlen);
-			if (MAXALIGN(gidlen) != gidlen)
-				XLogRegisterData((char*) zeroes, MAXALIGN(gidlen) - gidlen);
-		}
+			XLogRegisterData((char *) twophase_gid, strlen(twophase_gid) + 1);
 	}
 
 	if (xl_xinfo.xinfo & XACT_XINFO_HAS_ORIGIN)
diff --git a/src/include/access/xact.h b/src/include/access/xact.h
index a46396f2d9..3661b8d090 100644
--- a/src/include/access/xact.h
+++ b/src/include/access/xact.h
@@ -269,6 +269,7 @@ typedef struct xl_xact_commit
 	/* xl_xact_relfilenodes follows if XINFO_HAS_RELFILENODES */
 	/* xl_xact_invals follows if XINFO_HAS_INVALS */
 	/* xl_xact_twophase follows if XINFO_HAS_TWOPHASE */
+	/* twophase_gid follows if XINFO_HAS_GID. As a null-terminated string. */
 	/* xl_xact_origin follows if XINFO_HAS_ORIGIN, stored unaligned! */
 } xl_xact_commit;
 #define MinSizeOfXactCommit (offsetof(xl_xact_commit, xact_time) + sizeof(TimestampTz))
@@ -278,11 +279,13 @@ typedef struct xl_xact_abort
 	TimestampTz xact_time;		/* time of abort */
 
 	/* xl_xact_xinfo follows if XLOG_XACT_HAS_INFO */
-	/* No db_info required */
+	/* xl_xact_dbinfo follows if XINFO_HAS_DBINFO */
 	/* xl_xact_subxacts follows if HAS_SUBXACT */
 	/* xl_xact_relfilenodes follows if HAS_RELFILENODES */
 	/* No invalidation messages needed. */
 	/* xl_xact_twophase follows if XINFO_HAS_TWOPHASE */
+	/* twophase_gid follows if XINFO_HAS_GID. As a null-terminated string. */
+	/* xl_xact_origin follows if XINFO_HAS_ORIGIN, stored unaligned! */
 } xl_xact_abort;
 #define MinSizeOfXactAbort sizeof(xl_xact_abort)
 
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index a5c074642f..7c766836db 100644
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -31,7 +31,7 @@
 /*
  * Each page of XLOG file has a header like this:
  */
-#define XLOG_PAGE_MAGIC 0xD097	/* can be used as WAL version indicator */
+#define XLOG_PAGE_MAGIC 0xD098	/* can be used as WAL version indicator */
 
 typedef struct XLogPageHeaderData
 {