Add subtransaction id synchronization in Relation.

src/backend/access/transam/subtrans.c

@@ -55,6 +55,8 @@
 #define TransactionIdToEntry(xid) ((xid) % (uint32) SUBTRANS_XACTS_PER_PAGE)
 
 
+subtransaction_id_hook_type subtransaction_id_hook = NULL;
+
 /*
  * Link to shared-memory data structures for SUBTRANS control
  */

src/backend/commands/cluster.c

@@ -26,6 +26,7 @@
 #include "access/tableam.h"
 #include "access/toast_internals.h"
 #include "access/transam.h"
+#include "access/subtrans.h"
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "catalog/catalog.h"
@@ -1255,6 +1256,12 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
 		rel2->rd_newRelfilenodeSubid = rel1->rd_newRelfilenodeSubid;
 		rel2->rd_firstRelfilenodeSubid = rel1->rd_firstRelfilenodeSubid;
 		RelationAssumeNewRelfilenode(rel1);
+
+		if (subtransaction_id_hook)
+		{
+			subtransaction_id_hook(rel2);
+		}
+
 		relation_close(rel1, NoLock);
 		relation_close(rel2, NoLock);
 	}

src/backend/commands/tablecmds.c

@@ -25,6 +25,7 @@
 #include "access/nbtree.h"
 #include "access/reloptions.h"
 #include "access/relscan.h"
+#include "access/subtrans.h"
 #include "access/sysattr.h"
 #include "access/tableam.h"
 #include "access/toast_compression.h"
@@ -10099,6 +10100,12 @@ ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
 
 		irel->rd_createSubid = stmt->oldCreateSubid;
 		irel->rd_firstRelfilenodeSubid = stmt->oldFirstRelfilenodeSubid;
+
+		if (subtransaction_id_hook)
+		{
+			subtransaction_id_hook(irel);
+		}
+
 		RelationPreserveStorage(irel->rd_node, true);
 		index_close(irel, NoLock);
 	}

src/backend/utils/cache/relcache.c

@@ -38,6 +38,7 @@
 #include "access/nbtree.h"
 #include "access/parallel.h"
 #include "access/reloptions.h"
+#include "access/subtrans.h"
 #include "access/sysattr.h"
 #include "access/table.h"
 #include "access/tableam.h"
@@ -1425,6 +1426,11 @@ RelationInitPhysicalAddr(Relation relation)
 			relation->rd_firstRelfilenodeSubid = TopSubTransactionId;
 		else
 			relation->rd_firstRelfilenodeSubid = InvalidSubTransactionId;
+
+		if (subtransaction_id_hook)
+		{
+			subtransaction_id_hook(relation);
+		}
 	}
 }
 
@@ -2924,6 +2930,11 @@ RelationForgetRelation(Oid rid)
 		 * transaction, we could opt to destroy the entry.)
 		 */
 		relation->rd_droppedSubid = GetCurrentSubTransactionId();
+
+		if (subtransaction_id_hook)
+		{
+			subtransaction_id_hook(relation);
+		}
 	}
 
 	RelationClearRelation(relation, false);
@@ -3642,6 +3653,11 @@ RelationBuildLocalRelation(const char *relname,
 	rel->rd_firstRelfilenodeSubid = InvalidSubTransactionId;
 	rel->rd_droppedSubid = InvalidSubTransactionId;
 
+	if (subtransaction_id_hook)
+	{
+		subtransaction_id_hook(rel);
+	}
+
 	/*
 	 * create a new tuple descriptor from the one passed in.  We do this
 	 * partly to copy it into the cache context, and partly because the new
@@ -4007,6 +4023,11 @@ RelationAssumeNewRelfilenode(Relation relation)
 	if (relation->rd_firstRelfilenodeSubid == InvalidSubTransactionId)
 		relation->rd_firstRelfilenodeSubid = relation->rd_newRelfilenodeSubid;
 
+	if (subtransaction_id_hook)
+	{
+		subtransaction_id_hook(relation);
+	}
+
 	/* Flag relation as needing eoxact cleanup (to clear these fields) */
 	EOXactListAdd(relation);
 }

src/include/access/subtrans.h

@@ -11,6 +11,8 @@
 #ifndef SUBTRANS_H
 #define SUBTRANS_H
 
+#include "utils/rel.h"
+
 /* Number of SLRU buffers to use for subtrans */
 #define NUM_SUBTRANS_BUFFERS	32
 
@@ -23,6 +25,10 @@ typedef struct SubTransData
 struct SlruCtlData;
 typedef struct SlruCtlData *SlruCtl;
 
+/* Hook for subtransaction id */
+typedef void (*subtransaction_id_hook_type) (Relation rel);
+extern PGDLLIMPORT subtransaction_id_hook_type subtransaction_id_hook;
+
 extern void SubTransSetParent(TransactionId xid, TransactionId parent);
 extern TransactionId SubTransGetParent(TransactionId xid);
 extern TransactionId SubTransGetTopmostTransaction(TransactionId xid);