tablecmds.c 94.7 KB
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/*-------------------------------------------------------------------------
 *
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 * tablecmds.c
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 *	  Commands for creating and altering table structures and settings
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 *
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 * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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 * Portions Copyright (c) 1994, Regents of the University of California
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 *
 *
 * IDENTIFICATION
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 *	  $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.29 2002/08/15 16:36:02 momjian Exp $
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 *
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 *-------------------------------------------------------------------------
 */
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#include "postgres.h"

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#include "access/genam.h"
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#include "access/tuptoaster.h"
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#include "catalog/catalog.h"
#include "catalog/catname.h"
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#include "catalog/dependency.h"
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#include "catalog/heap.h"
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#include "catalog/index.h"
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#include "catalog/indexing.h"
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#include "catalog/namespace.h"
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#include "catalog/pg_constraint.h"
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#include "catalog/pg_inherits.h"
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#include "catalog/pg_namespace.h"
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#include "catalog/pg_opclass.h"
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#include "catalog/pg_trigger.h"
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#include "catalog/pg_type.h"
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#include "commands/tablecmds.h"
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#include "commands/trigger.h"
#include "executor/executor.h"
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#include "miscadmin.h"
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#include "nodes/makefuncs.h"
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#include "optimizer/clauses.h"
#include "optimizer/planmain.h"
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#include "optimizer/prep.h"
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#include "parser/gramparse.h"
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#include "parser/parse_coerce.h"
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#include "parser/parse_expr.h"
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#include "parser/parse_relation.h"
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#include "parser/parse_type.h"
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#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
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#include "utils/relcache.h"
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static List *MergeAttributes(List *schema, List *supers, bool istemp,
				List **supOids, List **supconstr, bool *supHasOids);
static bool change_varattnos_of_a_node(Node *node, const AttrNumber *newattno);
static void StoreCatalogInheritance(Oid relationId, List *supers);
static int	findAttrByName(const char *attributeName, List *schema);
static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
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static void CheckTupleType(Form_pg_class tuple_class);
static bool needs_toast_table(Relation rel);
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static void validateForeignKeyConstraint(FkConstraint *fkconstraint,
										 Relation rel, Relation pkrel);
static Oid	createForeignKeyConstraint(Relation rel, Relation pkrel,
									   FkConstraint *fkconstraint);
static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
									 Oid constrOid);
static char *fkMatchTypeToString(char match_type);
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/* Used by attribute and relation renaming routines: */
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#define RI_TRIGGER_PK	1		/* is a trigger on the PK relation */
#define RI_TRIGGER_FK	2		/* is a trigger on the FK relation */
#define RI_TRIGGER_NONE 0		/* is not an RI trigger function */
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static int	ri_trigger_type(Oid tgfoid);
static void update_ri_trigger_args(Oid relid,
					   const char *oldname,
					   const char *newname,
					   bool fk_scan,
					   bool update_relname);
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/* ----------------------------------------------------------------
 *		DefineRelation
 *				Creates a new relation.
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 *
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 * If successful, returns the OID of the new relation.
 * ----------------------------------------------------------------
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 */
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Oid
DefineRelation(CreateStmt *stmt, char relkind)
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{
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	char		relname[NAMEDATALEN];
	Oid			namespaceId;
	List	   *schema = stmt->tableElts;
	int			numberOfAttributes;
	Oid			relationId;
	Relation	rel;
	TupleDesc	descriptor;
	List	   *inheritOids;
	List	   *old_constraints;
	bool		parentHasOids;
	List	   *rawDefaults;
	List	   *listptr;
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	int			i;
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	AttrNumber	attnum;
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	/*
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	 * Truncate relname to appropriate length (probably a waste of time,
	 * as parser should have done this already).
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	 */
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	StrNCpy(relname, stmt->relation->relname, NAMEDATALEN);
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	/*
	 * Look up the namespace in which we are supposed to create the
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	 * relation.  Check we have permission to create there.
	 * Skip check if bootstrapping, since permissions machinery may not
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	 * be working yet.
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	 */
	namespaceId = RangeVarGetCreationNamespace(stmt->relation);
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	if (!IsBootstrapProcessingMode())
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	{
		AclResult	aclresult;

		aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
										  ACL_CREATE);
		if (aclresult != ACLCHECK_OK)
			aclcheck_error(aclresult, get_namespace_name(namespaceId));
	}

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	/*
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	 * Look up inheritance ancestors and generate relation schema,
	 * including inherited attributes.
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	 */
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	schema = MergeAttributes(schema, stmt->inhRelations,
							 stmt->relation->istemp,
							 &inheritOids, &old_constraints, &parentHasOids);
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	numberOfAttributes = length(schema);
	if (numberOfAttributes <= 0)
		elog(ERROR, "DefineRelation: please inherit from a relation or define an attribute");
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	/*
	 * Create a relation descriptor from the relation schema and create
	 * the relation.  Note that in this stage only inherited (pre-cooked)
	 * defaults and constraints will be included into the new relation.
	 * (BuildDescForRelation takes care of the inherited defaults, but we
	 * have to copy inherited constraints here.)
	 */
	descriptor = BuildDescForRelation(schema);
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	descriptor->tdhasoid = BoolToHasOid(stmt->hasoids || parentHasOids);
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	if (old_constraints != NIL)
	{
		ConstrCheck *check = (ConstrCheck *) palloc(length(old_constraints) *
													sizeof(ConstrCheck));
		int			ncheck = 0;
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		int			constr_name_ctr = 0;
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		foreach(listptr, old_constraints)
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		{
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			Constraint *cdef = (Constraint *) lfirst(listptr);
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			if (cdef->contype != CONSTR_CHECK)
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				continue;
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			if (cdef->name != NULL)
			{
				for (i = 0; i < ncheck; i++)
				{
					if (strcmp(check[i].ccname, cdef->name) == 0)
						elog(ERROR, "Duplicate CHECK constraint name: '%s'",
							 cdef->name);
				}
				check[ncheck].ccname = cdef->name;
			}
			else
			{
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				/*
				 * Generate a constraint name.  NB: this should match the
				 * form of names that GenerateConstraintName() may produce
				 * for names added later.  We are assured that there is
				 * no name conflict, because MergeAttributes() did not pass
				 * back any names of this form.
				 */
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				check[ncheck].ccname = (char *) palloc(NAMEDATALEN);
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				snprintf(check[ncheck].ccname, NAMEDATALEN, "$%d",
						 ++constr_name_ctr);
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			}
			Assert(cdef->raw_expr == NULL && cdef->cooked_expr != NULL);
			check[ncheck].ccbin = pstrdup(cdef->cooked_expr);
			ncheck++;
		}
		if (ncheck > 0)
		{
			if (descriptor->constr == NULL)
			{
				descriptor->constr = (TupleConstr *) palloc(sizeof(TupleConstr));
				descriptor->constr->defval = NULL;
				descriptor->constr->num_defval = 0;
				descriptor->constr->has_not_null = false;
			}
			descriptor->constr->num_check = ncheck;
			descriptor->constr->check = check;
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		}
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	}

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	relationId = heap_create_with_catalog(relname,
										  namespaceId,
										  descriptor,
										  relkind,
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										  false,
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										  stmt->hasoids || parentHasOids,
										  allowSystemTableMods);

	StoreCatalogInheritance(relationId, inheritOids);

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	/*
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	 * We must bump the command counter to make the newly-created relation
	 * tuple visible for opening.
	 */
	CommandCounterIncrement();

	/*
	 * Open the new relation and acquire exclusive lock on it.	This isn't
	 * really necessary for locking out other backends (since they can't
	 * see the new rel anyway until we commit), but it keeps the lock
	 * manager from complaining about deadlock risks.
	 */
	rel = heap_open(relationId, AccessExclusiveLock);

	/*
	 * Now add any newly specified column default values and CHECK
	 * constraints to the new relation.  These are passed to us in the
	 * form of raw parsetrees; we need to transform them to executable
	 * expression trees before they can be added. The most convenient way
	 * to do that is to apply the parser's transformExpr routine, but
	 * transformExpr doesn't work unless we have a pre-existing relation.
	 * So, the transformation has to be postponed to this final step of
	 * CREATE TABLE.
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	 *
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	 * Another task that's conveniently done at this step is to add
	 * dependency links between columns and supporting relations (such
	 * as SERIAL sequences).
	 *
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	 * First, scan schema to find new column defaults.
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	 */
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	rawDefaults = NIL;
	attnum = 0;
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	foreach(listptr, schema)
	{
		ColumnDef  *colDef = lfirst(listptr);
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		attnum++;
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		if (colDef->raw_default != NULL)
		{
			RawColumnDefault *rawEnt;

			Assert(colDef->cooked_default == NULL);

			rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
			rawEnt->attnum = attnum;
			rawEnt->raw_default = colDef->raw_default;
			rawDefaults = lappend(rawDefaults, rawEnt);
		}
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		if (colDef->support != NULL)
		{
			/* Create dependency for supporting relation for this column */
			ObjectAddress	colobject,
						suppobject;

			colobject.classId = RelOid_pg_class;
			colobject.objectId = relationId;
			colobject.objectSubId = attnum;
			suppobject.classId = RelOid_pg_class;
			suppobject.objectId = RangeVarGetRelid(colDef->support, false);
			suppobject.objectSubId = 0;
			recordDependencyOn(&suppobject, &colobject, DEPENDENCY_INTERNAL);
		}
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	}
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	/*
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	 * Parse and add the defaults/constraints, if any.
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	 */
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	if (rawDefaults || stmt->constraints)
		AddRelationRawConstraints(rel, rawDefaults, stmt->constraints);
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	/*
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	 * Clean up.  We keep lock on new relation (although it shouldn't be
	 * visible to anyone else anyway, until commit).
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	 */
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	heap_close(rel, NoLock);
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	return relationId;
}
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/*
 * RemoveRelation
 *		Deletes a relation.
 */
void
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RemoveRelation(const RangeVar *relation, DropBehavior behavior)
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{
	Oid			relOid;
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	ObjectAddress object;
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	relOid = RangeVarGetRelid(relation, false);
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	object.classId = RelOid_pg_class;
	object.objectId = relOid;
	object.objectSubId = 0;

	performDeletion(&object, behavior);
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}

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/*
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 * TruncateRelation
 *				  Removes all the rows from a relation
 *
 * Exceptions:
 *				  BadArg if name is invalid
 *
 * Note:
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 *				  Rows are removed, indexes are truncated and reconstructed.
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 */
void
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TruncateRelation(const RangeVar *relation)
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{
	Relation	rel;
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	Oid			relid;
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	/* Grab exclusive lock in preparation for truncate */
	rel = heap_openrv(relation, AccessExclusiveLock);
	relid = RelationGetRelid(rel);
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	if (rel->rd_rel->relkind == RELKIND_SEQUENCE)
		elog(ERROR, "TRUNCATE cannot be used on sequences. '%s' is a sequence",
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			 RelationGetRelationName(rel));

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	if (rel->rd_rel->relkind == RELKIND_VIEW)
		elog(ERROR, "TRUNCATE cannot be used on views. '%s' is a view",
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			 RelationGetRelationName(rel));

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	if (rel->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
		elog(ERROR, "TRUNCATE cannot be used on type relations. '%s' is a type",
			 RelationGetRelationName(rel));

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	if (!allowSystemTableMods && IsSystemRelation(rel))
		elog(ERROR, "TRUNCATE cannot be used on system tables. '%s' is a system table",
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			 RelationGetRelationName(rel));

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	if (!pg_class_ownercheck(relid, GetUserId()))
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		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
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	/* Keep the lock until transaction commit */
	heap_close(rel, NoLock);
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	heap_truncate(relid);
}
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/*----------
 * MergeAttributes
 *		Returns new schema given initial schema and superclasses.
 *
 * Input arguments:
 * 'schema' is the column/attribute definition for the table. (It's a list
 *		of ColumnDef's.) It is destructively changed.
 * 'supers' is a list of names (as RangeVar nodes) of parent relations.
 * 'istemp' is TRUE if we are creating a temp relation.
 *
 * Output arguments:
 * 'supOids' receives an integer list of the OIDs of the parent relations.
 * 'supconstr' receives a list of constraints belonging to the parents,
 *		updated as necessary to be valid for the child.
 * 'supHasOids' is set TRUE if any parent has OIDs, else it is set FALSE.
 *
 * Return value:
 * Completed schema list.
 *
 * Notes:
 *	  The order in which the attributes are inherited is very important.
 *	  Intuitively, the inherited attributes should come first. If a table
 *	  inherits from multiple parents, the order of those attributes are
 *	  according to the order of the parents specified in CREATE TABLE.
 *
 *	  Here's an example:
 *
 *		create table person (name text, age int4, location point);
 *		create table emp (salary int4, manager text) inherits(person);
 *		create table student (gpa float8) inherits (person);
 *		create table stud_emp (percent int4) inherits (emp, student);
 *
 *	  The order of the attributes of stud_emp is:
 *
 *							person {1:name, 2:age, 3:location}
 *							/	 \
 *			   {6:gpa}	student   emp {4:salary, 5:manager}
 *							\	 /
 *						   stud_emp {7:percent}
 *
 *	   If the same attribute name appears multiple times, then it appears
 *	   in the result table in the proper location for its first appearance.
 *
 *	   Constraints (including NOT NULL constraints) for the child table
 *	   are the union of all relevant constraints, from both the child schema
 *	   and parent tables.
 *
 *	   The default value for a child column is defined as:
 *		(1) If the child schema specifies a default, that value is used.
 *		(2) If neither the child nor any parent specifies a default, then
 *			the column will not have a default.
 *		(3) If conflicting defaults are inherited from different parents
 *			(and not overridden by the child), an error is raised.
 *		(4) Otherwise the inherited default is used.
 *		Rule (3) is new in Postgres 7.1; in earlier releases you got a
 *		rather arbitrary choice of which parent default to use.
 *----------
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 */
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static List *
MergeAttributes(List *schema, List *supers, bool istemp,
				List **supOids, List **supconstr, bool *supHasOids)
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{
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	List	   *entry;
	List	   *inhSchema = NIL;
	List	   *parentOids = NIL;
	List	   *constraints = NIL;
	bool		parentHasOids = false;
	bool		have_bogus_defaults = false;
	char	   *bogus_marker = "Bogus!";		/* marks conflicting
												 * defaults */
	int			child_attno;
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	/*
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	 * Check for duplicate names in the explicit list of attributes.
	 *
	 * Although we might consider merging such entries in the same way that
	 * we handle name conflicts for inherited attributes, it seems to make
	 * more sense to assume such conflicts are errors.
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	 */
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	foreach(entry, schema)
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	{
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		ColumnDef  *coldef = lfirst(entry);
		List	   *rest;
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		foreach(rest, lnext(entry))
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		{
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			ColumnDef  *restdef = lfirst(rest);
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			if (strcmp(coldef->colname, restdef->colname) == 0)
				elog(ERROR, "CREATE TABLE: attribute \"%s\" duplicated",
					 coldef->colname);
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		}
	}

	/*
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	 * Scan the parents left-to-right, and merge their attributes to form
	 * a list of inherited attributes (inhSchema).	Also check to see if
	 * we need to inherit an OID column.
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	 */
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	child_attno = 0;
	foreach(entry, supers)
	{
		RangeVar   *parent = (RangeVar *) lfirst(entry);
		Relation	relation;
		TupleDesc	tupleDesc;
		TupleConstr *constr;
		AttrNumber *newattno;
		AttrNumber	parent_attno;
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		relation = heap_openrv(parent, AccessShareLock);
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		if (relation->rd_rel->relkind != RELKIND_RELATION)
			elog(ERROR, "CREATE TABLE: inherited relation \"%s\" is not a table",
				 parent->relname);
		/* Permanent rels cannot inherit from temporary ones */
		if (!istemp && isTempNamespace(RelationGetNamespace(relation)))
			elog(ERROR, "CREATE TABLE: cannot inherit from temp relation \"%s\"",
				 parent->relname);
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		/*
		 * We should have an UNDER permission flag for this, but for now,
		 * demand that creator of a child table own the parent.
		 */
		if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId()))
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			aclcheck_error(ACLCHECK_NOT_OWNER,
						   RelationGetRelationName(relation));
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		/*
		 * Reject duplications in the list of parents.
		 */
		if (intMember(RelationGetRelid(relation), parentOids))
			elog(ERROR, "CREATE TABLE: inherited relation \"%s\" duplicated",
				 parent->relname);
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		parentOids = lappendi(parentOids, RelationGetRelid(relation));
		setRelhassubclassInRelation(RelationGetRelid(relation), true);
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		parentHasOids |= relation->rd_rel->relhasoids;
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		tupleDesc = RelationGetDescr(relation);
		constr = tupleDesc->constr;
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		/*
		 * newattno[] will contain the child-table attribute numbers for
		 * the attributes of this parent table.  (They are not the same
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		 * for parents after the first one, nor if we have dropped columns.)
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		 */
		newattno = (AttrNumber *) palloc(tupleDesc->natts * sizeof(AttrNumber));
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		for (parent_attno = 1; parent_attno <= tupleDesc->natts;
			 parent_attno++)
		{
			Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
			char	   *attributeName = NameStr(attribute->attname);
			int			exist_attno;
			ColumnDef  *def;
			TypeName   *typename;
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			/*
			 * Ignore dropped columns in the parent.
			 */
			if (attribute->attisdropped)
			{
				/* 
				 * change_varattnos_of_a_node asserts that this is greater than
				 * zero, so if anything tries to use it, we should find out.
				 */
				newattno[parent_attno - 1] = 0;
				continue;
			}

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			/*
			 * Does it conflict with some previously inherited column?
			 */
			exist_attno = findAttrByName(attributeName, inhSchema);
			if (exist_attno > 0)
			{
				/*
				 * Yes, try to merge the two column definitions. They must
				 * have the same type and typmod.
				 */
				elog(NOTICE, "CREATE TABLE: merging multiple inherited definitions of attribute \"%s\"",
					 attributeName);
				def = (ColumnDef *) nth(exist_attno - 1, inhSchema);
				if (typenameTypeId(def->typename) != attribute->atttypid ||
					def->typename->typmod != attribute->atttypmod)
					elog(ERROR, "CREATE TABLE: inherited attribute \"%s\" type conflict (%s and %s)",
						 attributeName,
						 TypeNameToString(def->typename),
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						 format_type_be(attribute->atttypid));
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				/* Merge of NOT NULL constraints = OR 'em together */
				def->is_not_null |= attribute->attnotnull;
				/* Default and other constraints are handled below */
				newattno[parent_attno - 1] = exist_attno;
			}
			else
			{
				/*
				 * No, create a new inherited column
				 */
				def = makeNode(ColumnDef);
				def->colname = pstrdup(attributeName);
				typename = makeNode(TypeName);
				typename->typeid = attribute->atttypid;
				typename->typmod = attribute->atttypmod;
				def->typename = typename;
				def->is_not_null = attribute->attnotnull;
				def->raw_default = NULL;
				def->cooked_default = NULL;
				def->constraints = NIL;
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				def->support = NULL;
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				inhSchema = lappend(inhSchema, def);
				newattno[parent_attno - 1] = ++child_attno;
			}
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			/*
			 * Copy default if any
			 */
			if (attribute->atthasdef)
			{
				char	   *this_default = NULL;
				AttrDefault *attrdef;
				int			i;
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				/* Find default in constraint structure */
				Assert(constr != NULL);
				attrdef = constr->defval;
				for (i = 0; i < constr->num_defval; i++)
				{
					if (attrdef[i].adnum == parent_attno)
					{
						this_default = attrdef[i].adbin;
						break;
					}
				}
				Assert(this_default != NULL);
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				/*
				 * If default expr could contain any vars, we'd need to
				 * fix 'em, but it can't; so default is ready to apply to
				 * child.
				 *
				 * If we already had a default from some prior parent, check
				 * to see if they are the same.  If so, no problem; if
				 * not, mark the column as having a bogus default. Below,
				 * we will complain if the bogus default isn't overridden
				 * by the child schema.
				 */
				Assert(def->raw_default == NULL);
				if (def->cooked_default == NULL)
					def->cooked_default = pstrdup(this_default);
				else if (strcmp(def->cooked_default, this_default) != 0)
				{
					def->cooked_default = bogus_marker;
					have_bogus_defaults = true;
				}
			}
		}
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		/*
		 * Now copy the constraints of this parent, adjusting attnos using
		 * the completed newattno[] map
		 */
		if (constr && constr->num_check > 0)
		{
			ConstrCheck *check = constr->check;
			int			i;
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			for (i = 0; i < constr->num_check; i++)
			{
				Constraint *cdef = makeNode(Constraint);
				Node	   *expr;
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638
				cdef->contype = CONSTR_CHECK;
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				/*
				 * Do not inherit generated constraint names, since they
				 * might conflict across multiple inheritance parents.
				 * (But conflicts between user-assigned names will cause
				 * an error.)
				 */
				if (ConstraintNameIsGenerated(check[i].ccname))
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					cdef->name = NULL;
				else
					cdef->name = pstrdup(check[i].ccname);
				cdef->raw_expr = NULL;
				/* adjust varattnos of ccbin here */
				expr = stringToNode(check[i].ccbin);
				change_varattnos_of_a_node(expr, newattno);
				cdef->cooked_expr = nodeToString(expr);
				constraints = lappend(constraints, cdef);
			}
		}
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		pfree(newattno);
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		/*
		 * Close the parent rel, but keep our AccessShareLock on it until
		 * xact commit.  That will prevent someone else from deleting or
		 * ALTERing the parent before the child is committed.
		 */
		heap_close(relation, NoLock);
	}
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668
	/*
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	 * If we had no inherited attributes, the result schema is just the
	 * explicitly declared columns.  Otherwise, we need to merge the
	 * declared columns into the inherited schema list.
672
	 */
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	if (inhSchema != NIL)
	{
		foreach(entry, schema)
		{
			ColumnDef  *newdef = lfirst(entry);
			char	   *attributeName = newdef->colname;
			int			exist_attno;
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			/*
			 * Does it conflict with some previously inherited column?
			 */
			exist_attno = findAttrByName(attributeName, inhSchema);
			if (exist_attno > 0)
			{
				ColumnDef  *def;
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				/*
				 * Yes, try to merge the two column definitions. They must
				 * have the same type and typmod.
				 */
				elog(NOTICE, "CREATE TABLE: merging attribute \"%s\" with inherited definition",
					 attributeName);
				def = (ColumnDef *) nth(exist_attno - 1, inhSchema);
				if (typenameTypeId(def->typename) != typenameTypeId(newdef->typename) ||
					def->typename->typmod != newdef->typename->typmod)
					elog(ERROR, "CREATE TABLE: attribute \"%s\" type conflict (%s and %s)",
						 attributeName,
						 TypeNameToString(def->typename),
						 TypeNameToString(newdef->typename));
				/* Merge of NOT NULL constraints = OR 'em together */
				def->is_not_null |= newdef->is_not_null;
				/* If new def has a default, override previous default */
				if (newdef->raw_default != NULL)
				{
					def->raw_default = newdef->raw_default;
					def->cooked_default = newdef->cooked_default;
				}
			}
			else
			{
				/*
				 * No, attach new column to result schema
				 */
				inhSchema = lappend(inhSchema, newdef);
			}
		}

		schema = inhSchema;
	}
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	/*
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	 * If we found any conflicting parent default values, check to make
	 * sure they were overridden by the child.
726
	 */
727
	if (have_bogus_defaults)
728
	{
729
		foreach(entry, schema)
730
		{
731
			ColumnDef  *def = lfirst(entry);
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			if (def->cooked_default == bogus_marker)
				elog(ERROR, "CREATE TABLE: attribute \"%s\" inherits conflicting default values"
					 "\n\tTo resolve the conflict, specify a default explicitly",
					 def->colname);
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		}
	}

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	*supOids = parentOids;
	*supconstr = constraints;
	*supHasOids = parentHasOids;
	return schema;
}
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/*
 * complementary static functions for MergeAttributes().
 *
749
 * Varattnos of pg_constraint.conbin must be rewritten when subclasses inherit
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 * constraints from parent classes, since the inherited attributes could
 * be given different column numbers in multiple-inheritance cases.
 *
 * Note that the passed node tree is modified in place!
 */
static bool
change_varattnos_walker(Node *node, const AttrNumber *newattno)
{
	if (node == NULL)
		return false;
	if (IsA(node, Var))
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	{
762
		Var		   *var = (Var *) node;
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		if (var->varlevelsup == 0 && var->varno == 1 &&
			var->varattno > 0)
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		{
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			/*
			 * ??? the following may be a problem when the node is
			 * multiply referenced though stringToNode() doesn't create
			 * such a node currently.
			 */
			Assert(newattno[var->varattno - 1] > 0);
			var->varattno = newattno[var->varattno - 1];
774
		}
775
		return false;
776
	}
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	return expression_tree_walker(node, change_varattnos_walker,
								  (void *) newattno);
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}

781 782
static bool
change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
783
{
784
	return change_varattnos_walker(node, newattno);
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}

787
/*
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 * StoreCatalogInheritance
 *		Updates the system catalogs with proper inheritance information.
 *
 * supers is an integer list of the OIDs of the new relation's direct
 * ancestors.  NB: it is destructively changed to include indirect ancestors.
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 */
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static void
StoreCatalogInheritance(Oid relationId, List *supers)
796
{
797 798 799 800
	Relation	relation;
	TupleDesc	desc;
	int16		seqNumber;
	List	   *entry;
801
	HeapTuple	tuple;
802

803
	/*
804
	 * sanity checks
805
	 */
806
	AssertArg(OidIsValid(relationId));
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	if (supers == NIL)
		return;
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	/*
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	 * Store INHERITS information in pg_inherits using direct ancestors only.
	 * Also enter dependencies on the direct ancestors.
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	 */
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	relation = heap_openr(InheritsRelationName, RowExclusiveLock);
	desc = RelationGetDescr(relation);
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	seqNumber = 1;
	foreach(entry, supers)
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	{
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		Oid			entryOid = lfirsti(entry);
		Datum		datum[Natts_pg_inherits];
		char		nullarr[Natts_pg_inherits];
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		ObjectAddress childobject,
					parentobject;
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		datum[0] = ObjectIdGetDatum(relationId);		/* inhrel */
		datum[1] = ObjectIdGetDatum(entryOid);	/* inhparent */
		datum[2] = Int16GetDatum(seqNumber);	/* inhseqno */
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		nullarr[0] = ' ';
		nullarr[1] = ' ';
		nullarr[2] = ' ';
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		tuple = heap_formtuple(desc, datum, nullarr);
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		simple_heap_insert(relation, tuple);
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		CatalogUpdateIndexes(relation, tuple);
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		heap_freetuple(tuple);
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		/*
		 * Store a dependency too
		 */
		parentobject.classId = RelOid_pg_class;
		parentobject.objectId = entryOid;
		parentobject.objectSubId = 0;
		childobject.classId = RelOid_pg_class;
		childobject.objectId = relationId;
		childobject.objectSubId = 0;

		recordDependencyOn(&childobject, &parentobject, DEPENDENCY_NORMAL);

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		seqNumber += 1;
	}
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	heap_close(relation, RowExclusiveLock);
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	/* ----------------
	 * Expand supers list to include indirect ancestors as well.
	 *
	 * Algorithm:
	 *	0. begin with list of direct superclasses.
	 *	1. append after each relationId, its superclasses, recursively.
	 *	2. remove all but last of duplicates.
	 * ----------------
	 */

	/*
	 * 1. append after each relationId, its superclasses, recursively.
	 */
	foreach(entry, supers)
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	{
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		HeapTuple	tuple;
		Oid			id;
		int16		number;
		List	   *next;
		List	   *current;
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		id = (Oid) lfirsti(entry);
		current = entry;
		next = lnext(entry);
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		for (number = 1;; number += 1)
		{
			tuple = SearchSysCache(INHRELID,
								   ObjectIdGetDatum(id),
								   Int16GetDatum(number),
								   0, 0);
			if (!HeapTupleIsValid(tuple))
				break;
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			lnext(current) = lconsi(((Form_pg_inherits)
									 GETSTRUCT(tuple))->inhparent,
									NIL);

			ReleaseSysCache(tuple);

			current = lnext(current);
		}
		lnext(current) = next;
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	}

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	/*
	 * 2. remove all but last of duplicates.
	 */
	foreach(entry, supers)
	{
		Oid			thisone;
		bool		found;
		List	   *rest;
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again:
		thisone = lfirsti(entry);
		found = false;
		foreach(rest, lnext(entry))
		{
			if (thisone == lfirsti(rest))
			{
				found = true;
				break;
			}
		}
		if (found)
		{
			/*
			 * found a later duplicate, so remove this entry.
			 */
			lfirsti(entry) = lfirsti(lnext(entry));
			lnext(entry) = lnext(lnext(entry));
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			goto again;
		}
	}
}
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/*
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 * Look for an existing schema entry with the given name.
 *
 * Returns the index (starting with 1) if attribute already exists in schema,
 * 0 if it doesn't.
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 */
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static int
findAttrByName(const char *attributeName, List *schema)
946
{
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	List	   *s;
	int			i = 0;

	foreach(s, schema)
	{
		ColumnDef  *def = lfirst(s);

		++i;
		if (strcmp(attributeName, def->colname) == 0)
			return i;
	}
	return 0;
959
}
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/*
 * Update a relation's pg_class.relhassubclass entry to the given value
 */
static void
setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
{
	Relation	relationRelation;
	HeapTuple	tuple;

	/*
	 * Fetch a modifiable copy of the tuple, modify it, update pg_class.
	 */
	relationRelation = heap_openr(RelationRelationName, RowExclusiveLock);
	tuple = SearchSysCacheCopy(RELOID,
							   ObjectIdGetDatum(relationId),
							   0, 0, 0);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "setRelhassubclassInRelation: cache lookup failed for relation %u", relationId);

	((Form_pg_class) GETSTRUCT(tuple))->relhassubclass = relhassubclass;
	simple_heap_update(relationRelation, &tuple->t_self, tuple);

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	/* keep the catalog indexes up to date */
	CatalogUpdateIndexes(relationRelation, tuple);
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	heap_freetuple(tuple);
	heap_close(relationRelation, RowExclusiveLock);
}
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991
/*
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 *		renameatt		- changes the name of a attribute in a relation
 *
 *		Attname attribute is changed in attribute catalog.
 *		No record of the previous attname is kept (correct?).
 *
 *		get proper relrelation from relation catalog (if not arg)
 *		scan attribute catalog
 *				for name conflict (within rel)
 *				for original attribute (if not arg)
 *		modify attname in attribute tuple
 *		insert modified attribute in attribute catalog
 *		delete original attribute from attribute catalog
1004
 */
1005
void
1006 1007 1008 1009
renameatt(Oid relid,
		  const char *oldattname,
		  const char *newattname,
		  bool recurse)
1010
{
1011 1012 1013 1014 1015
	Relation	targetrelation;
	Relation	attrelation;
	HeapTuple	atttup;
	List	   *indexoidlist;
	List	   *indexoidscan;
1016

1017 1018 1019 1020
	/*
	 * Grab an exclusive lock on the target table, which we will NOT
	 * release until end of transaction.
	 */
1021
	targetrelation = heap_open(relid, AccessExclusiveLock);
1022

1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033
	/*
	 * permissions checking.  this would normally be done in utility.c,
	 * but this particular routine is recursive.
	 *
	 * normally, only the owner of a class can change its schema.
	 */
	if (!allowSystemTableMods 
		&& IsSystemRelation(targetrelation))
		elog(ERROR, "renameatt: class \"%s\" is a system catalog",
			 RelationGetRelationName(targetrelation));
	if (!pg_class_ownercheck(relid, GetUserId()))
1034 1035
		aclcheck_error(ACLCHECK_NOT_OWNER,
					   RelationGetRelationName(targetrelation));
1036

1037 1038 1039 1040 1041 1042 1043 1044 1045 1046
	/*
	 * if the 'recurse' flag is set then we are supposed to rename this
	 * attribute in all classes that inherit from 'relname' (as well as in
	 * 'relname').
	 *
	 * any permissions or problems with duplicate attributes will cause the
	 * whole transaction to abort, which is what we want -- all or
	 * nothing.
	 */
	if (recurse)
1047
	{
1048 1049 1050 1051
		List	   *child,
				   *children;

		/* this routine is actually in the planner */
1052
		children = find_all_inheritors(relid);
1053 1054 1055

		/*
		 * find_all_inheritors does the recursive search of the
1056 1057
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
1058 1059 1060 1061 1062
		 */
		foreach(child, children)
		{
			Oid			childrelid = lfirsti(child);

1063
			if (childrelid == relid)
1064
				continue;
1065 1066
			/* note we need not recurse again! */
			renameatt(childrelid, oldattname, newattname, false);
1067 1068 1069
		}
	}

1070
	attrelation = heap_openr(AttributeRelationName, RowExclusiveLock);
1071

1072
	atttup = SearchSysCacheCopyAttName(relid, oldattname);
1073
	if (!HeapTupleIsValid(atttup))
1074 1075
		elog(ERROR, "renameatt: attribute \"%s\" does not exist",
			 oldattname);
1076

1077
	if (((Form_pg_attribute) GETSTRUCT(atttup))->attnum < 0)
1078 1079
		elog(ERROR, "renameatt: system attribute \"%s\" may not be renamed",
			 oldattname);
1080

1081
	/* should not already exist */
1082
	/* this test is deliberately not attisdropped-aware */
1083 1084 1085 1086 1087
	if (SearchSysCacheExists(ATTNAME,
							 ObjectIdGetDatum(relid),
							 PointerGetDatum(newattname),
							 0, 0))
		elog(ERROR, "renameatt: attribute \"%s\" exists", newattname);
1088

1089 1090
	namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
			   newattname);
1091

1092
	simple_heap_update(attrelation, &atttup->t_self, atttup);
1093

1094 1095
	/* keep system catalog indexes current */
	CatalogUpdateIndexes(attrelation, atttup);
1096

1097
	heap_freetuple(atttup);
1098

1099 1100 1101 1102 1103
	/*
	 * Update column names of indexes that refer to the column being
	 * renamed.
	 */
	indexoidlist = RelationGetIndexList(targetrelation);
1104

1105 1106 1107 1108
	foreach(indexoidscan, indexoidlist)
	{
		Oid			indexoid = lfirsti(indexoidscan);
		HeapTuple	indextup;
1109

1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124
		/*
		 * First check to see if index is a functional index. If so, its
		 * column name is a function name and shouldn't be renamed here.
		 */
		indextup = SearchSysCache(INDEXRELID,
								  ObjectIdGetDatum(indexoid),
								  0, 0, 0);
		if (!HeapTupleIsValid(indextup))
			elog(ERROR, "renameatt: can't find index id %u", indexoid);
		if (OidIsValid(((Form_pg_index) GETSTRUCT(indextup))->indproc))
		{
			ReleaseSysCache(indextup);
			continue;
		}
		ReleaseSysCache(indextup);
1125

1126 1127 1128 1129
		/*
		 * Okay, look to see if any column name of the index matches the
		 * old attribute name.
		 */
1130
		atttup = SearchSysCacheCopyAttName(indexoid, oldattname);
1131 1132
		if (!HeapTupleIsValid(atttup))
			continue;			/* Nope, so ignore it */
1133

1134 1135 1136 1137 1138
		/*
		 * Update the (copied) attribute tuple.
		 */
		namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
				   newattname);
1139

1140
		simple_heap_update(attrelation, &atttup->t_self, atttup);
1141

1142 1143
		/* keep system catalog indexes current */
		CatalogUpdateIndexes(attrelation, atttup);
1144

1145 1146
		heap_freetuple(atttup);
	}
1147

1148
	freeList(indexoidlist);
1149

1150
	heap_close(attrelation, RowExclusiveLock);
1151

1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164
	/*
	 * Update att name in any RI triggers associated with the relation.
	 */
	if (targetrelation->rd_rel->reltriggers > 0)
	{
		/* update tgargs column reference where att is primary key */
		update_ri_trigger_args(RelationGetRelid(targetrelation),
							   oldattname, newattname,
							   false, false);
		/* update tgargs column reference where att is foreign key */
		update_ri_trigger_args(RelationGetRelid(targetrelation),
							   oldattname, newattname,
							   true, false);
1165 1166
	}

1167
	heap_close(targetrelation, NoLock); /* close rel but keep lock! */
1168 1169
}

1170
/*
1171 1172 1173 1174 1175 1176 1177
 *		renamerel		- change the name of a relation
 *
 *		XXX - When renaming sequences, we don't bother to modify the
 *			  sequence name that is stored within the sequence itself
 *			  (this would cause problems with MVCC). In the future,
 *			  the sequence name should probably be removed from the
 *			  sequence, AFAIK there's no need for it to be there.
1178 1179
 */
void
1180
renamerel(Oid relid, const char *newrelname)
1181
{
1182 1183 1184 1185 1186 1187 1188
	Relation	targetrelation;
	Relation	relrelation;	/* for RELATION relation */
	HeapTuple	reltup;
	Oid			namespaceId;
	char	   *oldrelname;
	char		relkind;
	bool		relhastriggers;
1189

1190
	/*
1191 1192
	 * Grab an exclusive lock on the target table or index, which we will
	 * NOT release until end of transaction.
1193
	 */
1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206
	targetrelation = relation_open(relid, AccessExclusiveLock);

	oldrelname = pstrdup(RelationGetRelationName(targetrelation));
	namespaceId = RelationGetNamespace(targetrelation);

	/* Validity checks */
	if (!allowSystemTableMods &&
		IsSystemRelation(targetrelation))
		elog(ERROR, "renamerel: system relation \"%s\" may not be renamed",
			 oldrelname);

	relkind = targetrelation->rd_rel->relkind;
	relhastriggers = (targetrelation->rd_rel->reltriggers > 0);
1207 1208

	/*
1209 1210
	 * Find relation's pg_class tuple, and make sure newrelname isn't in
	 * use.
1211
	 */
1212
	relrelation = heap_openr(RelationRelationName, RowExclusiveLock);
1213

1214 1215 1216 1217 1218 1219
	reltup = SearchSysCacheCopy(RELOID,
								PointerGetDatum(relid),
								0, 0, 0);
	if (!HeapTupleIsValid(reltup))
		elog(ERROR, "renamerel: relation \"%s\" does not exist",
			 oldrelname);
1220

1221 1222
	if (get_relname_relid(newrelname, namespaceId) != InvalidOid)
		elog(ERROR, "renamerel: relation \"%s\" exists", newrelname);
1223

1224
	/*
1225 1226
	 * Update pg_class tuple with new relname.	(Scribbling on reltup is
	 * OK because it's a copy...)
1227
	 */
1228
	namestrcpy(&(((Form_pg_class) GETSTRUCT(reltup))->relname), newrelname);
1229

1230 1231
	simple_heap_update(relrelation, &reltup->t_self, reltup);

1232 1233
	/* keep the system catalog indexes current */
	CatalogUpdateIndexes(relrelation, reltup);
1234 1235 1236

	heap_close(relrelation, NoLock);
	heap_freetuple(reltup);
1237 1238

	/*
1239
	 * Also rename the associated type, if any.
1240
	 */
1241 1242
	if (relkind != RELKIND_INDEX)
		TypeRename(oldrelname, namespaceId, newrelname);
1243

1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259
	/*
	 * Update rel name in any RI triggers associated with the relation.
	 */
	if (relhastriggers)
	{
		/* update tgargs where relname is primary key */
		update_ri_trigger_args(relid,
							   oldrelname,
							   newrelname,
							   false, true);
		/* update tgargs where relname is foreign key */
		update_ri_trigger_args(relid,
							   oldrelname,
							   newrelname,
							   true, true);
	}
1260 1261

	/*
1262
	 * Close rel, but keep exclusive lock!
1263
	 */
1264 1265
	relation_close(targetrelation, NoLock);
}
1266 1267


1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297
/*
 * Given a trigger function OID, determine whether it is an RI trigger,
 * and if so whether it is attached to PK or FK relation.
 *
 * XXX this probably doesn't belong here; should be exported by
 * ri_triggers.c
 */
static int
ri_trigger_type(Oid tgfoid)
{
	switch (tgfoid)
	{
		case F_RI_FKEY_CASCADE_DEL:
		case F_RI_FKEY_CASCADE_UPD:
		case F_RI_FKEY_RESTRICT_DEL:
		case F_RI_FKEY_RESTRICT_UPD:
		case F_RI_FKEY_SETNULL_DEL:
		case F_RI_FKEY_SETNULL_UPD:
		case F_RI_FKEY_SETDEFAULT_DEL:
		case F_RI_FKEY_SETDEFAULT_UPD:
		case F_RI_FKEY_NOACTION_DEL:
		case F_RI_FKEY_NOACTION_UPD:
			return RI_TRIGGER_PK;

		case F_RI_FKEY_CHECK_INS:
		case F_RI_FKEY_CHECK_UPD:
			return RI_TRIGGER_FK;
	}

	return RI_TRIGGER_NONE;
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}

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/*
 * Scan pg_trigger for RI triggers that are on the specified relation
 * (if fk_scan is false) or have it as the tgconstrrel (if fk_scan
 * is true).  Update RI trigger args fields matching oldname to contain
 * newname instead.  If update_relname is true, examine the relname
 * fields; otherwise examine the attname fields.
 */
static void
update_ri_trigger_args(Oid relid,
					   const char *oldname,
					   const char *newname,
					   bool fk_scan,
					   bool update_relname)
{
	Relation	tgrel;
	ScanKeyData skey[1];
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	SysScanDesc	trigscan;
	HeapTuple	tuple;
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	Datum		values[Natts_pg_trigger];
	char		nulls[Natts_pg_trigger];
	char		replaces[Natts_pg_trigger];

	tgrel = heap_openr(TriggerRelationName, RowExclusiveLock);
	if (fk_scan)
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	{
		ScanKeyEntryInitialize(&skey[0], 0x0,
							   Anum_pg_trigger_tgconstrrelid,
							   F_OIDEQ,
							   ObjectIdGetDatum(relid));
		trigscan = systable_beginscan(tgrel, TriggerConstrRelidIndex,
									  true, SnapshotNow,
									  1, skey);
	}
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	else
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	{
		ScanKeyEntryInitialize(&skey[0], 0x0,
							   Anum_pg_trigger_tgrelid,
							   F_OIDEQ,
							   ObjectIdGetDatum(relid));
		trigscan = systable_beginscan(tgrel, TriggerRelidNameIndex,
									  true, SnapshotNow,
									  1, skey);
	}
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	while ((tuple = systable_getnext(trigscan)) != NULL)
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	{
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		Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
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		bytea	   *val;
		bytea	   *newtgargs;
		bool		isnull;
		int			tg_type;
		bool		examine_pk;
		bool		changed;
		int			tgnargs;
		int			i;
		int			newlen;
		const char *arga[RI_MAX_ARGUMENTS];
		const char *argp;

		tg_type = ri_trigger_type(pg_trigger->tgfoid);
		if (tg_type == RI_TRIGGER_NONE)
		{
			/* Not an RI trigger, forget it */
			continue;
		}

		/*
		 * It is an RI trigger, so parse the tgargs bytea.
		 *
		 * NB: we assume the field will never be compressed or moved out of
		 * line; so does trigger.c ...
		 */
		tgnargs = pg_trigger->tgnargs;
		val = (bytea *) fastgetattr(tuple,
									Anum_pg_trigger_tgargs,
									tgrel->rd_att, &isnull);
		if (isnull || tgnargs < RI_FIRST_ATTNAME_ARGNO ||
			tgnargs > RI_MAX_ARGUMENTS)
		{
			/* This probably shouldn't happen, but ignore busted triggers */
			continue;
		}
		argp = (const char *) VARDATA(val);
		for (i = 0; i < tgnargs; i++)
		{
			arga[i] = argp;
			argp += strlen(argp) + 1;
		}
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		/*
		 * Figure out which item(s) to look at.  If the trigger is
		 * primary-key type and attached to my rel, I should look at the
		 * PK fields; if it is foreign-key type and attached to my rel, I
		 * should look at the FK fields.  But the opposite rule holds when
		 * examining triggers found by tgconstrrel search.
		 */
		examine_pk = (tg_type == RI_TRIGGER_PK) == (!fk_scan);
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		changed = false;
		if (update_relname)
		{
			/* Change the relname if needed */
			i = examine_pk ? RI_PK_RELNAME_ARGNO : RI_FK_RELNAME_ARGNO;
			if (strcmp(arga[i], oldname) == 0)
			{
				arga[i] = newname;
				changed = true;
			}
		}
		else
		{
			/* Change attname(s) if needed */
			i = examine_pk ? RI_FIRST_ATTNAME_ARGNO + RI_KEYPAIR_PK_IDX :
				RI_FIRST_ATTNAME_ARGNO + RI_KEYPAIR_FK_IDX;
			for (; i < tgnargs; i += 2)
			{
				if (strcmp(arga[i], oldname) == 0)
				{
					arga[i] = newname;
					changed = true;
				}
			}
		}
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		if (!changed)
		{
			/* Don't need to update this tuple */
			continue;
		}
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		/*
		 * Construct modified tgargs bytea.
		 */
		newlen = VARHDRSZ;
		for (i = 0; i < tgnargs; i++)
			newlen += strlen(arga[i]) + 1;
		newtgargs = (bytea *) palloc(newlen);
		VARATT_SIZEP(newtgargs) = newlen;
		newlen = VARHDRSZ;
		for (i = 0; i < tgnargs; i++)
		{
			strcpy(((char *) newtgargs) + newlen, arga[i]);
			newlen += strlen(arga[i]) + 1;
		}
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		/*
		 * Build modified tuple.
		 */
		for (i = 0; i < Natts_pg_trigger; i++)
		{
			values[i] = (Datum) 0;
			replaces[i] = ' ';
			nulls[i] = ' ';
		}
		values[Anum_pg_trigger_tgargs - 1] = PointerGetDatum(newtgargs);
		replaces[Anum_pg_trigger_tgargs - 1] = 'r';
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		tuple = heap_modifytuple(tuple, tgrel, values, nulls, replaces);
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		/*
		 * Update pg_trigger and its indexes
		 */
		simple_heap_update(tgrel, &tuple->t_self, tuple);
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		CatalogUpdateIndexes(tgrel, tuple);
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		/* free up our scratch memory */
		pfree(newtgargs);
		heap_freetuple(tuple);
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	}
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	systable_endscan(trigscan);
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	heap_close(tgrel, RowExclusiveLock);
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	/*
	 * Increment cmd counter to make updates visible; this is needed in
	 * case the same tuple has to be updated again by next pass (can
	 * happen in case of a self-referential FK relationship).
	 */
	CommandCounterIncrement();
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}
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/* ----------------
 *		AlterTableAddColumn
 *		(formerly known as PerformAddAttribute)
 *
 *		adds an additional attribute to a relation
 *
 *		Adds attribute field(s) to a relation.	Each new attribute
 *		is given attnums in sequential order and is added to the
 *		ATTRIBUTE relation.  If the AMI fails, defunct tuples will
 *		remain in the ATTRIBUTE relation for later vacuuming.
 *		Later, there may be some reserved attribute names???
 *
 *		(If needed, can instead use elog to handle exceptions.)
 *
 *		Note:
 *				Initial idea of ordering the tuple attributes so that all
 *		the variable length domains occured last was scratched.  Doing
 *		so would not speed access too much (in general) and would create
 *		many complications in formtuple, heap_getattr, and addattribute.
 *
 *		scan attribute catalog for name conflict (within rel)
 *		scan type catalog for absence of data type (if not arg)
 *		create attnum magically???
 *		create attribute tuple
 *		insert attribute in attribute catalog
 *		modify reldesc
 *		create new relation tuple
 *		insert new relation in relation catalog
 *		delete original relation from relation catalog
 * ----------------
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 */
void
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AlterTableAddColumn(Oid myrelid,
					bool inherits,
					ColumnDef *colDef)
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{
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	Relation	rel,
				pgclass,
				attrdesc;
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	HeapTuple	reltup;
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	HeapTuple	newreltup;
	HeapTuple	attributeTuple;
	Form_pg_attribute attribute;
	FormData_pg_attribute attributeD;
	int			i;
	int			minattnum,
				maxatts;
	HeapTuple	typeTuple;
	Form_pg_type tform;
	int			attndims;
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	ObjectAddress	myself,
					referenced;
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	/*
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	 * Grab an exclusive lock on the target table, which we will NOT
	 * release until end of transaction.
	 */
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	rel = heap_open(myrelid, AccessExclusiveLock);
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	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
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			 RelationGetRelationName(rel));
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	/*
	 * permissions checking.  this would normally be done in utility.c,
	 * but this particular routine is recursive.
	 *
	 * normally, only the owner of a class can change its schema.
	 */
	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
			 RelationGetRelationName(rel));
	if (!pg_class_ownercheck(myrelid, GetUserId()))
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		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
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	/*
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	 * Recurse to add the column to child classes, if requested.
	 *
	 * any permissions or problems with duplicate attributes will cause the
	 * whole transaction to abort, which is what we want -- all or
	 * nothing.
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	 */
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	if (inherits)
	{
		List	   *child,
				   *children;

		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);

		/*
		 * find_all_inheritors does the recursive search of the
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
		 */
		foreach(child, children)
		{
			Oid			childrelid = lfirsti(child);

			if (childrelid == myrelid)
				continue;

			AlterTableAddColumn(childrelid, false, colDef);
		}
	}

	/*
	 * OK, get on with it...
	 *
	 * Implementation restrictions: because we don't touch the table rows,
	 * the new column values will initially appear to be NULLs.  (This
	 * happens because the heap tuple access routines always check for
	 * attnum > # of attributes in tuple, and return NULL if so.)
	 * Therefore we can't support a DEFAULT value in SQL92-compliant
	 * fashion, and we also can't allow a NOT NULL constraint.
	 *
	 * We do allow CHECK constraints, even though these theoretically could
	 * fail for NULL rows (eg, CHECK (newcol IS NOT NULL)).
	 */
	if (colDef->raw_default || colDef->cooked_default)
		elog(ERROR, "Adding columns with defaults is not implemented."
			 "\n\tAdd the column, then use ALTER TABLE SET DEFAULT.");

	if (colDef->is_not_null)
		elog(ERROR, "Adding NOT NULL columns is not implemented."
			 "\n\tAdd the column, then use ALTER TABLE ... SET NOT NULL.");

	pgclass = heap_openr(RelationRelationName, RowExclusiveLock);
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	reltup = SearchSysCache(RELOID,
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							ObjectIdGetDatum(myrelid),
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							0, 0, 0);
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	if (!HeapTupleIsValid(reltup))
		elog(ERROR, "ALTER TABLE: relation \"%s\" not found",
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			 RelationGetRelationName(rel));
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	/*
	 * this test is deliberately not attisdropped-aware, since if one tries
	 * to add a column matching a dropped column name, it's gonna fail anyway.
	 */
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	if (SearchSysCacheExists(ATTNAME,
							 ObjectIdGetDatum(myrelid),
							 PointerGetDatum(colDef->colname),
							 0, 0))
		elog(ERROR, "ALTER TABLE: column name \"%s\" already exists in table \"%s\"",
			 colDef->colname, RelationGetRelationName(rel));
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	minattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts;
	maxatts = minattnum + 1;
	if (maxatts > MaxHeapAttributeNumber)
		elog(ERROR, "ALTER TABLE: relations limited to %d columns",
			 MaxHeapAttributeNumber);
	i = minattnum + 1;
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	attrdesc = heap_openr(AttributeRelationName, RowExclusiveLock);
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	if (colDef->typename->arrayBounds)
		attndims = length(colDef->typename->arrayBounds);
	else
		attndims = 0;
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	typeTuple = typenameType(colDef->typename);
	tform = (Form_pg_type) GETSTRUCT(typeTuple);
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	attributeTuple = heap_addheader(Natts_pg_attribute,
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	                                false,
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									ATTRIBUTE_TUPLE_SIZE,
									(void *) &attributeD);
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	attribute = (Form_pg_attribute) GETSTRUCT(attributeTuple);
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	attribute->attrelid = myrelid;
	namestrcpy(&(attribute->attname), colDef->colname);
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	attribute->atttypid = HeapTupleGetOid(typeTuple);
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	attribute->attstattarget = -1;
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	attribute->attlen = tform->typlen;
	attribute->attcacheoff = -1;
	attribute->atttypmod = colDef->typename->typmod;
	attribute->attnum = i;
	attribute->attbyval = tform->typbyval;
	attribute->attndims = attndims;
	attribute->attisset = (bool) (tform->typtype == 'c');
	attribute->attstorage = tform->typstorage;
	attribute->attalign = tform->typalign;
	attribute->attnotnull = colDef->is_not_null;
	attribute->atthasdef = (colDef->raw_default != NULL ||
							colDef->cooked_default != NULL);
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	attribute->attisdropped = false;
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	ReleaseSysCache(typeTuple);
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	AssertTupleDescHasNoOid(attrdesc->rd_att);
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	simple_heap_insert(attrdesc, attributeTuple);
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	/* Update indexes on pg_attribute */
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	CatalogUpdateIndexes(attrdesc, attributeTuple);
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	heap_close(attrdesc, RowExclusiveLock);
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	/*
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	 * Update number of attributes in pg_class tuple
1686
	 */
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	newreltup = heap_copytuple(reltup);
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1689
	((Form_pg_class) GETSTRUCT(newreltup))->relnatts = maxatts;
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	AssertTupleDescHasOid(pgclass->rd_att);
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	simple_heap_update(pgclass, &newreltup->t_self, newreltup);
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	/* keep catalog indexes current */
	CatalogUpdateIndexes(pgclass, newreltup);
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	heap_freetuple(newreltup);
	ReleaseSysCache(reltup);
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	heap_close(pgclass, NoLock);

	heap_close(rel, NoLock);	/* close rel but keep lock! */
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	/*
	 * Add datatype dependency for the new column.
	 */
	myself.classId = RelOid_pg_class;
	myself.objectId = myrelid;
	myself.objectSubId = i;
	referenced.classId = RelOid_pg_type;
	referenced.objectId = attribute->atttypid;
	referenced.objectSubId = 0;
	recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

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	/*
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	 * Make our catalog updates visible for subsequent steps.
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	 */
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	CommandCounterIncrement();
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	/*
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	 * Add any CHECK constraints attached to the new column.
	 *
	 * To do this we must re-open the rel so that its new attr list gets
	 * loaded into the relcache.
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	 */
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	if (colDef->constraints != NIL)
	{
		rel = heap_open(myrelid, AccessExclusiveLock);
		AddRelationRawConstraints(rel, NIL, colDef->constraints);
		heap_close(rel, NoLock);
	}
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	/*
	 * Automatically create the secondary relation for TOAST if it
	 * formerly had no such but now has toastable attributes.
	 */
	AlterTableCreateToastTable(myrelid, true);
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}

1739
/*
1740
 * ALTER TABLE ALTER COLUMN DROP NOT NULL
1741
 */
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void
AlterTableAlterColumnDropNotNull(Oid myrelid,
								 bool inh, const char *colName)
1745
{
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	Relation	rel;
	HeapTuple	tuple;
	AttrNumber	attnum;
	Relation	attr_rel;
	List	   	*indexoidlist;
	List	   	*indexoidscan;
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	rel = heap_open(myrelid, AccessExclusiveLock);
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	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
			 RelationGetRelationName(rel));

	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
			 RelationGetRelationName(rel));

	if (!pg_class_ownercheck(myrelid, GetUserId()))
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		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
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	/*
	 * Propagate to children if desired
	 */
	if (inh)
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	{
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		List	   *child,
				   *children;

		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);

		/*
		 * find_all_inheritors does the recursive search of the
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
		 */
		foreach(child, children)
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		{
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			Oid			childrelid = lfirsti(child);
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			if (childrelid == myrelid)
				continue;
			AlterTableAlterColumnDropNotNull(childrelid,
											 false, colName);
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		}
	}
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	/* -= now do the thing on this relation =- */
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	/*
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	 * get the number of the attribute
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	 */
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	attnum = get_attnum(myrelid, colName);
	if (attnum == InvalidAttrNumber)
		elog(ERROR, "Relation \"%s\" has no column \"%s\"",
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			 RelationGetRelationName(rel), colName);
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	/* Prevent them from altering a system attribute */
	if (attnum < 0)
		elog(ERROR, "ALTER TABLE: Cannot alter system attribute \"%s\"",
			 colName);
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	/*
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	 * Check that the attribute is not in a primary key
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	 */
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1813
	/* Loop over all indexes on the relation */
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	indexoidlist = RelationGetIndexList(rel);
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	foreach(indexoidscan, indexoidlist)
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	{
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		Oid		indexoid = lfirsti(indexoidscan);
		HeapTuple	indexTuple;
		Form_pg_index 	indexStruct;
		int		i;
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		indexTuple = SearchSysCache(INDEXRELID,
									ObjectIdGetDatum(indexoid),
									0, 0, 0);
		if (!HeapTupleIsValid(indexTuple))
			elog(ERROR, "ALTER TABLE: Index %u not found",
				 indexoid);
		indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
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		/* If the index is not a primary key, skip the check */
		if (indexStruct->indisprimary)
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		{
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			/*
			 * Loop over each attribute in the primary key and
			 * see if it matches the to-be-altered attribute
			 */
			for (i = 0; i < INDEX_MAX_KEYS &&
					 indexStruct->indkey[i] != InvalidAttrNumber; i++)
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			{
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				if (indexStruct->indkey[i] == attnum)
					elog(ERROR, "ALTER TABLE: Attribute \"%s\" is in a primary key", colName);
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			}
		}

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		ReleaseSysCache(indexTuple);
	}
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	freeList(indexoidlist);
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	/*
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	 * Okay, actually perform the catalog change
1853
	 */
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	attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);
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	tuple = SearchSysCacheCopyAttName(myrelid, colName);
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	if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
		elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
			 RelationGetRelationName(rel), colName);
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1861
	((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = FALSE;
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1863
	simple_heap_update(attr_rel, &tuple->t_self, tuple);
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	/* keep the system catalog indexes current */
	CatalogUpdateIndexes(attr_rel, tuple);
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	heap_close(attr_rel, RowExclusiveLock);
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	heap_close(rel, NoLock);
}
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/*
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 * ALTER TABLE ALTER COLUMN SET NOT NULL
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 */
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void
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AlterTableAlterColumnSetNotNull(Oid myrelid,
								bool inh, const char *colName)
1879
{
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	Relation	rel;
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	HeapTuple	tuple;
	AttrNumber	attnum;
	Relation	attr_rel;
	HeapScanDesc 	scan;
	TupleDesc	tupdesc;
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	rel = heap_open(myrelid, AccessExclusiveLock);
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	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
1891
			 RelationGetRelationName(rel));
1892

1893 1894 1895
	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
1896
			 RelationGetRelationName(rel));
1897

1898
	if (!pg_class_ownercheck(myrelid, GetUserId()))
1899
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
1900 1901

	/*
1902
	 * Propagate to children if desired
1903
	 */
1904
	if (inh)
1905
	{
1906 1907
		List	   *child,
				   *children;
1908

1909 1910
		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);
1911

1912 1913 1914 1915 1916 1917
		/*
		 * find_all_inheritors does the recursive search of the
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
		 */
		foreach(child, children)
1918
		{
1919
			Oid			childrelid = lfirsti(child);
1920

1921 1922 1923 1924 1925
			if (childrelid == myrelid)
				continue;
			AlterTableAlterColumnSetNotNull(childrelid,
											false, colName);
		}
1926 1927
	}

1928 1929
	/* -= now do the thing on this relation =- */

1930
	/*
1931
	 * get the number of the attribute
1932
	 */
1933 1934 1935
	attnum = get_attnum(myrelid, colName);
	if (attnum == InvalidAttrNumber)
		elog(ERROR, "Relation \"%s\" has no column \"%s\"",
1936
			 RelationGetRelationName(rel), colName);
1937

1938 1939 1940 1941
	/* Prevent them from altering a system attribute */
	if (attnum < 0)
		elog(ERROR, "ALTER TABLE: Cannot alter system attribute \"%s\"",
			 colName);
1942

1943
	/*
1944 1945
	 * Perform a scan to ensure that there are no NULL
	 * values already in the relation
1946
	 */
1947
	tupdesc = RelationGetDescr(rel);
1948

1949
	scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
1950

1951
	while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
1952 1953 1954
	{
		Datum 		d;
		bool		isnull;
1955

1956
		d = heap_getattr(tuple, attnum, tupdesc, &isnull);
1957

1958 1959 1960 1961
		if (isnull)
			elog(ERROR, "ALTER TABLE: Attribute \"%s\" contains NULL values",
				 colName);
	}
1962

1963
	heap_endscan(scan);
1964

1965 1966 1967 1968
	/*
	 * Okay, actually perform the catalog change
	 */
	attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);
1969

1970
	tuple = SearchSysCacheCopyAttName(myrelid, colName);
1971 1972 1973
	if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
		elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
			 RelationGetRelationName(rel), colName);
1974

1975
	((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = TRUE;
1976

1977
	simple_heap_update(attr_rel, &tuple->t_self, tuple);
1978

1979 1980
	/* keep the system catalog indexes current */
	CatalogUpdateIndexes(attr_rel, tuple);
1981

1982
	heap_close(attr_rel, RowExclusiveLock);
1983

1984 1985
	heap_close(rel, NoLock);
}
1986 1987


1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
/*
 * ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
 */
void
AlterTableAlterColumnDefault(Oid myrelid,
							 bool inh, const char *colName,
							 Node *newDefault)
{
	Relation	rel;
	AttrNumber	attnum;
1998

1999
	rel = heap_open(myrelid, AccessExclusiveLock);
2000

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
	/*
	 * We allow defaults on views so that INSERT into a view can have
	 * default-ish behavior.  This works because the rewriter substitutes
	 * default values into INSERTs before it expands rules.
	 */
	if (rel->rd_rel->relkind != RELKIND_RELATION &&
		rel->rd_rel->relkind != RELKIND_VIEW)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table or view",
			 RelationGetRelationName(rel));

	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
			 RelationGetRelationName(rel));
2015

2016
	if (!pg_class_ownercheck(myrelid, GetUserId()))
2017
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
2018 2019

	/*
2020
	 * Propagate to children if desired
2021
	 */
2022
	if (inh)
2023
	{
2024 2025
		List	   *child,
				   *children;
2026

2027 2028
		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);
2029

2030 2031 2032 2033 2034 2035 2036 2037
		/*
		 * find_all_inheritors does the recursive search of the
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
		 */
		foreach(child, children)
		{
			Oid			childrelid = lfirsti(child);
2038

2039 2040 2041 2042 2043
			if (childrelid == myrelid)
				continue;
			AlterTableAlterColumnDefault(childrelid,
										 false, colName, newDefault);
		}
2044 2045
	}

2046 2047
	/* -= now do the thing on this relation =- */

2048
	/*
2049
	 * get the number of the attribute
2050
	 */
2051 2052 2053
	attnum = get_attnum(myrelid, colName);
	if (attnum == InvalidAttrNumber)
		elog(ERROR, "Relation \"%s\" has no column \"%s\"",
2054 2055
			 RelationGetRelationName(rel), colName);

2056 2057 2058 2059
	/* Prevent them from altering a system attribute */
	if (attnum < 0)
		elog(ERROR, "ALTER TABLE: Cannot alter system attribute \"%s\"",
			 colName);
2060

2061 2062 2063 2064 2065 2066 2067
	/*
	 * Remove any old default for the column.  We use RESTRICT here for
	 * safety, but at present we do not expect anything to depend on the
	 * default.
	 */
	RemoveAttrDefault(myrelid, attnum, DROP_RESTRICT, false);

2068
	if (newDefault)
2069
	{
2070 2071
		/* SET DEFAULT */
		RawColumnDefault *rawEnt;
2072

2073 2074 2075
		rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
		rawEnt->attnum = attnum;
		rawEnt->raw_default = newDefault;
2076

2077 2078 2079 2080 2081 2082
		/*
		 * This function is intended for CREATE TABLE, so it processes a
		 * _list_ of defaults, but we just do one.
		 */
		AddRelationRawConstraints(rel, makeList1(rawEnt), NIL);
	}
2083

2084
	heap_close(rel, NoLock);
2085 2086
}

2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102
/*
 * ALTER TABLE ALTER COLUMN SET STATISTICS / STORAGE
 */
void
AlterTableAlterColumnFlags(Oid myrelid,
						   bool inh, const char *colName,
						   Node *flagValue, const char *flagType)
{
	Relation	rel;
	int			newtarget = 1;
	char        newstorage = 'p';
	Relation	attrelation;
	HeapTuple	tuple;
	Form_pg_attribute attrtuple;

	rel = heap_open(myrelid, AccessExclusiveLock);
2103

2104 2105 2106
	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
			 RelationGetRelationName(rel));
2107

2108 2109 2110 2111 2112 2113
	/*
	 * we allow statistics case for system tables
	 */
	if (*flagType != 'S' && !allowSystemTableMods && IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
			 RelationGetRelationName(rel));
2114

2115
	if (!pg_class_ownercheck(myrelid, GetUserId()))
2116
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
2117

2118 2119 2120 2121 2122 2123 2124 2125
	/*
	 * Check the supplied parameters before anything else
	 */
	if (*flagType == 'S')
	{
		/* STATISTICS */
		Assert(IsA(flagValue, Integer));
		newtarget = intVal(flagValue);
2126

2127
		/*
2128
		 * Limit target to a sane range
2129
		 */
2130 2131 2132 2133 2134
		if (newtarget < -1)
		{
			elog(ERROR, "ALTER TABLE: statistics target %d is too low",
				 newtarget);
		}
2135
		else if (newtarget > 1000)
2136 2137
		{
			elog(WARNING, "ALTER TABLE: lowering statistics target to 1000");
2138
			newtarget = 1000;
2139
		}
2140
	}
2141 2142 2143 2144
	else if (*flagType == 'M')
	{
		/* STORAGE */
		char        *storagemode;
2145

2146 2147
		Assert(IsA(flagValue, String));
		storagemode = strVal(flagValue);
2148

2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165
		if (strcasecmp(storagemode, "plain") == 0)
			newstorage = 'p';
		else if (strcasecmp(storagemode, "external") == 0)
			newstorage = 'e';
		else if (strcasecmp(storagemode, "extended") == 0)
			newstorage = 'x';
		else if (strcasecmp(storagemode, "main") == 0)
			newstorage = 'm';
		else
			elog(ERROR, "ALTER TABLE: \"%s\" storage not recognized",
				 storagemode);
	}
	else
	{
		elog(ERROR, "ALTER TABLE: Invalid column flag: %c",
			 (int) *flagType);
	}
2166 2167

	/*
2168
	 * Propagate to children if desired
2169
	 */
2170
	if (inh)
2171
	{
2172 2173
		List	   *child,
				   *children;
2174

2175 2176
		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);
2177

2178 2179 2180 2181 2182 2183
		/*
		 * find_all_inheritors does the recursive search of the
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
		 */
		foreach(child, children)
2184
		{
2185
			Oid			childrelid = lfirsti(child);
2186

2187 2188 2189 2190
			if (childrelid == myrelid)
				continue;
			AlterTableAlterColumnFlags(childrelid,
									   false, colName, flagValue, flagType);
2191 2192 2193
		}
	}

2194 2195 2196 2197
	/* -= now do the thing on this relation =- */

	attrelation = heap_openr(AttributeRelationName, RowExclusiveLock);

2198
	tuple = SearchSysCacheCopyAttName(myrelid, colName);
2199 2200 2201 2202 2203 2204 2205 2206
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
			 RelationGetRelationName(rel), colName);
	attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);

	if (attrtuple->attnum < 0)
		elog(ERROR, "ALTER TABLE: cannot change system attribute \"%s\"",
			 colName);
2207
	/*
2208
	 * Now change the appropriate field
2209
	 */
2210 2211 2212
	if (*flagType == 'S')
		attrtuple->attstattarget = newtarget;
	else if (*flagType == 'M')
2213
	{
2214 2215 2216 2217 2218 2219 2220 2221 2222
		/*
		 * safety check: do not allow toasted storage modes unless column
		 * datatype is TOAST-aware.
		 */
		if (newstorage == 'p' || TypeIsToastable(attrtuple->atttypid))
			attrtuple->attstorage = newstorage;
		else
			elog(ERROR, "ALTER TABLE: Column datatype %s can only have storage \"plain\"",
				 format_type_be(attrtuple->atttypid));
2223 2224
	}

2225
	simple_heap_update(attrelation, &tuple->t_self, tuple);
2226

2227 2228
	/* keep system catalog indexes current */
	CatalogUpdateIndexes(attrelation, tuple);
2229 2230

	heap_freetuple(tuple);
2231

2232 2233
	heap_close(attrelation, NoLock);
	heap_close(rel, NoLock);	/* close rel, but keep lock! */
2234 2235
}

2236

2237
/*
2238
 * ALTER TABLE DROP COLUMN
2239
 */
2240 2241 2242
void
AlterTableDropColumn(Oid myrelid,
					 bool inh, const char *colName,
2243
					 DropBehavior behavior)
2244
{
2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337
	Relation	rel;
	AttrNumber	attnum;
	AttrNumber	n;
	TupleDesc	tupleDesc;
	bool		success;
	ObjectAddress	object;

	rel = heap_open(myrelid, AccessExclusiveLock);

	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
			 RelationGetRelationName(rel));

	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
			 RelationGetRelationName(rel));

	if (!pg_class_ownercheck(myrelid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));

	/*
	 * get the number of the attribute
	 */
	attnum = get_attnum(myrelid, colName);
	if (attnum == InvalidAttrNumber)
		elog(ERROR, "Relation \"%s\" has no column \"%s\"",
			 RelationGetRelationName(rel), colName);

	/* Can't drop a system attribute */
	if (attnum < 0)
		elog(ERROR, "ALTER TABLE: Cannot drop system attribute \"%s\"",
			 colName);

	/*
	 * Make sure there will be at least one user column left in the relation
	 * after we drop this one.  Zero-length tuples tend to confuse us.
	 */
	tupleDesc = RelationGetDescr(rel);

	success = false;
	for (n = 1; n <= tupleDesc->natts; n++)
	{
		Form_pg_attribute attribute = tupleDesc->attrs[n - 1];

		if (!attribute->attisdropped && n != attnum)
		{
			success = true;
			break;
		}
	}

	if (!success)
		elog(ERROR, "ALTER TABLE: Cannot drop last column from table \"%s\"",
			RelationGetRelationName(rel));

	/*
	 * Propagate to children if desired
	 */
	if (inh)
	{
		List	   *child,
			   *children;

		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);

		/*
		 * find_all_inheritors does the recursive search of the
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
		 */
		foreach(child, children)
		{
			Oid			childrelid = lfirsti(child);

			if (childrelid == myrelid)
				continue;
			AlterTableDropColumn(childrelid,
								false, colName, behavior);
		}
	}

	/*
	 * Perform the actual deletion
	 */
	object.classId = RelOid_pg_class;
	object.objectId = myrelid;
	object.objectSubId = attnum;

	performDeletion(&object, behavior);

	heap_close(rel, NoLock);	/* close rel, but keep lock! */
2338 2339 2340 2341
}


/*
2342
 * ALTER TABLE ADD CONSTRAINT
2343 2344
 */
void
2345 2346 2347 2348 2349
AlterTableAddConstraint(Oid myrelid,
						bool inh, List *newConstraints)
{
	Relation	rel;
	List	   *listptr;
2350
	int			counter = 0;
2351 2352 2353 2354 2355

	/*
	 * Grab an exclusive lock on the target table, which we will NOT
	 * release until end of transaction.
	 */
2356
	rel = heap_open(myrelid, AccessExclusiveLock);
2357

2358 2359 2360
	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
			 RelationGetRelationName(rel));
2361

2362 2363 2364 2365 2366 2367
	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
			 RelationGetRelationName(rel));

	if (!pg_class_ownercheck(myrelid, GetUserId()))
2368
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
2369 2370

	if (inh)
2371 2372 2373 2374 2375
	{
		List	   *child,
				   *children;

		/* this routine is actually in the planner */
2376
		children = find_all_inheritors(myrelid);
2377 2378 2379 2380 2381 2382 2383 2384 2385 2386

		/*
		 * find_all_inheritors does the recursive search of the
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
		 */
		foreach(child, children)
		{
			Oid			childrelid = lfirsti(child);

2387
			if (childrelid == myrelid)
2388
				continue;
2389
			AlterTableAddConstraint(childrelid, false, newConstraints);
2390 2391 2392
		}
	}

2393 2394
	foreach(listptr, newConstraints)
	{
2395 2396 2397 2398 2399 2400
		/*
		 * copy is because we may destructively alter the node below
		 * by inserting a generated name; this name is not necessarily
		 * correct for children or parents.
		 */
		Node	   *newConstraint = copyObject(lfirst(listptr));
2401

2402 2403 2404 2405 2406
		switch (nodeTag(newConstraint))
		{
			case T_Constraint:
				{
					Constraint *constr = (Constraint *) newConstraint;
2407

2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426
					/*
					 * Currently, we only expect to see CONSTR_CHECK nodes
					 * arriving here (see the preprocessing done in
					 * parser/analyze.c).  Use a switch anyway to make it
					 * easier to add more code later.
					 */
					switch (constr->contype)
					{
						case CONSTR_CHECK:
							{
								ParseState *pstate;
								bool		successful = true;
								HeapScanDesc scan;
								ExprContext *econtext;
								TupleTableSlot *slot;
								HeapTuple	tuple;
								RangeTblEntry *rte;
								List	   *qual;
								Node	   *expr;
2427

2428 2429 2430
								/*
								 * Assign or validate constraint name
								 */
2431
								if (constr->name)
2432 2433 2434 2435 2436 2437 2438 2439
								{
									if (ConstraintNameIsUsed(RelationGetRelid(rel),
															 RelationGetNamespace(rel),
															 constr->name))
										elog(ERROR, "constraint \"%s\" already exists for relation \"%s\"",
											 constr->name,
											 RelationGetRelationName(rel));
								}
2440
								else
2441 2442 2443
									constr->name = GenerateConstraintName(RelationGetRelid(rel),
																		  RelationGetNamespace(rel),
																		  &counter);
2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467

								/*
								 * We need to make a parse state and range
								 * table to allow us to transformExpr and
								 * fix_opids to get a version of the
								 * expression we can pass to ExecQual
								 */
								pstate = make_parsestate(NULL);
								rte = addRangeTableEntryForRelation(pstate,
																	myrelid,
											makeAlias(RelationGetRelationName(rel), NIL),
																	false,
																	true);
								addRTEtoQuery(pstate, rte, true, true);

								/*
								 * Convert the A_EXPR in raw_expr into an
								 * EXPR
								 */
								expr = transformExpr(pstate, constr->raw_expr);

								/*
								 * Make sure it yields a boolean result.
								 */
2468
								expr = coerce_to_boolean(expr, "CHECK");
2469 2470 2471 2472 2473 2474 2475 2476 2477

								/*
								 * Make sure no outside relations are
								 * referred to.
								 */
								if (length(pstate->p_rtable) != 1)
									elog(ERROR, "Only relation '%s' can be referenced in CHECK",
										 RelationGetRelationName(rel));

2478 2479 2480 2481 2482 2483 2484 2485
								/*
								 * No subplans or aggregates, either...
								 */
								if (contain_subplans(expr))
									elog(ERROR, "cannot use subselect in CHECK constraint expression");
								if (contain_agg_clause(expr))
									elog(ERROR, "cannot use aggregate function in CHECK constraint expression");

2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506
								/*
								 * Might as well try to reduce any
								 * constant expressions.
								 */
								expr = eval_const_expressions(expr);

								/* And fix the opids */
								fix_opids(expr);

								qual = makeList1(expr);

								/* Make tuple slot to hold tuples */
								slot = MakeTupleTableSlot();
								ExecSetSlotDescriptor(slot, RelationGetDescr(rel), false);
								/* Make an expression context for ExecQual */
								econtext = MakeExprContext(slot, CurrentMemoryContext);

								/*
								 * Scan through the rows now, checking the
								 * expression at each row.
								 */
2507
								scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
2508

2509
								while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525
								{
									ExecStoreTuple(tuple, slot, InvalidBuffer, false);
									if (!ExecQual(qual, econtext, true))
									{
										successful = false;
										break;
									}
									ResetExprContext(econtext);
								}

								heap_endscan(scan);

								FreeExprContext(econtext);
								pfree(slot);

								if (!successful)
2526 2527
									elog(ERROR, "AlterTableAddConstraint: rejected due to CHECK constraint %s",
										 constr->name);
2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549

								/*
								 * Call AddRelationRawConstraints to do
								 * the real adding -- It duplicates some
								 * of the above, but does not check the
								 * validity of the constraint against
								 * tuples already in the table.
								 */
								AddRelationRawConstraints(rel, NIL,
													  makeList1(constr));

								break;
							}
						default:
							elog(ERROR, "ALTER TABLE / ADD CONSTRAINT is not implemented for that constraint type.");
					}
					break;
				}
			case T_FkConstraint:
				{
					FkConstraint *fkconstraint = (FkConstraint *) newConstraint;
					Relation	pkrel;
2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567
					Oid			constrOid;

					/*
					 * Assign or validate constraint name
					 */
					if (fkconstraint->constr_name)
					{
						if (ConstraintNameIsUsed(RelationGetRelid(rel),
												 RelationGetNamespace(rel),
												 fkconstraint->constr_name))
							elog(ERROR, "constraint \"%s\" already exists for relation \"%s\"",
								 fkconstraint->constr_name,
								 RelationGetRelationName(rel));
					}
					else
						fkconstraint->constr_name = GenerateConstraintName(RelationGetRelid(rel),
																		   RelationGetNamespace(rel),
																		   &counter);
2568 2569 2570 2571

					/*
					 * Grab an exclusive lock on the pk table, so that
					 * someone doesn't delete rows out from under us.
2572 2573 2574 2575
					 * (Although a lesser lock would do for that purpose,
					 * we'll need exclusive lock anyway to add triggers
					 * to the pk table; trying to start with a lesser lock
					 * will just create a risk of deadlock.)
2576 2577 2578 2579 2580 2581 2582 2583
					 */
					pkrel = heap_openrv(fkconstraint->pktable,
										AccessExclusiveLock);

					/*
					 * Validity checks
					 */
					if (pkrel->rd_rel->relkind != RELKIND_RELATION)
2584 2585 2586 2587 2588 2589 2590 2591 2592
						elog(ERROR, "referenced relation \"%s\" is not a table",
							 RelationGetRelationName(pkrel));

					if (!allowSystemTableMods
						&& IsSystemRelation(pkrel))
						elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
							 RelationGetRelationName(pkrel));

					/* XXX shouldn't there be a permission check too? */
2593 2594 2595

					if (isTempNamespace(RelationGetNamespace(pkrel)) &&
						!isTempNamespace(RelationGetNamespace(rel)))
2596
						elog(ERROR, "ALTER TABLE / ADD CONSTRAINT: Unable to reference temporary table from permanent table constraint");
2597 2598

					/*
2599 2600
					 * Check that the constraint is satisfied by existing
					 * rows (we can skip this during table creation).
2601 2602 2603 2604 2605 2606
					 *
					 * NOTE: we assume parser has already checked for
					 * existence of an appropriate unique index on the
					 * referenced relation, and that the column datatypes
					 * are comparable.
					 */
2607 2608
					if (!fkconstraint->skip_validation)
						validateForeignKeyConstraint(fkconstraint, rel, pkrel);
2609

2610 2611 2612 2613 2614
					/*
					 * Record the FK constraint in pg_constraint.
					 */
					constrOid = createForeignKeyConstraint(rel, pkrel,
														   fkconstraint);
2615

2616 2617 2618 2619
					/*
					 * Create the triggers that will enforce the constraint.
					 */
					createForeignKeyTriggers(rel, fkconstraint, constrOid);
2620

2621 2622 2623 2624
					/*
					 * Close pk table, but keep lock until we've committed.
					 */
					heap_close(pkrel, NoLock);
2625

2626 2627 2628 2629 2630 2631
					break;
				}
			default:
				elog(ERROR, "ALTER TABLE / ADD CONSTRAINT unable to determine type of constraint passed");
		}
	}
2632

2633 2634 2635
	/* Close rel, but keep lock till commit */
	heap_close(rel, NoLock);
}
2636

2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680
/*
 * Scan the existing rows in a table to verify they meet a proposed FK
 * constraint.
 *
 * Caller must have opened and locked both relations.
 */
static void
validateForeignKeyConstraint(FkConstraint *fkconstraint,
							 Relation rel,
							 Relation pkrel)
{
	HeapScanDesc scan;
	HeapTuple	tuple;
	Trigger		trig;
	List	   *list;
	int			count;

	/*
	 * Scan through each tuple, calling RI_FKey_check_ins
	 * (insert trigger) as if that tuple had just been
	 * inserted.  If any of those fail, it should
	 * elog(ERROR) and that's that.
	 */
	MemSet(&trig, 0, sizeof(trig));
	trig.tgoid = InvalidOid;
	trig.tgname = fkconstraint->constr_name;
	trig.tgenabled = TRUE;
	trig.tgisconstraint = TRUE;
	trig.tgconstrrelid = RelationGetRelid(pkrel);
	trig.tgdeferrable = FALSE;
	trig.tginitdeferred = FALSE;

	trig.tgargs = (char **) palloc(sizeof(char *) *
								   (4 + length(fkconstraint->fk_attrs)
									+ length(fkconstraint->pk_attrs)));

	trig.tgargs[0] = trig.tgname;
	trig.tgargs[1] = RelationGetRelationName(rel);
	trig.tgargs[2] = RelationGetRelationName(pkrel);
	trig.tgargs[3] = fkMatchTypeToString(fkconstraint->fk_matchtype);
	count = 4;
	foreach(list, fkconstraint->fk_attrs)
	{
		Ident	   *fk_at = lfirst(list);
2681

2682 2683 2684 2685 2686 2687 2688
		trig.tgargs[count] = fk_at->name;
		count += 2;
	}
	count = 5;
	foreach(list, fkconstraint->pk_attrs)
	{
		Ident	   *pk_at = lfirst(list);
2689

2690 2691 2692 2693
		trig.tgargs[count] = pk_at->name;
		count += 2;
	}
	trig.tgnargs = count - 1;
2694

2695
	scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
2696

2697 2698 2699 2700
	while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
	{
		FunctionCallInfoData fcinfo;
		TriggerData trigdata;
2701

2702 2703 2704 2705 2706 2707
		/*
		 * Make a call to the trigger function
		 *
		 * No parameters are passed, but we do set a context
		 */
		MemSet(&fcinfo, 0, sizeof(fcinfo));
2708

2709 2710 2711 2712 2713 2714 2715 2716 2717
		/*
		 * We assume RI_FKey_check_ins won't look at flinfo...
		 */
		trigdata.type = T_TriggerData;
		trigdata.tg_event = TRIGGER_EVENT_INSERT | TRIGGER_EVENT_ROW;
		trigdata.tg_relation = rel;
		trigdata.tg_trigtuple = tuple;
		trigdata.tg_newtuple = NULL;
		trigdata.tg_trigger = &trig;
2718

2719 2720 2721
		fcinfo.context = (Node *) &trigdata;

		RI_FKey_check_ins(&fcinfo);
2722 2723
	}

2724 2725 2726
	heap_endscan(scan);

	pfree(trig.tgargs);
2727 2728
}

2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749
/*
 * Record an FK constraint in pg_constraint.
 */
static Oid
createForeignKeyConstraint(Relation rel, Relation pkrel,
						   FkConstraint *fkconstraint)
{
	int16	   *fkattr;
	int16	   *pkattr;
	int			fkcount;
	int			pkcount;
	List	   *l;
	int			i;

	/* Convert foreign-key attr names to attr number array */
	fkcount = length(fkconstraint->fk_attrs);
	fkattr = (int16 *) palloc(fkcount * sizeof(int16));
	i = 0;
	foreach(l, fkconstraint->fk_attrs)
	{
		Ident *id = (Ident *) lfirst(l);
2750
		AttrNumber	attno;
2751

2752 2753 2754 2755 2756
		attno = get_attnum(RelationGetRelid(rel), id->name);
		if (attno == InvalidAttrNumber)
			elog(ERROR, "Relation \"%s\" has no column \"%s\"",
				 RelationGetRelationName(rel), id->name);
		fkattr[i++] = attno;
2757 2758 2759 2760 2761 2762 2763 2764 2765
	}

	/* The same for the referenced primary key attrs */
	pkcount = length(fkconstraint->pk_attrs);
	pkattr = (int16 *) palloc(pkcount * sizeof(int16));
	i = 0;
	foreach(l, fkconstraint->pk_attrs)
	{
		Ident *id = (Ident *) lfirst(l);
2766
		AttrNumber	attno;
2767

2768 2769 2770 2771 2772
		attno = get_attnum(RelationGetRelid(pkrel), id->name);
		if (attno == InvalidAttrNumber)
			elog(ERROR, "Relation \"%s\" has no column \"%s\"",
				 RelationGetRelationName(pkrel), id->name);
		pkattr[i++] = attno;
2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790
	}

	/* Now we can make the pg_constraint entry */
	return CreateConstraintEntry(fkconstraint->constr_name,
								 RelationGetNamespace(rel),
								 CONSTRAINT_FOREIGN,
								 fkconstraint->deferrable,
								 fkconstraint->initdeferred,
								 RelationGetRelid(rel),
								 fkattr,
								 fkcount,
								 InvalidOid, /* not a domain constraint */
								 RelationGetRelid(pkrel),
								 pkattr,
								 pkcount,
								 fkconstraint->fk_upd_action,
								 fkconstraint->fk_del_action,
								 fkconstraint->fk_matchtype,
2791
								 NULL, /* no check constraint */
2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056
								 NULL,
								 NULL);
}

/*
 * Create the triggers that implement an FK constraint.
 */
static void
createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
						 Oid constrOid)
{
	RangeVar   *myRel;
	CreateTrigStmt *fk_trigger;
	List	   *fk_attr;
	List	   *pk_attr;
	Ident	   *id;
	ObjectAddress trigobj,
				constrobj;

	/*
	 * Reconstruct a RangeVar for my relation (not passed in, unfortunately).
	 */
	myRel = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)),
						 RelationGetRelationName(rel));

	/*
	 * Preset objectAddress fields
	 */
	constrobj.classId = get_system_catalog_relid(ConstraintRelationName);
	constrobj.objectId = constrOid;
	constrobj.objectSubId = 0;
	trigobj.classId = get_system_catalog_relid(TriggerRelationName);
	trigobj.objectSubId = 0;

	/* Make changes-so-far visible */
	CommandCounterIncrement();

	/*
	 * Build and execute a CREATE CONSTRAINT TRIGGER statement for the
	 * CHECK action.
	 */
	fk_trigger = makeNode(CreateTrigStmt);
	fk_trigger->trigname = fkconstraint->constr_name;
	fk_trigger->relation = myRel;
	fk_trigger->funcname = SystemFuncName("RI_FKey_check_ins");
	fk_trigger->before = false;
	fk_trigger->row = true;
	fk_trigger->actions[0] = 'i';
	fk_trigger->actions[1] = 'u';
	fk_trigger->actions[2] = '\0';
	fk_trigger->lang = NULL;
	fk_trigger->text = NULL;

	fk_trigger->attr = NIL;
	fk_trigger->when = NULL;
	fk_trigger->isconstraint = true;
	fk_trigger->deferrable = fkconstraint->deferrable;
	fk_trigger->initdeferred = fkconstraint->initdeferred;
	fk_trigger->constrrel = fkconstraint->pktable;

	fk_trigger->args = NIL;
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(fkconstraint->constr_name));
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(myRel->relname));
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(fkconstraint->pktable->relname));
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(fkMatchTypeToString(fkconstraint->fk_matchtype)));
	fk_attr = fkconstraint->fk_attrs;
	pk_attr = fkconstraint->pk_attrs;
	if (length(fk_attr) != length(pk_attr))
		elog(ERROR, "number of key attributes in referenced table must be equal to foreign key"
			 "\n\tIllegal FOREIGN KEY definition references \"%s\"",
			 fkconstraint->pktable->relname);

	while (fk_attr != NIL)
	{
		id = (Ident *) lfirst(fk_attr);
		fk_trigger->args = lappend(fk_trigger->args, makeString(id->name));

		id = (Ident *) lfirst(pk_attr);
		fk_trigger->args = lappend(fk_trigger->args, makeString(id->name));

		fk_attr = lnext(fk_attr);
		pk_attr = lnext(pk_attr);
	}

	trigobj.objectId = CreateTrigger(fk_trigger, true);

	/* Register dependency from trigger to constraint */
	recordDependencyOn(&trigobj, &constrobj, DEPENDENCY_INTERNAL);

	/* Make changes-so-far visible */
	CommandCounterIncrement();

	/*
	 * Build and execute a CREATE CONSTRAINT TRIGGER statement for the
	 * ON DELETE action on the referenced table.
	 */
	fk_trigger = makeNode(CreateTrigStmt);
	fk_trigger->trigname = fkconstraint->constr_name;
	fk_trigger->relation = fkconstraint->pktable;
	fk_trigger->before = false;
	fk_trigger->row = true;
	fk_trigger->actions[0] = 'd';
	fk_trigger->actions[1] = '\0';
	fk_trigger->lang = NULL;
	fk_trigger->text = NULL;

	fk_trigger->attr = NIL;
	fk_trigger->when = NULL;
	fk_trigger->isconstraint = true;
	fk_trigger->deferrable = fkconstraint->deferrable;
	fk_trigger->initdeferred = fkconstraint->initdeferred;
	fk_trigger->constrrel = myRel;
	switch (fkconstraint->fk_del_action)
	{
		case FKCONSTR_ACTION_NOACTION:
			fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_del");
			break;
		case FKCONSTR_ACTION_RESTRICT:
			fk_trigger->deferrable = false;
			fk_trigger->initdeferred = false;
			fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_del");
			break;
		case FKCONSTR_ACTION_CASCADE:
			fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_del");
			break;
		case FKCONSTR_ACTION_SETNULL:
			fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_del");
			break;
		case FKCONSTR_ACTION_SETDEFAULT:
			fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_del");
			break;
		default:
			elog(ERROR, "Unrecognized ON DELETE action for FOREIGN KEY constraint");
			break;
	}

	fk_trigger->args = NIL;
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(fkconstraint->constr_name));
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(myRel->relname));
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(fkconstraint->pktable->relname));
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(fkMatchTypeToString(fkconstraint->fk_matchtype)));
	fk_attr = fkconstraint->fk_attrs;
	pk_attr = fkconstraint->pk_attrs;
	while (fk_attr != NIL)
	{
		id = (Ident *) lfirst(fk_attr);
		fk_trigger->args = lappend(fk_trigger->args, makeString(id->name));

		id = (Ident *) lfirst(pk_attr);
		fk_trigger->args = lappend(fk_trigger->args, makeString(id->name));

		fk_attr = lnext(fk_attr);
		pk_attr = lnext(pk_attr);
	}

	trigobj.objectId = CreateTrigger(fk_trigger, true);

	/* Register dependency from trigger to constraint */
	recordDependencyOn(&trigobj, &constrobj, DEPENDENCY_INTERNAL);

	/* Make changes-so-far visible */
	CommandCounterIncrement();

	/*
	 * Build and execute a CREATE CONSTRAINT TRIGGER statement for the
	 * ON UPDATE action on the referenced table.
	 */
	fk_trigger = makeNode(CreateTrigStmt);
	fk_trigger->trigname = fkconstraint->constr_name;
	fk_trigger->relation = fkconstraint->pktable;
	fk_trigger->before = false;
	fk_trigger->row = true;
	fk_trigger->actions[0] = 'u';
	fk_trigger->actions[1] = '\0';
	fk_trigger->lang = NULL;
	fk_trigger->text = NULL;

	fk_trigger->attr = NIL;
	fk_trigger->when = NULL;
	fk_trigger->isconstraint = true;
	fk_trigger->deferrable = fkconstraint->deferrable;
	fk_trigger->initdeferred = fkconstraint->initdeferred;
	fk_trigger->constrrel = myRel;
	switch (fkconstraint->fk_upd_action)
	{
		case FKCONSTR_ACTION_NOACTION:
			fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_upd");
			break;
		case FKCONSTR_ACTION_RESTRICT:
			fk_trigger->deferrable = false;
			fk_trigger->initdeferred = false;
			fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_upd");
			break;
		case FKCONSTR_ACTION_CASCADE:
			fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_upd");
			break;
		case FKCONSTR_ACTION_SETNULL:
			fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_upd");
			break;
		case FKCONSTR_ACTION_SETDEFAULT:
			fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_upd");
			break;
		default:
			elog(ERROR, "Unrecognized ON UPDATE action for FOREIGN KEY constraint");
			break;
	}

	fk_trigger->args = NIL;
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(fkconstraint->constr_name));
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(myRel->relname));
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(fkconstraint->pktable->relname));
	fk_trigger->args = lappend(fk_trigger->args,
							   makeString(fkMatchTypeToString(fkconstraint->fk_matchtype)));
	fk_attr = fkconstraint->fk_attrs;
	pk_attr = fkconstraint->pk_attrs;
	while (fk_attr != NIL)
	{
		id = (Ident *) lfirst(fk_attr);
		fk_trigger->args = lappend(fk_trigger->args, makeString(id->name));

		id = (Ident *) lfirst(pk_attr);
		fk_trigger->args = lappend(fk_trigger->args, makeString(id->name));

		fk_attr = lnext(fk_attr);
		pk_attr = lnext(pk_attr);
	}

	trigobj.objectId = CreateTrigger(fk_trigger, true);

	/* Register dependency from trigger to constraint */
	recordDependencyOn(&trigobj, &constrobj, DEPENDENCY_INTERNAL);
}

/*
 * fkMatchTypeToString -
 *	  convert FKCONSTR_MATCH_xxx code to string to use in trigger args
 */
static char *
fkMatchTypeToString(char match_type)
{
	switch (match_type) 
	{
		case FKCONSTR_MATCH_FULL:
			return pstrdup("FULL");
		case FKCONSTR_MATCH_PARTIAL:
			return pstrdup("PARTIAL");
		case FKCONSTR_MATCH_UNSPECIFIED:
			return pstrdup("UNSPECIFIED");
		default:
			elog(ERROR, "fkMatchTypeToString: Unknown MATCH TYPE '%c'",
				 match_type);
	}
	return NULL;				/* can't get here */
}
3057

3058
/*
3059
 * ALTER TABLE DROP CONSTRAINT
3060 3061
 */
void
3062 3063
AlterTableDropConstraint(Oid myrelid,
						 bool inh, const char *constrName,
3064
						 DropBehavior behavior)
3065
{
3066
	Relation	rel;
3067
	int			deleted = 0;
3068 3069

	/*
3070 3071
	 * Acquire an exclusive lock on the target relation for the duration
	 * of the operation.
3072
	 */
3073
	rel = heap_open(myrelid, AccessExclusiveLock);
3074

3075 3076 3077 3078
	/* Disallow DROP CONSTRAINT on views, indexes, sequences, etc */
	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
			 RelationGetRelationName(rel));
3079

3080 3081 3082 3083 3084 3085
	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
			 RelationGetRelationName(rel));

	if (!pg_class_ownercheck(myrelid, GetUserId()))
3086
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
3087 3088

	/*
3089
	 * Process child tables if requested.
3090
	 */
3091 3092 3093 3094
	if (inh)
	{
		List	   *child,
				   *children;
3095

3096 3097
		/* This routine is actually in the planner */
		children = find_all_inheritors(myrelid);
3098

3099 3100 3101 3102 3103 3104 3105 3106 3107
		/*
		 * find_all_inheritors does the recursive search of the
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
		 */
		foreach(child, children)
		{
			Oid			childrelid = lfirsti(child);
			Relation	inhrel;
3108

3109 3110 3111 3112 3113 3114 3115 3116
			if (childrelid == myrelid)
				continue;
			inhrel = heap_open(childrelid, AccessExclusiveLock);
			/* do NOT count child constraints in deleted. */
			RemoveRelConstraints(inhrel, constrName, behavior);
			heap_close(inhrel, NoLock);
		}
	}
3117 3118

	/*
3119
	 * Now do the thing on this relation.
3120
	 */
3121
	deleted += RemoveRelConstraints(rel, constrName, behavior);
3122

3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136
	/* Close the target relation */
	heap_close(rel, NoLock);

	/* If zero constraints deleted, complain */
	if (deleted == 0)
		elog(ERROR, "ALTER TABLE / DROP CONSTRAINT: %s does not exist",
			 constrName);
	/* Otherwise if more than one constraint deleted, notify */
	else if (deleted > 1)
		elog(NOTICE, "Multiple constraints dropped");
}

/*
 * ALTER TABLE OWNER
3137
 */
3138 3139
void
AlterTableOwner(Oid relationOid, int32 newOwnerSysId)
3140
{
3141 3142 3143 3144
	Relation		target_rel;
	Relation		class_rel;
	HeapTuple		tuple;
	Form_pg_class	tuple_class;
3145

3146
	/* Get exclusive lock till end of transaction on the target table */
3147 3148
	/* Use relation_open here so that we work on indexes... */
	target_rel = relation_open(relationOid, AccessExclusiveLock);
3149

3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161
	/* Get its pg_class tuple, too */
	class_rel = heap_openr(RelationRelationName, RowExclusiveLock);

	tuple = SearchSysCacheCopy(RELOID,
							   ObjectIdGetDatum(relationOid),
							   0, 0, 0);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "ALTER TABLE: relation %u not found", relationOid);
	tuple_class = (Form_pg_class) GETSTRUCT(tuple);

	/* Can we change the ownership of this tuple? */
	CheckTupleType(tuple_class);
3162 3163

	/*
3164 3165
	 * Okay, this is a valid tuple: change its ownership and
	 * write to the heap.
3166
	 */
3167 3168
	tuple_class->relowner = newOwnerSysId;
	simple_heap_update(class_rel, &tuple->t_self, tuple);
3169

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	/* Keep the catalog indexes up to date */
	CatalogUpdateIndexes(class_rel, tuple);
3172 3173

	/*
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	 * If we are operating on a table, also change the ownership of any
	 * indexes that belong to the table, as well as the table's toast
	 * table (if it has one)
3177
	 */
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	if (tuple_class->relkind == RELKIND_RELATION ||
		tuple_class->relkind == RELKIND_TOASTVALUE)
3180
	{
3181
		List *index_oid_list, *i;
3182

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		/* Find all the indexes belonging to this relation */
		index_oid_list = RelationGetIndexList(target_rel);
3185

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		/* For each index, recursively change its ownership */
		foreach(i, index_oid_list)
		{
			AlterTableOwner(lfirsti(i), newOwnerSysId);
		}
3191

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		freeList(index_oid_list);
	}
3194

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	if (tuple_class->relkind == RELKIND_RELATION)
	{
		/* If it has a toast table, recurse to change its ownership */
		if (tuple_class->reltoastrelid != InvalidOid)
		{
			AlterTableOwner(tuple_class->reltoastrelid, newOwnerSysId);
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		}
	}

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	heap_freetuple(tuple);
	heap_close(class_rel, RowExclusiveLock);
3206
	relation_close(target_rel, NoLock);
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}

3209 3210
static void
CheckTupleType(Form_pg_class tuple_class)
3211
{
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	switch (tuple_class->relkind)
3213
	{
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		case RELKIND_RELATION:
		case RELKIND_INDEX:
		case RELKIND_VIEW:
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3217
		case RELKIND_COMPOSITE_TYPE:
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		case RELKIND_SEQUENCE:
		case RELKIND_TOASTVALUE:
			/* ok to change owner */
			break;
		default:
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3223
			elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table, TOAST table, index, view, type, or sequence",
3224
				 NameStr(tuple_class->relname));
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	}
}

/*
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 * ALTER TABLE CREATE TOAST TABLE
3230
 */
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void
AlterTableCreateToastTable(Oid relOid, bool silent)
3233
{
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	Relation	rel;
	HeapTuple	reltup;
	HeapTupleData classtuple;
	TupleDesc	tupdesc;
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	bool		shared_relation;
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	Relation	class_rel;
	Buffer		buffer;
	Oid			toast_relid;
	Oid			toast_idxid;
	char		toast_relname[NAMEDATALEN];
	char		toast_idxname[NAMEDATALEN];
	IndexInfo  *indexInfo;
	Oid			classObjectId[2];
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	ObjectAddress baseobject,
				toastobject;
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	/*
	 * Grab an exclusive lock on the target table, which we will NOT
	 * release until end of transaction.
	 */
	rel = heap_open(relOid, AccessExclusiveLock);
3255

3256
	/* Check permissions */
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	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
			 RelationGetRelationName(rel));
3260

3261
	if (!pg_class_ownercheck(relOid, GetUserId()))
3262
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
3263

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	/*
	 * Toast table is shared if and only if its parent is.
	 *
	 * We cannot allow toasting a shared relation after initdb (because
	 * there's no way to mark it toasted in other databases' pg_class).
	 * Unfortunately we can't distinguish initdb from a manually started
	 * standalone backend.  However, we can at least prevent this mistake
	 * under normal multi-user operation.
	 */
	shared_relation = rel->rd_rel->relisshared;
	if (shared_relation && IsUnderPostmaster)
		elog(ERROR, "Shared relations cannot be toasted after initdb");

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	/*
	 * lock the pg_class tuple for update (is that really needed?)
	 */
	class_rel = heap_openr(RelationRelationName, RowExclusiveLock);
3281

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	reltup = SearchSysCache(RELOID,
							ObjectIdGetDatum(relOid),
							0, 0, 0);
	if (!HeapTupleIsValid(reltup))
		elog(ERROR, "ALTER TABLE: relation \"%s\" not found",
			 RelationGetRelationName(rel));
	classtuple.t_self = reltup->t_self;
	ReleaseSysCache(reltup);

3291 3292
	switch (heap_mark4update(class_rel, &classtuple, &buffer,
							 GetCurrentCommandId()))
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	{
		case HeapTupleSelfUpdated:
		case HeapTupleMayBeUpdated:
			break;
		default:
			elog(ERROR, "couldn't lock pg_class tuple");
	}
	reltup = heap_copytuple(&classtuple);
	ReleaseBuffer(buffer);

	/*
	 * Is it already toasted?
	 */
	if (((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid != InvalidOid)
	{
		if (silent)
3309
		{
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			heap_close(rel, NoLock);
			heap_close(class_rel, NoLock);
			heap_freetuple(reltup);
			return;
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		}

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		elog(ERROR, "ALTER TABLE: relation \"%s\" already has a toast table",
			 RelationGetRelationName(rel));
	}
3319

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	/*
	 * Check to see whether the table actually needs a TOAST table.
	 */
	if (!needs_toast_table(rel))
	{
		if (silent)
3326
		{
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			heap_close(rel, NoLock);
			heap_close(class_rel, NoLock);
			heap_freetuple(reltup);
			return;
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		}

3333 3334 3335
		elog(ERROR, "ALTER TABLE: relation \"%s\" does not need a toast table",
			 RelationGetRelationName(rel));
	}
3336

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	/*
	 * Create the toast table and its index
	 */
	sprintf(toast_relname, "pg_toast_%u", relOid);
	sprintf(toast_idxname, "pg_toast_%u_index", relOid);
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3343
	/* this is pretty painful...  need a tuple descriptor */
3344
	tupdesc = CreateTemplateTupleDesc(3, WITHOUTOID);
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	TupleDescInitEntry(tupdesc, (AttrNumber) 1,
					   "chunk_id",
					   OIDOID,
					   -1, 0, false);
	TupleDescInitEntry(tupdesc, (AttrNumber) 2,
					   "chunk_seq",
					   INT4OID,
					   -1, 0, false);
	TupleDescInitEntry(tupdesc, (AttrNumber) 3,
					   "chunk_data",
					   BYTEAOID,
					   -1, 0, false);
3357

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	/*
	 * Ensure that the toast table doesn't itself get toasted, or we'll be
	 * toast :-(.  This is essential for chunk_data because type bytea is
	 * toastable; hit the other two just to be sure.
	 */
	tupdesc->attrs[0]->attstorage = 'p';
	tupdesc->attrs[1]->attstorage = 'p';
	tupdesc->attrs[2]->attstorage = 'p';
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3367 3368 3369 3370 3371 3372 3373 3374 3375 3376
	/*
	 * Note: the toast relation is placed in the regular pg_toast namespace
	 * even if its master relation is a temp table.  There cannot be any
	 * naming collision, and the toast rel will be destroyed when its master
	 * is, so there's no need to handle the toast rel as temp.
	 */
	toast_relid = heap_create_with_catalog(toast_relname,
										   PG_TOAST_NAMESPACE,
										   tupdesc,
										   RELKIND_TOASTVALUE,
3377
										   shared_relation,
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										   false,
										   true);
3380

3381 3382
	/* make the toast relation visible, else index creation will fail */
	CommandCounterIncrement();
3383

3384 3385 3386 3387 3388 3389 3390 3391 3392 3393
	/*
	 * Create unique index on chunk_id, chunk_seq.
	 *
	 * NOTE: the tuple toaster could actually function with a single-column
	 * index on chunk_id only.	However, it couldn't be unique then.  We
	 * want it to be unique as a check against the possibility of
	 * duplicate TOAST chunk OIDs.	Too, the index might be a little more
	 * efficient this way, since btree isn't all that happy with large
	 * numbers of equal keys.
	 */
3394

3395 3396 3397 3398 3399 3400 3401 3402
	indexInfo = makeNode(IndexInfo);
	indexInfo->ii_NumIndexAttrs = 2;
	indexInfo->ii_NumKeyAttrs = 2;
	indexInfo->ii_KeyAttrNumbers[0] = 1;
	indexInfo->ii_KeyAttrNumbers[1] = 2;
	indexInfo->ii_Predicate = NIL;
	indexInfo->ii_FuncOid = InvalidOid;
	indexInfo->ii_Unique = true;
3403

3404 3405
	classObjectId[0] = OID_BTREE_OPS_OID;
	classObjectId[1] = INT4_BTREE_OPS_OID;
3406

3407 3408
	toast_idxid = index_create(toast_relid, toast_idxname, indexInfo,
							   BTREE_AM_OID, classObjectId,
3409
							   true, false, true);
3410

3411 3412 3413 3414 3415 3416
	/*
	 * Update toast rel's pg_class entry to show that it has an index. The
	 * index OID is stored into the reltoastidxid field for easy access by
	 * the tuple toaster.
	 */
	setRelhasindex(toast_relid, true, true, toast_idxid);
3417 3418

	/*
3419 3420 3421
	 * Store the toast table's OID in the parent relation's tuple
	 */
	((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;
3422

3423 3424
	simple_heap_update(class_rel, &reltup->t_self, reltup);

3425 3426
	/* Keep catalog indexes current */
	CatalogUpdateIndexes(class_rel, reltup);
3427 3428 3429

	heap_freetuple(reltup);

3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442
	/*
	 * Register dependency from the toast table to the master, so that
	 * the toast table will be deleted if the master is.
	 */
	baseobject.classId = RelOid_pg_class;
	baseobject.objectId = relOid;
	baseobject.objectSubId = 0;
	toastobject.classId = RelOid_pg_class;
	toastobject.objectId = toast_relid;
	toastobject.objectSubId = 0;

	recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);

3443 3444
	/*
	 * Close relations and make changes visible
3445
	 */
3446 3447 3448
	heap_close(class_rel, NoLock);
	heap_close(rel, NoLock);

3449
	CommandCounterIncrement();
3450
}
3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501

/*
 * Check to see whether the table needs a TOAST table.	It does only if
 * (1) there are any toastable attributes, and (2) the maximum length
 * of a tuple could exceed TOAST_TUPLE_THRESHOLD.  (We don't want to
 * create a toast table for something like "f1 varchar(20)".)
 */
static bool
needs_toast_table(Relation rel)
{
	int32		data_length = 0;
	bool		maxlength_unknown = false;
	bool		has_toastable_attrs = false;
	TupleDesc	tupdesc;
	Form_pg_attribute *att;
	int32		tuple_length;
	int			i;

	tupdesc = rel->rd_att;
	att = tupdesc->attrs;

	for (i = 0; i < tupdesc->natts; i++)
	{
		data_length = att_align(data_length, att[i]->attlen, att[i]->attalign);
		if (att[i]->attlen >= 0)
		{
			/* Fixed-length types are never toastable */
			data_length += att[i]->attlen;
		}
		else
		{
			int32		maxlen = type_maximum_size(att[i]->atttypid,
												   att[i]->atttypmod);

			if (maxlen < 0)
				maxlength_unknown = true;
			else
				data_length += maxlen;
			if (att[i]->attstorage != 'p')
				has_toastable_attrs = true;
		}
	}
	if (!has_toastable_attrs)
		return false;			/* nothing to toast? */
	if (maxlength_unknown)
		return true;			/* any unlimited-length attrs? */
	tuple_length = MAXALIGN(offsetof(HeapTupleHeaderData, t_bits) +
							BITMAPLEN(tupdesc->natts)) +
		MAXALIGN(data_length);
	return (tuple_length > TOAST_TUPLE_THRESHOLD);
}