Implement VACUUM FULL support for OrioleDB tables.

src/backend/access/heap/heapam_handler.c

@@ -3019,6 +3019,7 @@ static const TableAmRoutine heapam_methods = {
 	.relation_nontransactional_truncate = heapam_relation_nontransactional_truncate,
 	.relation_copy_data = heapam_relation_copy_data,
 	.relation_copy_for_cluster = heapam_relation_copy_for_cluster,
+	.relation_cluster = NULL,
 	.relation_vacuum = heap_vacuum_rel,
 	.scan_analyze_next_block = heapam_scan_analyze_next_block,
 	.scan_analyze_next_tuple = heapam_scan_analyze_next_tuple,

src/backend/commands/cluster.c

@@ -474,7 +474,10 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	TransferPredicateLocksToHeapRelation(OldHeap);
 
 	/* rebuild_relation does all the dirty work */
-	rebuild_relation(OldHeap, indexOid, verbose);
+	if (OldHeap->rd_tableam && OldHeap->rd_tableam->relation_cluster)
+		OldHeap->rd_tableam->relation_cluster(OldHeap, verbose);
+	else
+		rebuild_relation(OldHeap, indexOid, verbose);
 
 	/* NB: rebuild_relation does table_close() on OldHeap */
 

src/include/access/tableam.h

@@ -920,6 +920,11 @@ typedef struct TableAmRoutine
 								  BlockNumber *totalpages);
 
 	bytea	   *(*reloptions) (char relkind, Datum reloptions, bool validate);
+
+	/* hook for relation clustering. */
+	void		(*relation_cluster) (Relation OldTable,
+									 bool verbose);
+
 } TableAmRoutine;