diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 537d0e8cef..52c3790195 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -622,12 +622,12 @@ refresh_by_match_merge(Oid matviewOid, Oid tempOid, Oid relowner,
 	 */
 	resetStringInfo(&querybuf);
 	appendStringInfo(&querybuf,
-					 "SELECT newdata FROM %s newdata "
-					 "WHERE newdata IS NOT NULL AND EXISTS "
-					 "(SELECT 1 FROM %s newdata2 WHERE newdata2 IS NOT NULL "
-					 "AND newdata2 OPERATOR(pg_catalog.*=) newdata "
-					 "AND newdata2.ctid OPERATOR(pg_catalog.<>) "
-					 "newdata.ctid)",
+					 "SELECT _$newdata FROM %s _$newdata "
+					 "WHERE _$newdata IS NOT NULL AND EXISTS "
+					 "(SELECT 1 FROM %s _$newdata2 WHERE _$newdata2 IS NOT NULL "
+					 "AND _$newdata2 OPERATOR(pg_catalog.*=) _$newdata "
+					 "AND _$newdata2.ctid OPERATOR(pg_catalog.<>) "
+					 "_$newdata.ctid)",
 					 tempname, tempname);
 	if (SPI_execute(querybuf.data, false, 1) != SPI_OK_SELECT)
 		elog(ERROR, "SPI_exec failed: %s", querybuf.data);
@@ -655,8 +655,8 @@ refresh_by_match_merge(Oid matviewOid, Oid tempOid, Oid relowner,
 	resetStringInfo(&querybuf);
 	appendStringInfo(&querybuf,
 					 "CREATE TEMP TABLE %s AS "
-					 "SELECT mv.ctid AS tid, newdata "
-					 "FROM %s mv FULL JOIN %s newdata ON (",
+					 "SELECT _$mv.ctid AS tid, _$newdata "
+					 "FROM %s _$mv FULL JOIN %s _$newdata ON (",
 					 diffname, matviewname, tempname);
 
 	/*
@@ -749,9 +749,9 @@ refresh_by_match_merge(Oid matviewOid, Oid tempOid, Oid relowner,
 				if (foundUniqueIndex)
 					appendStringInfoString(&querybuf, " AND ");
 
-				leftop = quote_qualified_identifier("newdata",
+				leftop = quote_qualified_identifier("_$newdata",
 													NameStr(attr->attname));
-				rightop = quote_qualified_identifier("mv",
+				rightop = quote_qualified_identifier("_$mv",
 													 NameStr(attr->attname));
 
 				generate_operator_clause(&querybuf,
@@ -779,8 +779,8 @@ refresh_by_match_merge(Oid matviewOid, Oid tempOid, Oid relowner,
 	Assert(foundUniqueIndex);
 
 	appendStringInfoString(&querybuf,
-						   " AND newdata OPERATOR(pg_catalog.*=) mv) "
-						   "WHERE newdata IS NULL OR mv IS NULL "
+						   " AND _$newdata OPERATOR(pg_catalog.*=) _$mv) "
+						   "WHERE _$newdata IS NULL OR _$mv IS NULL "
 						   "ORDER BY tid");
 
 	/* Create the temporary "diff" table. */
@@ -806,10 +806,10 @@ refresh_by_match_merge(Oid matviewOid, Oid tempOid, Oid relowner,
 	/* Deletes must come before inserts; do them first. */
 	resetStringInfo(&querybuf);
 	appendStringInfo(&querybuf,
-					 "DELETE FROM %s mv WHERE ctid OPERATOR(pg_catalog.=) ANY "
-					 "(SELECT diff.tid FROM %s diff "
-					 "WHERE diff.tid IS NOT NULL "
-					 "AND diff.newdata IS NULL)",
+					 "DELETE FROM %s _$mv WHERE ctid OPERATOR(pg_catalog.=) ANY "
+					 "(SELECT _$diff.tid FROM %s _$diff "
+					 "WHERE _$diff.tid IS NOT NULL "
+					 "AND _$diff._$newdata IS NULL)",
 					 matviewname, diffname);
 	if (SPI_exec(querybuf.data, 0) != SPI_OK_DELETE)
 		elog(ERROR, "SPI_exec failed: %s", querybuf.data);
@@ -817,8 +817,8 @@ refresh_by_match_merge(Oid matviewOid, Oid tempOid, Oid relowner,
 	/* Inserts go last. */
 	resetStringInfo(&querybuf);
 	appendStringInfo(&querybuf,
-					 "INSERT INTO %s SELECT (diff.newdata).* "
-					 "FROM %s diff WHERE tid IS NULL",
+					 "INSERT INTO %s SELECT (_$diff._$newdata).* "
+					 "FROM %s _$diff WHERE tid IS NULL",
 					 matviewname, diffname);
 	if (SPI_exec(querybuf.data, 0) != SPI_OK_INSERT)
 		elog(ERROR, "SPI_exec failed: %s", querybuf.data);