commit 0c0dcbf03de108cd923cb771fa5fa2aed781a71b
Author: Masahiko Sawada <sawada.mshk@gmail.com>
Date:   Mon Apr 17 17:38:56 2017 +0900

    Add NOT NULL constraint to all columns of pg_subscription.

diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c
index a183850..3cc762a 100644
--- a/src/backend/catalog/pg_subscription.c
+++ b/src/backend/catalog/pg_subscription.c
@@ -74,7 +74,6 @@ GetSubscription(Oid subid, bool missing_ok)
 							tup,
 							Anum_pg_subscription_subconninfo,
 							&isnull);
-	Assert(!isnull);
 	sub->conninfo = TextDatumGetCString(datum);
 
 	/* Get slotname */
@@ -82,7 +81,6 @@ GetSubscription(Oid subid, bool missing_ok)
 							tup,
 							Anum_pg_subscription_subslotname,
 							&isnull);
-	Assert(!isnull);
 	sub->slotname = pstrdup(NameStr(*DatumGetName(datum)));
 
 	/* Get synccommit */
@@ -90,7 +88,6 @@ GetSubscription(Oid subid, bool missing_ok)
 							tup,
 							Anum_pg_subscription_subsynccommit,
 							&isnull);
-	Assert(!isnull);
 	sub->synccommit = TextDatumGetCString(datum);
 
 	/* Get publications */
@@ -98,7 +95,6 @@ GetSubscription(Oid subid, bool missing_ok)
 							tup,
 							Anum_pg_subscription_subpublications,
 							&isnull);
-	Assert(!isnull);
 	sub->publications = textarray_to_stringlist(DatumGetArrayTypeP(datum));
 
 	ReleaseSysCache(tup);
diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 519c684..1ef4fa3 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -796,19 +796,16 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 	/* Get subname */
 	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
 							Anum_pg_subscription_subname, &isnull);
-	Assert(!isnull);
 	subname = pstrdup(NameStr(*DatumGetName(datum)));
 
 	/* Get conninfo */
 	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
 							Anum_pg_subscription_subconninfo, &isnull);
-	Assert(!isnull);
 	conninfo = TextDatumGetCString(datum);
 
 	/* Get slotname */
 	datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup,
 							Anum_pg_subscription_subslotname, &isnull);
-	Assert(!isnull);
 	slotname = pstrdup(NameStr(*DatumGetName(datum)));
 
 	ObjectAddressSet(myself, SubscriptionRelationId, subid);
diff --git a/src/include/catalog/pg_subscription.h b/src/include/catalog/pg_subscription.h
index fae542b..a069772 100644
--- a/src/include/catalog/pg_subscription.h
+++ b/src/include/catalog/pg_subscription.h
@@ -41,10 +41,10 @@ CATALOG(pg_subscription,6100) BKI_SHARED_RELATION BKI_ROWTYPE_OID(6101) BKI_SCHE
 								 * (the worker should be running) */
 
 #ifdef CATALOG_VARLEN			/* variable-length fields start here */
-	text		subconninfo;	/* Connection string to the publisher */
-	NameData	subslotname;	/* Slot name on publisher */
-	text		subsynccommit;	/* Synchronous commit setting for worker */
-	text		subpublications[1];	/* List of publications subscribed to */
+	text		subconninfo BKI_FORCE_NOT_NULL;	/* Connection string to the publisher */
+	NameData	subslotname BKI_FORCE_NOT_NULL;	/* Slot name on publisher */
+	text		subsynccommit BKI_FORCE_NOT_NULL;	/* Synchronous commit setting for worker */
+	text		subpublications[1] BKI_FORCE_NOT_NULL;	/* List of publications subscribed to */
 #endif
 } FormData_pg_subscription;