quick attempt to fix broken decoding of compound primary key updates

Author: kelvich

src/backend/access/rmgrdesc/heapdesc.c

@@ -36,6 +36,7 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 {
 	char	   *rec = XLogRecGetData(record);
 	uint8		info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
+	bool		isinit = (XLogRecGetInfo(record) & XLOG_HEAP_INIT_PAGE) != 0;
 
 	info &= XLOG_HEAP_OPMASK;
 	if (info == XLOG_HEAP_INSERT)
@@ -53,7 +54,12 @@ heap_desc(StringInfo buf, XLogReaderState *record)
 	}
 	else if (info == XLOG_HEAP_UPDATE)
 	{
-		xl_heap_update *xlrec = (xl_heap_update *) rec;
+		xl_heap_update *xlrec;
+
+		if (isinit)
+			rec += sizeof(TransactionId);
+
+		xlrec = (xl_heap_update *) rec;
 
 		appendStringInfo(buf, "off %u xmax " XID_FMT " ",
 						 xlrec->old_offnum,

src/backend/replication/logical/decode.c

@@ -876,6 +876,11 @@ DecodeUpdate(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
 		/* caution, remaining data in record is not aligned */
 		data = XLogRecGetData(r) + SizeOfHeapUpdate;
 		datalen = XLogRecGetDataLen(r) - SizeOfHeapUpdate;
+		if (isinit)
+		{
+			data += sizeof(TransactionId);
+			datalen -= sizeof(TransactionId);
+		}
 		tuplelen = datalen - SizeOfHeapHeader;
 
 		change->data.tp.oldtuple =