1 files changed, 38 insertions, 13 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index e74fb1f4691..83a881eff38 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -714,6 +714,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 			rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
 			rawEnt->attnum = attnum;
 			rawEnt->raw_default = colDef->raw_default;
+			rawEnt->missingMode = false;
 			rawDefaults = lappend(rawDefaults, rawEnt);
 			attr->atthasdef = true;
 		}
@@ -4682,7 +4683,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 			{
 				int			attn = lfirst_int(l);
 
-				if (heap_attisnull(tuple, attn + 1))
+				if (heap_attisnull(tuple, attn + 1, newTupDesc))
 				{
 					Form_pg_attribute attr = TupleDescAttr(newTupDesc, attn);
 
@@ -4785,7 +4786,7 @@ ATGetQueueEntry(List **wqueue, Relation rel)
 	tab = (AlteredTableInfo *) palloc0(sizeof(AlteredTableInfo));
 	tab->relid = relid;
 	tab->relkind = rel->rd_rel->relkind;
-	tab->oldDesc = CreateTupleDescCopy(RelationGetDescr(rel));
+	tab->oldDesc = CreateTupleDescCopyConstr(RelationGetDescr(rel));
 	tab->newrelpersistence = RELPERSISTENCE_PERMANENT;
 	tab->chgPersistence = false;
 
@@ -5404,6 +5405,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	attribute.attalign = tform->typalign;
 	attribute.attnotnull = colDef->is_not_null;
 	attribute.atthasdef = false;
+	attribute.atthasmissing = false;
 	attribute.attidentity = colDef->identity;
 	attribute.attisdropped = false;
 	attribute.attislocal = colDef->is_local;
@@ -5449,6 +5451,13 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		rawEnt->raw_default = copyObject(colDef->raw_default);
 
 		/*
+		 * Attempt to skip a complete table rewrite by storing the specified
+		 * DEFAULT value outside of the heap.  This may be disabled inside
+		 * AddRelationNewConstraints if the optimization cannot be applied.
+		 */
+		rawEnt->missingMode = true;
+
+		/*
 		 * This function is intended for CREATE TABLE, so it processes a
 		 * _list_ of defaults, but we just do one.
 		 */
@@ -5457,6 +5466,13 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 
 		/* Make the additional catalog changes visible */
 		CommandCounterIncrement();
+
+		/*
+		 * Did the request for a missing value work? If not we'll have to do
+		 * a rewrite
+		 */
+		if (!rawEnt->missingMode)
+			tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
 	}
 
 	/*
@@ -5502,6 +5518,9 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			nve->typeId = typeOid;
 
 			defval = (Expr *) nve;
+
+			/* must do a rewrite for identity columns */
+			tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
 		}
 		else
 			defval = (Expr *) build_column_default(rel, attribute.attnum);
@@ -5537,16 +5556,21 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			newval->expr = expression_planner(defval);
 
 			tab->newvals = lappend(tab->newvals, newval);
-			tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
 		}
 
-		/*
-		 * If the new column is NOT NULL, tell Phase 3 it needs to test that.
-		 * (Note we don't do this for an OID column.  OID will be marked not
-		 * null, but since it's filled specially, there's no need to test
-		 * anything.)
-		 */
-		tab->new_notnull |= colDef->is_not_null;
+		if (DomainHasConstraints(typeOid))
+			tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+
+		if (!TupleDescAttr(rel->rd_att, attribute.attnum - 1)->atthasmissing)
+		{
+			/*
+			 * If the new column is NOT NULL, and there is no missing value,
+			 * tell Phase 3 it needs to test that. (Note we don't do this for
+			 * an OID column.  OID will be marked not null, but since it's
+			 * filled specially, there's no need to test anything.)
+			 */
+			tab->new_notnull |= colDef->is_not_null;
+		}
 	}
 
 	/*
@@ -6022,6 +6046,7 @@ ATExecColumnDefault(Relation rel, const char *colName,
 		rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
 		rawEnt->attnum = attnum;
 		rawEnt->raw_default = newDefault;
+		rawEnt->missingMode = false;
 
 		/*
 		 * This function is intended for CREATE TABLE, so it processes a
@@ -8109,8 +8134,8 @@ transformFkeyCheckAttrs(Relation pkrel,
 		if (indexStruct->indnatts == numattrs &&
 			indexStruct->indisunique &&
 			IndexIsValid(indexStruct) &&
-			heap_attisnull(indexTuple, Anum_pg_index_indpred) &&
-			heap_attisnull(indexTuple, Anum_pg_index_indexprs))
+			heap_attisnull(indexTuple, Anum_pg_index_indpred, NULL) &&
+			heap_attisnull(indexTuple, Anum_pg_index_indexprs, NULL))
 		{
 			Datum		indclassDatum;
 			bool		isnull;
@@ -9516,7 +9541,7 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
 		RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, true,
 						  true);
 
-		StoreAttrDefault(rel, attnum, defaultexpr, true);
+		StoreAttrDefault(rel, attnum, defaultexpr, true, false);
 	}
 
 	ObjectAddressSubSet(address, RelationRelationId,