[CF 5725] v2 - domain over virtual generated column

This branch was automatically generated by a robot using patches from an
email thread registered at:

https://commitfest.postgresql.org/patch/5725

The branch will be overwritten each time a new patch version is posted to
the thread, and also periodically to check for bitrot caused by changes
on the master branch.

Patch(es): https://www.postgresql.org/message-id/CACJufxEQopHp0ZTrKtnFXQ1U9oWd2=35oShV3TSK=roYPsC+Dw@mail.gmail.com
Author(s): Jian He

Author: Commitfest Bot

src/backend/catalog/heap.c

@@ -583,17 +583,6 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
-		/*
-		 * Prevent virtual generated columns from having a domain type.  We
-		 * would have to enforce domain constraints when columns underlying
-		 * the generated column change.  This could possibly be implemented,
-		 * but it's not.
-		 */
-		if (flags & CHKATYPE_IS_VIRTUAL)
-			ereport(ERROR,
-					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					errmsg("virtual generated column \"%s\" cannot have a domain type", attname));
-
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */

src/backend/commands/copyfrom.c

@@ -1343,11 +1343,12 @@ CopyFrom(CopyFromState cstate)
 			}
 			else
 			{
-				/* Compute stored generated columns */
+				/* Compute generated columns */
 				if (resultRelInfo->ri_RelationDesc->rd_att->constr &&
-					resultRelInfo->ri_RelationDesc->rd_att->constr->has_generated_stored)
-					ExecComputeStoredGenerated(resultRelInfo, estate, myslot,
-											   CMD_INSERT);
+					(resultRelInfo->ri_RelationDesc->rd_att->constr->has_generated_stored ||
+					 resultRelInfo->ri_RelationDesc->rd_att->constr->has_generated_virtual))
+					ExecComputeGenerated(resultRelInfo, estate, myslot,
+										 CMD_INSERT);
 
 				/*
 				 * If the target is a plain table, check the constraints of

src/backend/commands/tablecmds.c

@@ -6009,7 +6009,7 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode,
 			 * rebuild data.
 			 */
 			if (tab->constraints != NIL || tab->verify_new_notnull ||
-				tab->partition_constraint != NULL)
+				tab->newvals || tab->partition_constraint != NULL)
 				ATRewriteTable(tab, InvalidOid);
 
 			/*
@@ -6129,6 +6129,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 	BulkInsertState bistate;
 	int			ti_options;
 	ExprState  *partqualstate = NULL;
+	List		*domain_virtual_attrs = NIL;
 
 	/*
 	 * Open the relation(s).  We have surely already locked the existing
@@ -6204,6 +6205,16 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 
 		/* expr already planned */
 		ex->exprstate = ExecInitExpr((Expr *) ex->expr, NULL);
+		if (tab->rewrite == 0 && ex->is_generated)
+		{
+			Form_pg_attribute attr = TupleDescAttr(newTupDesc, ex->attnum - 1);
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+				DomainHasConstraints(attr->atttypid))
+			{
+				Assert(!attr->attisdropped);
+				domain_virtual_attrs = lappend_int(domain_virtual_attrs, attr->attnum);
+			}
+		}
 	}
 
 	notnull_attrs = notnull_virtual_attrs = NIL;
@@ -6239,6 +6250,13 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 			needscan = true;
 	}
 
+	/*
+	 * We need verify domain constraints on the virtual generated column are
+	 * satisfied, which requires table scan.
+	*/
+	if (domain_virtual_attrs != NIL)
+		needscan = true;
+
 	if (newrel || needscan)
 	{
 		ExprContext *econtext;
@@ -6497,6 +6515,35 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 				}
 			}
 
+			/*
+			 * domain_virtual_attrs is a list of newly added columns that are
+			 * virtual generated columns with a domain data type and associated
+			 * constraints. We need to verify that these domain constraints are
+			 * satisfied.
+			*/
+			if (domain_virtual_attrs != NIL)
+			{
+				Assert(tab->rewrite == 0);
+
+				foreach(l, tab->newvals)
+				{
+					NewColumnValue *ex = lfirst(l);
+
+					if (!ex->is_generated)
+						continue;
+
+					if(list_member_int(domain_virtual_attrs, ex->attnum) &&
+					   !ExecCheck(ex->exprstate, econtext))
+					{
+						Form_pg_attribute attr = TupleDescAttr(newTupDesc, ex->attnum - 1);
+						ereport(ERROR,
+								errcode(ERRCODE_CHECK_VIOLATION),
+								errmsg("value for domain %s is violated by some row",
+								format_type_be(attr->atttypid)));
+					}
+				}
+			}
+
 			if (partqualstate && !ExecCheck(partqualstate, econtext))
 			{
 				if (tab->validate_default)