Refactor to make use of a common function for GetSubscriptionRelations and GetSubscriptionNotReadyRelations.

From 1f67e4b5ff2d304323f262e8acf74d48893ceb06 Mon Sep 17 00:00:00 2001
From: Vigneshwaran C <vignesh21@gmail.com>
Date: Wed, 13 Jul 2022 11:54:59 +0530
Subject: [PATCH v2] Refactor to make use of a common function for
 GetSubscriptionRelations and GetSubscriptionNotReadyRelations.

Most of the code is common between GetSubscriptionRelations and
GetSubscriptionNotReadyRelations. Added a parameter to GetSubscriptionRelations
which could provide the same functionality for GetSubscriptionRelations
and GetSubscriptionNotReadyRelations.
---
 src/backend/catalog/pg_subscription.c       | 71 ++++-----------------
 src/backend/commands/subscriptioncmds.c     |  5 +-
 src/backend/replication/logical/tablesync.c |  3 +-
 src/include/catalog/pg_subscription.h       |  3 +
 src/include/catalog/pg_subscription_rel.h   |  3 +-
 5 files changed, 20 insertions(+), 65 deletions(-)

diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c
index 8856ce3b50..cd7dc00c79 100644
--- a/src/backend/catalog/pg_subscription.c
+++ b/src/backend/catalog/pg_subscription.c
@@ -525,65 +525,15 @@ HasSubscriptionRelations(Oid subid)
 }
 
 /*
- * Get all relations for subscription.
+ * Get the relations for subscription.
  *
- * Returned list is palloc'ed in current memory context.
+ * If subrel_options is not set, return all the relations for subscription. If
+ * SUBSCRIPTION_REL_STATE_NOT_READY bit is set in subrel_options, return all
+ * the relations for subscription that are not in a ready state. Returned list
+ * is palloc'ed in current memory context.
  */
 List *
-GetSubscriptionRelations(Oid subid)
-{
-	List	   *res = NIL;
-	Relation	rel;
-	HeapTuple	tup;
-	ScanKeyData skey[1];
-	SysScanDesc scan;
-
-	rel = table_open(SubscriptionRelRelationId, AccessShareLock);
-
-	ScanKeyInit(&skey[0],
-				Anum_pg_subscription_rel_srsubid,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(subid));
-
-	scan = systable_beginscan(rel, InvalidOid, false,
-							  NULL, 1, skey);
-
-	while (HeapTupleIsValid(tup = systable_getnext(scan)))
-	{
-		Form_pg_subscription_rel subrel;
-		SubscriptionRelState *relstate;
-		Datum		d;
-		bool		isnull;
-
-		subrel = (Form_pg_subscription_rel) GETSTRUCT(tup);
-
-		relstate = (SubscriptionRelState *) palloc(sizeof(SubscriptionRelState));
-		relstate->relid = subrel->srrelid;
-		relstate->state = subrel->srsubstate;
-		d = SysCacheGetAttr(SUBSCRIPTIONRELMAP, tup,
-							Anum_pg_subscription_rel_srsublsn, &isnull);
-		if (isnull)
-			relstate->lsn = InvalidXLogRecPtr;
-		else
-			relstate->lsn = DatumGetLSN(d);
-
-		res = lappend(res, relstate);
-	}
-
-	/* Cleanup */
-	systable_endscan(scan);
-	table_close(rel, AccessShareLock);
-
-	return res;
-}
-
-/*
- * Get all relations for subscription that are not in a ready state.
- *
- * Returned list is palloc'ed in current memory context.
- */
-List *
-GetSubscriptionNotReadyRelations(Oid subid)
+GetSubscriptionRelations(Oid subid, bits32 subrel_state_options)
 {
 	List	   *res = NIL;
 	Relation	rel;
@@ -599,10 +549,11 @@ GetSubscriptionNotReadyRelations(Oid subid)
 				BTEqualStrategyNumber, F_OIDEQ,
 				ObjectIdGetDatum(subid));
 
-	ScanKeyInit(&skey[nkeys++],
-				Anum_pg_subscription_rel_srsubstate,
-				BTEqualStrategyNumber, F_CHARNE,
-				CharGetDatum(SUBREL_STATE_READY));
+	if ((subrel_state_options & SUBSCRIPTION_REL_STATE_NOT_READY) != 0)
+		ScanKeyInit(&skey[nkeys++],
+					Anum_pg_subscription_rel_srsubstate,
+					BTEqualStrategyNumber, F_CHARNE,
+					CharGetDatum(SUBREL_STATE_READY));
 
 	scan = systable_beginscan(rel, InvalidOid, false,
 							  NULL, nkeys, skey);
diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index bdc1208724..d9fb235ce5 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -785,7 +785,7 @@ AlterSubscription_refresh(Subscription *sub, bool copy_data,
 		pubrel_names = fetch_table_list(wrconn, sub->publications);
 
 		/* Get local table list. */
-		subrel_states = GetSubscriptionRelations(sub->oid);
+		subrel_states = GetSubscriptionRelations(sub->oid, 0);
 
 		/*
 		 * Build qsorted array of local table oids for faster lookup. This can
@@ -1457,7 +1457,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 * the apply and tablesync workers and they can't restart because of
 	 * exclusive lock on the subscription.
 	 */
-	rstates = GetSubscriptionNotReadyRelations(subid);
+	rstates = GetSubscriptionRelations(subid,
+									   SUBSCRIPTION_REL_STATE_NOT_READY);
 	foreach(lc, rstates)
 	{
 		SubscriptionRelState *rstate = (SubscriptionRelState *) lfirst(lc);
diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index 670c6fcada..d0bb6382c0 100644
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -1479,7 +1479,8 @@ FetchTableStates(bool *started_tx)
 		}
 
 		/* Fetch all non-ready tables. */
-		rstates = GetSubscriptionNotReadyRelations(MySubscription->oid);
+		rstates = GetSubscriptionRelations(MySubscription->oid,
+										   SUBSCRIPTION_REL_STATE_NOT_READY);
 
 		/* Allocate the tracking info in a permanent memory context. */
 		oldctx = MemoryContextSwitchTo(CacheMemoryContext);
diff --git a/src/include/catalog/pg_subscription.h b/src/include/catalog/pg_subscription.h
index d1260f590c..5ff428bcba 100644
--- a/src/include/catalog/pg_subscription.h
+++ b/src/include/catalog/pg_subscription.h
@@ -31,6 +31,9 @@
 #define LOGICALREP_TWOPHASE_STATE_PENDING 'p'
 #define LOGICALREP_TWOPHASE_STATE_ENABLED 'e'
 
+/* flag bits for getting the relevant subscription relations */
+#define SUBSCRIPTION_REL_STATE_NOT_READY 0x01	/* NOT READY relations */
+
 /* ----------------
  *		pg_subscription definition. cpp turns this into
  *		typedef struct FormData_pg_subscription
diff --git a/src/include/catalog/pg_subscription_rel.h b/src/include/catalog/pg_subscription_rel.h
index 9df99c3418..8f6c602860 100644
--- a/src/include/catalog/pg_subscription_rel.h
+++ b/src/include/catalog/pg_subscription_rel.h
@@ -88,7 +88,6 @@ extern char GetSubscriptionRelState(Oid subid, Oid relid, XLogRecPtr *sublsn);
 extern void RemoveSubscriptionRel(Oid subid, Oid relid);
 
 extern bool HasSubscriptionRelations(Oid subid);
-extern List *GetSubscriptionRelations(Oid subid);
-extern List *GetSubscriptionNotReadyRelations(Oid subid);
+extern List *GetSubscriptionRelations(Oid subid, bits32 subrel_state_options);
 
 #endif							/* PG_SUBSCRIPTION_REL_H */
-- 
2.32.0

From e0186ae685acb6334b711ea821b287be61d6cbd3 Mon Sep 17 00:00:00 2001
From: Vigneshwaran C <vignesh21@gmail.com>
Date: Wed, 13 Jul 2022 11:54:59 +0530
Subject: [PATCH v3] Refactor to make use of a common function for
 GetSubscriptionRelations and GetSubscriptionNotReadyRelations.

Most of the code is common between GetSubscriptionRelations and
GetSubscriptionNotReadyRelations. Added a parameter to GetSubscriptionRelations
which could provide the same functionality for GetSubscriptionRelations
and GetSubscriptionNotReadyRelations.
---
 src/backend/catalog/pg_subscription.c       | 71 ++++-----------------
 src/backend/commands/subscriptioncmds.c     |  5 +-
 src/backend/replication/logical/tablesync.c |  3 +-
 src/include/catalog/pg_subscription_rel.h   | 19 +++++-
 src/tools/pgindent/typedefs.list            |  1 +
 5 files changed, 34 insertions(+), 65 deletions(-)

diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c
index 8856ce3b50..46eedbc062 100644
--- a/src/backend/catalog/pg_subscription.c
+++ b/src/backend/catalog/pg_subscription.c
@@ -525,65 +525,15 @@ HasSubscriptionRelations(Oid subid)
 }
 
 /*
- * Get all relations for subscription.
+ * Get the relations for subscription.
  *
- * Returned list is palloc'ed in current memory context.
+ * If subrel_options is SUBSCRIPTION_REL_ALL, return all the relations for
+ * subscription. If SUBSCRIPTION_REL_NOT_READY, return all the relations for
+ * subscription that are not in a ready state. Returned list is palloc'ed in
+ * current memory context.
  */
 List *
-GetSubscriptionRelations(Oid subid)
-{
-	List	   *res = NIL;
-	Relation	rel;
-	HeapTuple	tup;
-	ScanKeyData skey[1];
-	SysScanDesc scan;
-
-	rel = table_open(SubscriptionRelRelationId, AccessShareLock);
-
-	ScanKeyInit(&skey[0],
-				Anum_pg_subscription_rel_srsubid,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(subid));
-
-	scan = systable_beginscan(rel, InvalidOid, false,
-							  NULL, 1, skey);
-
-	while (HeapTupleIsValid(tup = systable_getnext(scan)))
-	{
-		Form_pg_subscription_rel subrel;
-		SubscriptionRelState *relstate;
-		Datum		d;
-		bool		isnull;
-
-		subrel = (Form_pg_subscription_rel) GETSTRUCT(tup);
-
-		relstate = (SubscriptionRelState *) palloc(sizeof(SubscriptionRelState));
-		relstate->relid = subrel->srrelid;
-		relstate->state = subrel->srsubstate;
-		d = SysCacheGetAttr(SUBSCRIPTIONRELMAP, tup,
-							Anum_pg_subscription_rel_srsublsn, &isnull);
-		if (isnull)
-			relstate->lsn = InvalidXLogRecPtr;
-		else
-			relstate->lsn = DatumGetLSN(d);
-
-		res = lappend(res, relstate);
-	}
-
-	/* Cleanup */
-	systable_endscan(scan);
-	table_close(rel, AccessShareLock);
-
-	return res;
-}
-
-/*
- * Get all relations for subscription that are not in a ready state.
- *
- * Returned list is palloc'ed in current memory context.
- */
-List *
-GetSubscriptionNotReadyRelations(Oid subid)
+GetSubscriptionRelations(Oid subid, SubscriptionRelationState subrel_state)
 {
 	List	   *res = NIL;
 	Relation	rel;
@@ -599,10 +549,11 @@ GetSubscriptionNotReadyRelations(Oid subid)
 				BTEqualStrategyNumber, F_OIDEQ,
 				ObjectIdGetDatum(subid));
 
-	ScanKeyInit(&skey[nkeys++],
-				Anum_pg_subscription_rel_srsubstate,
-				BTEqualStrategyNumber, F_CHARNE,
-				CharGetDatum(SUBREL_STATE_READY));
+	if (subrel_state == SUBSCRIPTION_REL_NOT_READY)
+		ScanKeyInit(&skey[nkeys++],
+					Anum_pg_subscription_rel_srsubstate,
+					BTEqualStrategyNumber, F_CHARNE,
+					CharGetDatum(SUBREL_STATE_READY));
 
 	scan = systable_beginscan(rel, InvalidOid, false,
 							  NULL, nkeys, skey);
diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index bdc1208724..ac517dd539 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -785,7 +785,8 @@ AlterSubscription_refresh(Subscription *sub, bool copy_data,
 		pubrel_names = fetch_table_list(wrconn, sub->publications);
 
 		/* Get local table list. */
-		subrel_states = GetSubscriptionRelations(sub->oid);
+		subrel_states = GetSubscriptionRelations(sub->oid,
+												 SUBSCRIPTION_REL_ALL);
 
 		/*
 		 * Build qsorted array of local table oids for faster lookup. This can
@@ -1457,7 +1458,7 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 * the apply and tablesync workers and they can't restart because of
 	 * exclusive lock on the subscription.
 	 */
-	rstates = GetSubscriptionNotReadyRelations(subid);
+	rstates = GetSubscriptionRelations(subid, SUBSCRIPTION_REL_NOT_READY);
 	foreach(lc, rstates)
 	{
 		SubscriptionRelState *rstate = (SubscriptionRelState *) lfirst(lc);
diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index 670c6fcada..b072d9c349 100644
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -1479,7 +1479,8 @@ FetchTableStates(bool *started_tx)
 		}
 
 		/* Fetch all non-ready tables. */
-		rstates = GetSubscriptionNotReadyRelations(MySubscription->oid);
+		rstates = GetSubscriptionRelations(MySubscription->oid,
+										   SUBSCRIPTION_REL_NOT_READY);
 
 		/* Allocate the tracking info in a permanent memory context. */
 		oldctx = MemoryContextSwitchTo(CacheMemoryContext);
diff --git a/src/include/catalog/pg_subscription_rel.h b/src/include/catalog/pg_subscription_rel.h
index 9df99c3418..a4a45997b6 100644
--- a/src/include/catalog/pg_subscription_rel.h
+++ b/src/include/catalog/pg_subscription_rel.h
@@ -80,6 +80,21 @@ typedef struct SubscriptionRelState
 	char		state;
 } SubscriptionRelState;
 
+/*---------
+ * Expected values for subrel_state parameter of GetSubscriptionRelations(),
+ * which allows callers to specify which relations of the subscriptions they
+ * expect to see.
+ *
+ *	SUBSCRIPTION_REL_ALL:			all the subscription relations
+ *	SUBSCRIPTION_REL_NOT_READY:		all the subscription relations that are not
+ *  in ready state.
+ */
+typedef enum SubscriptionRelationState
+{
+	SUBSCRIPTION_REL_ALL,
+	SUBSCRIPTION_REL_NOT_READY
+} SubscriptionRelationState;
+
 extern void AddSubscriptionRelState(Oid subid, Oid relid, char state,
 									XLogRecPtr sublsn);
 extern void UpdateSubscriptionRelState(Oid subid, Oid relid, char state,
@@ -88,7 +103,7 @@ extern char GetSubscriptionRelState(Oid subid, Oid relid, XLogRecPtr *sublsn);
 extern void RemoveSubscriptionRel(Oid subid, Oid relid);
 
 extern bool HasSubscriptionRelations(Oid subid);
-extern List *GetSubscriptionRelations(Oid subid);
-extern List *GetSubscriptionNotReadyRelations(Oid subid);
+extern List *GetSubscriptionRelations(Oid subid,
+									  SubscriptionRelationState subrel_state);
 
 #endif							/* PG_SUBSCRIPTION_REL_H */
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 34a76ceb60..d2ff829735 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2641,6 +2641,7 @@ SubscriptingRefState
 Subscription
 SubscriptionInfo
 SubscriptionRelState
+SubscriptionRelationState
 SupportRequestCost
 SupportRequestIndexCondition
 SupportRequestRows
-- 
2.32.0

From e5edbf8dd47bbfcd7d8fcf3add8acab502e48665 Mon Sep 17 00:00:00 2001
From: Vigneshwaran C <vignesh21@gmail.com>
Date: Wed, 13 Jul 2022 11:54:59 +0530
Subject: [PATCH v4] Refactor to make use of a common function for
 GetSubscriptionRelations and GetSubscriptionNotReadyRelations.

Most of the code is common between GetSubscriptionRelations and
GetSubscriptionNotReadyRelations. Added a parameter to GetSubscriptionRelations
which could provide the same functionality for GetSubscriptionRelations
and GetSubscriptionNotReadyRelations.

Author: Vignesh C
Reviewed-By: Michael Paquier, Peter Smith, Amit Kapila, Kyotaro Horiguchi
Discussion: https://www.postgresql.org/message-id/flat/CALDaNm0eW-9g4G_EzHebnFT5zZoasWCS_EzZQ5BgnLZny9S%3Dpg%40mail.gmail.com
---
 src/backend/catalog/pg_subscription.c       | 70 +++------------------
 src/backend/commands/subscriptioncmds.c     |  4 +-
 src/backend/replication/logical/tablesync.c |  2 +-
 src/include/catalog/pg_subscription_rel.h   |  3 +-
 4 files changed, 14 insertions(+), 65 deletions(-)

diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c
index 33ae3da8ae..3d81449382 100644
--- a/src/backend/catalog/pg_subscription.c
+++ b/src/backend/catalog/pg_subscription.c
@@ -533,65 +533,14 @@ HasSubscriptionRelations(Oid subid)
 }
 
 /*
- * Get all relations for subscription.
+ * Get the relations for subscription.
  *
- * Returned list is palloc'ed in current memory context.
+ * If only_not_ready is false, return all the relations for subscription. If
+ * true, return all the relations for subscription that are not in a ready
+ * state. Returned list is palloc'ed in current memory context.
  */
 List *
-GetSubscriptionRelations(Oid subid)
-{
-	List	   *res = NIL;
-	Relation	rel;
-	HeapTuple	tup;
-	ScanKeyData skey[1];
-	SysScanDesc scan;
-
-	rel = table_open(SubscriptionRelRelationId, AccessShareLock);
-
-	ScanKeyInit(&skey[0],
-				Anum_pg_subscription_rel_srsubid,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(subid));
-
-	scan = systable_beginscan(rel, InvalidOid, false,
-							  NULL, 1, skey);
-
-	while (HeapTupleIsValid(tup = systable_getnext(scan)))
-	{
-		Form_pg_subscription_rel subrel;
-		SubscriptionRelState *relstate;
-		Datum		d;
-		bool		isnull;
-
-		subrel = (Form_pg_subscription_rel) GETSTRUCT(tup);
-
-		relstate = (SubscriptionRelState *) palloc(sizeof(SubscriptionRelState));
-		relstate->relid = subrel->srrelid;
-		relstate->state = subrel->srsubstate;
-		d = SysCacheGetAttr(SUBSCRIPTIONRELMAP, tup,
-							Anum_pg_subscription_rel_srsublsn, &isnull);
-		if (isnull)
-			relstate->lsn = InvalidXLogRecPtr;
-		else
-			relstate->lsn = DatumGetLSN(d);
-
-		res = lappend(res, relstate);
-	}
-
-	/* Cleanup */
-	systable_endscan(scan);
-	table_close(rel, AccessShareLock);
-
-	return res;
-}
-
-/*
- * Get all relations for subscription that are not in a ready state.
- *
- * Returned list is palloc'ed in current memory context.
- */
-List *
-GetSubscriptionNotReadyRelations(Oid subid)
+GetSubscriptionRelations(Oid subid, bool only_not_ready)
 {
 	List	   *res = NIL;
 	Relation	rel;
@@ -607,10 +556,11 @@ GetSubscriptionNotReadyRelations(Oid subid)
 				BTEqualStrategyNumber, F_OIDEQ,
 				ObjectIdGetDatum(subid));
 
-	ScanKeyInit(&skey[nkeys++],
-				Anum_pg_subscription_rel_srsubstate,
-				BTEqualStrategyNumber, F_CHARNE,
-				CharGetDatum(SUBREL_STATE_READY));
+	if (only_not_ready)
+		ScanKeyInit(&skey[nkeys++],
+					Anum_pg_subscription_rel_srsubstate,
+					BTEqualStrategyNumber, F_CHARNE,
+					CharGetDatum(SUBREL_STATE_READY));
 
 	scan = systable_beginscan(rel, InvalidOid, false,
 							  NULL, nkeys, skey);
diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index bd0cc0848d..f73dfb6067 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -814,7 +814,7 @@ AlterSubscription_refresh(Subscription *sub, bool copy_data,
 		pubrel_names = fetch_table_list(wrconn, sub->publications);
 
 		/* Get local table list. */
-		subrel_states = GetSubscriptionRelations(sub->oid);
+		subrel_states = GetSubscriptionRelations(sub->oid, false);
 
 		/*
 		 * Build qsorted array of local table oids for faster lookup. This can
@@ -1494,7 +1494,7 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 * the apply and tablesync workers and they can't restart because of
 	 * exclusive lock on the subscription.
 	 */
-	rstates = GetSubscriptionNotReadyRelations(subid);
+	rstates = GetSubscriptionRelations(subid, true);
 	foreach(lc, rstates)
 	{
 		SubscriptionRelState *rstate = (SubscriptionRelState *) lfirst(lc);
diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index 670c6fcada..6a01ffd273 100644
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -1479,7 +1479,7 @@ FetchTableStates(bool *started_tx)
 		}
 
 		/* Fetch all non-ready tables. */
-		rstates = GetSubscriptionNotReadyRelations(MySubscription->oid);
+		rstates = GetSubscriptionRelations(MySubscription->oid, true);
 
 		/* Allocate the tracking info in a permanent memory context. */
 		oldctx = MemoryContextSwitchTo(CacheMemoryContext);
diff --git a/src/include/catalog/pg_subscription_rel.h b/src/include/catalog/pg_subscription_rel.h
index 9df99c3418..e835c42ef7 100644
--- a/src/include/catalog/pg_subscription_rel.h
+++ b/src/include/catalog/pg_subscription_rel.h
@@ -88,7 +88,6 @@ extern char GetSubscriptionRelState(Oid subid, Oid relid, XLogRecPtr *sublsn);
 extern void RemoveSubscriptionRel(Oid subid, Oid relid);
 
 extern bool HasSubscriptionRelations(Oid subid);
-extern List *GetSubscriptionRelations(Oid subid);
-extern List *GetSubscriptionNotReadyRelations(Oid subid);
+extern List *GetSubscriptionRelations(Oid subid, bool only_not_ready);
 
 #endif							/* PG_SUBSCRIPTION_REL_H */
-- 
2.32.0

From 4172eeaef8f7890e6ff0148de65332264d039075 Mon Sep 17 00:00:00 2001
From: Vigneshwaran C <vignesh21@gmail.com>
Date: Wed, 13 Jul 2022 11:54:59 +0530
Subject: [PATCH v5] Refactor to make use of a common function for
 GetSubscriptionRelations and GetSubscriptionNotReadyRelations.

Most of the code is common between GetSubscriptionRelations and
GetSubscriptionNotReadyRelations. Added a parameter to GetSubscriptionRelations
which could provide the same functionality for GetSubscriptionRelations
and GetSubscriptionNotReadyRelations.

Author: Vignesh C
Reviewed-By: Michael Paquier, Peter Smith, Amit Kapila, Kyotaro Horiguchi
Discussion: https://www.postgresql.org/message-id/flat/CALDaNm0eW-9g4G_EzHebnFT5zZoasWCS_EzZQ5BgnLZny9S%3Dpg%40mail.gmail.com
---
 src/backend/catalog/pg_subscription.c       | 70 +++------------------
 src/backend/commands/subscriptioncmds.c     |  4 +-
 src/backend/replication/logical/tablesync.c |  2 +-
 src/include/catalog/pg_subscription_rel.h   |  3 +-
 4 files changed, 14 insertions(+), 65 deletions(-)

diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c
index 33ae3da8ae..a60fbaca26 100644
--- a/src/backend/catalog/pg_subscription.c
+++ b/src/backend/catalog/pg_subscription.c
@@ -533,65 +533,14 @@ HasSubscriptionRelations(Oid subid)
 }
 
 /*
- * Get all relations for subscription.
+ * Get the relations for the subscription.
  *
- * Returned list is palloc'ed in current memory context.
+ * If not_ready is true, return only the relations that are not in a ready
+ * state, otherwise return all the subscription relations. The returned list is
+ * palloc'ed in the current memory context.
  */
 List *
-GetSubscriptionRelations(Oid subid)
-{
-	List	   *res = NIL;
-	Relation	rel;
-	HeapTuple	tup;
-	ScanKeyData skey[1];
-	SysScanDesc scan;
-
-	rel = table_open(SubscriptionRelRelationId, AccessShareLock);
-
-	ScanKeyInit(&skey[0],
-				Anum_pg_subscription_rel_srsubid,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(subid));
-
-	scan = systable_beginscan(rel, InvalidOid, false,
-							  NULL, 1, skey);
-
-	while (HeapTupleIsValid(tup = systable_getnext(scan)))
-	{
-		Form_pg_subscription_rel subrel;
-		SubscriptionRelState *relstate;
-		Datum		d;
-		bool		isnull;
-
-		subrel = (Form_pg_subscription_rel) GETSTRUCT(tup);
-
-		relstate = (SubscriptionRelState *) palloc(sizeof(SubscriptionRelState));
-		relstate->relid = subrel->srrelid;
-		relstate->state = subrel->srsubstate;
-		d = SysCacheGetAttr(SUBSCRIPTIONRELMAP, tup,
-							Anum_pg_subscription_rel_srsublsn, &isnull);
-		if (isnull)
-			relstate->lsn = InvalidXLogRecPtr;
-		else
-			relstate->lsn = DatumGetLSN(d);
-
-		res = lappend(res, relstate);
-	}
-
-	/* Cleanup */
-	systable_endscan(scan);
-	table_close(rel, AccessShareLock);
-
-	return res;
-}
-
-/*
- * Get all relations for subscription that are not in a ready state.
- *
- * Returned list is palloc'ed in current memory context.
- */
-List *
-GetSubscriptionNotReadyRelations(Oid subid)
+GetSubscriptionRelations(Oid subid, bool not_ready)
 {
 	List	   *res = NIL;
 	Relation	rel;
@@ -607,10 +556,11 @@ GetSubscriptionNotReadyRelations(Oid subid)
 				BTEqualStrategyNumber, F_OIDEQ,
 				ObjectIdGetDatum(subid));
 
-	ScanKeyInit(&skey[nkeys++],
-				Anum_pg_subscription_rel_srsubstate,
-				BTEqualStrategyNumber, F_CHARNE,
-				CharGetDatum(SUBREL_STATE_READY));
+	if (not_ready)
+		ScanKeyInit(&skey[nkeys++],
+					Anum_pg_subscription_rel_srsubstate,
+					BTEqualStrategyNumber, F_CHARNE,
+					CharGetDatum(SUBREL_STATE_READY));
 
 	scan = systable_beginscan(rel, InvalidOid, false,
 							  NULL, nkeys, skey);
diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index bd0cc0848d..f73dfb6067 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -814,7 +814,7 @@ AlterSubscription_refresh(Subscription *sub, bool copy_data,
 		pubrel_names = fetch_table_list(wrconn, sub->publications);
 
 		/* Get local table list. */
-		subrel_states = GetSubscriptionRelations(sub->oid);
+		subrel_states = GetSubscriptionRelations(sub->oid, false);
 
 		/*
 		 * Build qsorted array of local table oids for faster lookup. This can
@@ -1494,7 +1494,7 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	 * the apply and tablesync workers and they can't restart because of
 	 * exclusive lock on the subscription.
 	 */
-	rstates = GetSubscriptionNotReadyRelations(subid);
+	rstates = GetSubscriptionRelations(subid, true);
 	foreach(lc, rstates)
 	{
 		SubscriptionRelState *rstate = (SubscriptionRelState *) lfirst(lc);
diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index 670c6fcada..6a01ffd273 100644
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -1479,7 +1479,7 @@ FetchTableStates(bool *started_tx)
 		}
 
 		/* Fetch all non-ready tables. */
-		rstates = GetSubscriptionNotReadyRelations(MySubscription->oid);
+		rstates = GetSubscriptionRelations(MySubscription->oid, true);
 
 		/* Allocate the tracking info in a permanent memory context. */
 		oldctx = MemoryContextSwitchTo(CacheMemoryContext);
diff --git a/src/include/catalog/pg_subscription_rel.h b/src/include/catalog/pg_subscription_rel.h
index 9df99c3418..8e88de7b2b 100644
--- a/src/include/catalog/pg_subscription_rel.h
+++ b/src/include/catalog/pg_subscription_rel.h
@@ -88,7 +88,6 @@ extern char GetSubscriptionRelState(Oid subid, Oid relid, XLogRecPtr *sublsn);
 extern void RemoveSubscriptionRel(Oid subid, Oid relid);
 
 extern bool HasSubscriptionRelations(Oid subid);
-extern List *GetSubscriptionRelations(Oid subid);
-extern List *GetSubscriptionNotReadyRelations(Oid subid);
+extern List *GetSubscriptionRelations(Oid subid, bool not_ready);
 
 #endif							/* PG_SUBSCRIPTION_REL_H */
-- 
2.32.0