tablecmds.c 93.8 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 1.22 2002/07/16 05:53:33 tgl 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
	 * be working yet; also, always allow if it's a temp table.
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	 */
	namespaceId = RangeVarGetCreationNamespace(stmt->relation);
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	if (!IsBootstrapProcessingMode() && !isTempNamespace(namespaceId))
	{
		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);

	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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	 * 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);
		RawColumnDefault *rawEnt;
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		attnum++;
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		if (colDef->raw_default == NULL)
			continue;
		Assert(colDef->cooked_default == NULL);
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		rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
		rawEnt->attnum = attnum;
		rawEnt->raw_default = colDef->raw_default;
		rawDefaults = lappend(rawDefaults, rawEnt);
	}
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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:
 *				  Rows are removed, indices 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 (!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
		 * for parents after the first one.)
		 */
		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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			/*
			 * 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;
				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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				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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	/*
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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.
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	 */
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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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683
	/*
684 685
	 * If we found any conflicting parent default values, check to make
	 * sure they were overridden by the child.
686
	 */
687
	if (have_bogus_defaults)
688
	{
689
		foreach(entry, schema)
690
		{
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			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().
 *
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 * 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))
721
	{
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		Var		   *var = (Var *) node;
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		if (var->varlevelsup == 0 && var->varno == 1 &&
			var->varattno > 0)
726
		{
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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];
734
		}
735
		return false;
736
	}
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	return expression_tree_walker(node, change_varattnos_walker,
								  (void *) newattno);
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}

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static bool
change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
743
{
744
	return change_varattnos_walker(node, newattno);
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}

747
/*
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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)
756
{
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	Relation	relation;
	TupleDesc	desc;
	int16		seqNumber;
	List	   *entry;
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	HeapTuple	tuple;
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763
	/*
764
	 * sanity checks
765
	 */
766
	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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795
		tuple = heap_formtuple(desc, datum, nullarr);
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		simple_heap_insert(relation, tuple);
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		if (RelationGetForm(relation)->relhasindex)
800
		{
801
			Relation	idescs[Num_pg_inherits_indices];
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			CatalogOpenIndices(Num_pg_inherits_indices, Name_pg_inherits_indices, idescs);
			CatalogIndexInsert(idescs, Num_pg_inherits_indices, relation, tuple);
			CatalogCloseIndices(Num_pg_inherits_indices, idescs);
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		}

808
		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);

822 823
		seqNumber += 1;
	}
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825
	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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	}

872 873 874 875 876 877 878 879
	/*
	 * 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;
		}
	}
}
904 905

/*
906 907 908 909
 * 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.
910
 */
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static int
findAttrByName(const char *attributeName, List *schema)
913
{
914 915 916 917 918 919 920 921 922 923 924 925
	List	   *s;
	int			i = 0;

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

		++i;
		if (strcmp(attributeName, def->colname) == 0)
			return i;
	}
	return 0;
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}
927

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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;
	Relation	idescs[Num_pg_class_indices];

	/*
	 * 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);

	/* keep the catalog indices up to date */
	CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs);
	CatalogIndexInsert(idescs, Num_pg_class_indices, relationRelation, tuple);
	CatalogCloseIndices(Num_pg_class_indices, idescs);

	heap_freetuple(tuple);
	heap_close(relationRelation, RowExclusiveLock);
}
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961
/*
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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
974
 */
975
void
976 977 978 979
renameatt(Oid relid,
		  const char *oldattname,
		  const char *newattname,
		  bool recurse)
980
{
981 982 983 984 985
	Relation	targetrelation;
	Relation	attrelation;
	HeapTuple	atttup;
	List	   *indexoidlist;
	List	   *indexoidscan;
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987 988 989 990
	/*
	 * Grab an exclusive lock on the target table, which we will NOT
	 * release until end of transaction.
	 */
991
	targetrelation = heap_open(relid, AccessExclusiveLock);
992

993 994 995 996 997 998 999 1000 1001 1002 1003
	/*
	 * 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()))
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		aclcheck_error(ACLCHECK_NOT_OWNER,
					   RelationGetRelationName(targetrelation));
1006

1007 1008 1009 1010 1011 1012 1013 1014 1015 1016
	/*
	 * 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)
1017
	{
1018 1019 1020 1021
		List	   *child,
				   *children;

		/* this routine is actually in the planner */
1022
		children = find_all_inheritors(relid);
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		/*
		 * find_all_inheritors does the recursive search of the
1026 1027
		 * inheritance hierarchy, so all we have to do is process all of
		 * the relids in the list that it returns.
1028 1029 1030 1031 1032
		 */
		foreach(child, children)
		{
			Oid			childrelid = lfirsti(child);

1033
			if (childrelid == relid)
1034
				continue;
1035 1036
			/* note we need not recurse again! */
			renameatt(childrelid, oldattname, newattname, false);
1037 1038 1039
		}
	}

1040
	attrelation = heap_openr(AttributeRelationName, RowExclusiveLock);
1041

1042 1043 1044 1045 1046 1047
	atttup = SearchSysCacheCopy(ATTNAME,
								ObjectIdGetDatum(relid),
								PointerGetDatum(oldattname),
								0, 0);
	if (!HeapTupleIsValid(atttup))
		elog(ERROR, "renameatt: attribute \"%s\" does not exist", oldattname);
1048

1049 1050
	if (((Form_pg_attribute) GETSTRUCT(atttup))->attnum < 0)
		elog(ERROR, "renameatt: system attribute \"%s\" not renamed", oldattname);
1051

1052 1053 1054 1055 1056 1057
	/* should not already exist */
	if (SearchSysCacheExists(ATTNAME,
							 ObjectIdGetDatum(relid),
							 PointerGetDatum(newattname),
							 0, 0))
		elog(ERROR, "renameatt: attribute \"%s\" exists", newattname);
1058

1059 1060
	namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
			   newattname);
1061

1062
	simple_heap_update(attrelation, &atttup->t_self, atttup);
1063

1064 1065 1066
	/* keep system catalog indices current */
	{
		Relation	irelations[Num_pg_attr_indices];
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1068 1069 1070 1071
		CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, irelations);
		CatalogIndexInsert(irelations, Num_pg_attr_indices, attrelation, atttup);
		CatalogCloseIndices(Num_pg_attr_indices, irelations);
	}
1072

1073
	heap_freetuple(atttup);
1074

1075 1076 1077 1078 1079
	/*
	 * Update column names of indexes that refer to the column being
	 * renamed.
	 */
	indexoidlist = RelationGetIndexList(targetrelation);
1080

1081 1082 1083 1084
	foreach(indexoidscan, indexoidlist)
	{
		Oid			indexoid = lfirsti(indexoidscan);
		HeapTuple	indextup;
1085

1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100
		/*
		 * 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);
1101

1102 1103 1104 1105 1106 1107 1108 1109 1110 1111
		/*
		 * Okay, look to see if any column name of the index matches the
		 * old attribute name.
		 */
		atttup = SearchSysCacheCopy(ATTNAME,
									ObjectIdGetDatum(indexoid),
									PointerGetDatum(oldattname),
									0, 0);
		if (!HeapTupleIsValid(atttup))
			continue;			/* Nope, so ignore it */
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1113 1114 1115 1116 1117
		/*
		 * Update the (copied) attribute tuple.
		 */
		namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
				   newattname);
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1119
		simple_heap_update(attrelation, &atttup->t_self, atttup);
1120

1121 1122 1123
		/* keep system catalog indices current */
		{
			Relation	irelations[Num_pg_attr_indices];
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1125 1126 1127 1128 1129 1130
			CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, irelations);
			CatalogIndexInsert(irelations, Num_pg_attr_indices, attrelation, atttup);
			CatalogCloseIndices(Num_pg_attr_indices, irelations);
		}
		heap_freetuple(atttup);
	}
1131

1132
	freeList(indexoidlist);
1133

1134
	heap_close(attrelation, RowExclusiveLock);
1135

1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148
	/*
	 * 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);
1149 1150
	}

1151
	heap_close(targetrelation, NoLock); /* close rel but keep lock! */
1152 1153
}

1154
/*
1155 1156 1157 1158 1159 1160 1161
 *		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.
1162 1163
 */
void
1164
renamerel(Oid relid, const char *newrelname)
1165
{
1166 1167 1168 1169 1170 1171 1172 1173
	Relation	targetrelation;
	Relation	relrelation;	/* for RELATION relation */
	HeapTuple	reltup;
	Oid			namespaceId;
	char	   *oldrelname;
	char		relkind;
	bool		relhastriggers;
	Relation	irelations[Num_pg_class_indices];
1174

1175
	/*
1176 1177
	 * Grab an exclusive lock on the target table or index, which we will
	 * NOT release until end of transaction.
1178
	 */
1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191
	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);
1192 1193

	/*
1194 1195
	 * Find relation's pg_class tuple, and make sure newrelname isn't in
	 * use.
1196
	 */
1197
	relrelation = heap_openr(RelationRelationName, RowExclusiveLock);
1198

1199 1200 1201 1202 1203 1204
	reltup = SearchSysCacheCopy(RELOID,
								PointerGetDatum(relid),
								0, 0, 0);
	if (!HeapTupleIsValid(reltup))
		elog(ERROR, "renamerel: relation \"%s\" does not exist",
			 oldrelname);
1205

1206 1207
	if (get_relname_relid(newrelname, namespaceId) != InvalidOid)
		elog(ERROR, "renamerel: relation \"%s\" exists", newrelname);
1208

1209
	/*
1210 1211
	 * Update pg_class tuple with new relname.	(Scribbling on reltup is
	 * OK because it's a copy...)
1212
	 */
1213
	namestrcpy(&(((Form_pg_class) GETSTRUCT(reltup))->relname), newrelname);
1214

1215 1216 1217 1218 1219 1220 1221 1222 1223
	simple_heap_update(relrelation, &reltup->t_self, reltup);

	/* keep the system catalog indices current */
	CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, irelations);
	CatalogIndexInsert(irelations, Num_pg_class_indices, relrelation, reltup);
	CatalogCloseIndices(Num_pg_class_indices, irelations);

	heap_close(relrelation, NoLock);
	heap_freetuple(reltup);
1224 1225

	/*
1226
	 * Also rename the associated type, if any.
1227
	 */
1228 1229
	if (relkind != RELKIND_INDEX)
		TypeRename(oldrelname, namespaceId, newrelname);
1230

1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246
	/*
	 * 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);
	}
1247 1248

	/*
1249
	 * Close rel, but keep exclusive lock!
1250
	 */
1251 1252
	relation_close(targetrelation, NoLock);
}
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/*
 * 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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		{
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			Relation	irelations[Num_pg_attr_indices];

			CatalogOpenIndices(Num_pg_trigger_indices, Name_pg_trigger_indices, irelations);
			CatalogIndexInsert(irelations, Num_pg_trigger_indices, tgrel, tuple);
			CatalogCloseIndices(Num_pg_trigger_indices, irelations);
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		}

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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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	/*
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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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	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,
									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);
	attribute->atttypid = typeTuple->t_data->t_oid;
	attribute->attstattarget = DEFAULT_ATTSTATTARGET;
	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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	ReleaseSysCache(typeTuple);
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	simple_heap_insert(attrdesc, attributeTuple);
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	/* Update indexes on pg_attribute */
	if (RelationGetForm(attrdesc)->relhasindex)
	{
		Relation	idescs[Num_pg_attr_indices];

		CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, idescs);
		CatalogIndexInsert(idescs, Num_pg_attr_indices, attrdesc, attributeTuple);
		CatalogCloseIndices(Num_pg_attr_indices, idescs);
	}

	heap_close(attrdesc, RowExclusiveLock);
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	/*
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	 * Update number of attributes in pg_class tuple
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	 */
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	newreltup = heap_copytuple(reltup);
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	((Form_pg_class) GETSTRUCT(newreltup))->relnatts = maxatts;
	simple_heap_update(pgclass, &newreltup->t_self, newreltup);
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	/* keep catalog indices current */
	if (RelationGetForm(pgclass)->relhasindex)
	{
		Relation	ridescs[Num_pg_class_indices];
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		CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, ridescs);
		CatalogIndexInsert(ridescs, Num_pg_class_indices, pgclass, newreltup);
		CatalogCloseIndices(Num_pg_class_indices, ridescs);
	}
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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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	/*
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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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}

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/*
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 * ALTER TABLE ALTER COLUMN DROP NOT NULL
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 */
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void
AlterTableAlterColumnDropNotNull(Oid myrelid,
								 bool inh, const char *colName)
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{
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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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	tuple = SearchSysCache(ATTNAME,
						   ObjectIdGetDatum(myrelid),
						   PointerGetDatum(colName),
						   0, 0);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
			 RelationGetRelationName(rel), colName);
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	attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
	ReleaseSysCache(tuple);
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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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	/* Loop over all indices on the relation */
	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
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	 */
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	attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);
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	tuple = SearchSysCacheCopy(ATTNAME,
							   ObjectIdGetDatum(myrelid),
							   PointerGetDatum(colName),
							   0, 0);
	if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
		elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
			 RelationGetRelationName(rel), colName);
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	((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = FALSE;
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	simple_heap_update(attr_rel, &tuple->t_self, tuple);
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	/* keep the system catalog indices current */
	if (RelationGetForm(attr_rel)->relhasindex)
	{
		Relation	idescs[Num_pg_attr_indices];
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		CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, idescs);
		CatalogIndexInsert(idescs, Num_pg_attr_indices, attr_rel, tuple);
		CatalogCloseIndices(Num_pg_attr_indices, idescs);
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	}
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	heap_close(attr_rel, RowExclusiveLock);
1871 1872 1873

	heap_close(rel, NoLock);
}
1874 1875

/*
1876
 * ALTER TABLE ALTER COLUMN SET NOT NULL
1877
 */
1878
void
1879 1880
AlterTableAlterColumnSetNotNull(Oid myrelid,
								bool inh, const char *colName)
1881
{
1882
	Relation	rel;
1883 1884 1885 1886 1887
	HeapTuple	tuple;
	AttrNumber	attnum;
	Relation	attr_rel;
	HeapScanDesc 	scan;
	TupleDesc	tupdesc;
1888

1889
	rel = heap_open(myrelid, AccessExclusiveLock);
1890

1891 1892
	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
1893
			 RelationGetRelationName(rel));
1894

1895 1896 1897
	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
1898
			 RelationGetRelationName(rel));
1899

1900
	if (!pg_class_ownercheck(myrelid, GetUserId()))
1901
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
1902 1903

	/*
1904
	 * Propagate to children if desired
1905
	 */
1906
	if (inh)
1907
	{
1908 1909
		List	   *child,
				   *children;
1910

1911 1912
		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);
1913

1914 1915 1916 1917 1918 1919
		/*
		 * 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)
1920
		{
1921
			Oid			childrelid = lfirsti(child);
1922

1923 1924 1925 1926 1927
			if (childrelid == myrelid)
				continue;
			AlterTableAlterColumnSetNotNull(childrelid,
											false, colName);
		}
1928 1929
	}

1930 1931
	/* -= now do the thing on this relation =- */

1932
	/*
1933
	 * get the number of the attribute
1934
	 */
1935 1936 1937 1938 1939 1940 1941
	tuple = SearchSysCache(ATTNAME,
						   ObjectIdGetDatum(myrelid),
						   PointerGetDatum(colName),
						   0, 0);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
			 RelationGetRelationName(rel), colName);
1942

1943 1944
	attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
	ReleaseSysCache(tuple);
1945

1946 1947 1948 1949
	/* Prevent them from altering a system attribute */
	if (attnum < 0)
		elog(ERROR, "ALTER TABLE: Cannot alter system attribute \"%s\"",
			 colName);
1950

1951
	/*
1952 1953
	 * Perform a scan to ensure that there are no NULL
	 * values already in the relation
1954
	 */
1955
	tupdesc = RelationGetDescr(rel);
1956

1957
	scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
1958

1959
	while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
1960 1961 1962
	{
		Datum 		d;
		bool		isnull;
1963

1964
		d = heap_getattr(tuple, attnum, tupdesc, &isnull);
1965

1966 1967 1968 1969
		if (isnull)
			elog(ERROR, "ALTER TABLE: Attribute \"%s\" contains NULL values",
				 colName);
	}
1970

1971
	heap_endscan(scan);
1972

1973 1974 1975 1976
	/*
	 * Okay, actually perform the catalog change
	 */
	attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);
1977

1978 1979 1980 1981 1982 1983 1984
	tuple = SearchSysCacheCopy(ATTNAME,
							   ObjectIdGetDatum(myrelid),
							   PointerGetDatum(colName),
							   0, 0);
	if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
		elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
			 RelationGetRelationName(rel), colName);
1985

1986
	((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = TRUE;
1987

1988
	simple_heap_update(attr_rel, &tuple->t_self, tuple);
1989

1990 1991 1992 1993
	/* keep the system catalog indices current */
	if (RelationGetForm(attr_rel)->relhasindex)
	{
		Relation	idescs[Num_pg_attr_indices];
1994

1995 1996 1997 1998
		CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, idescs);
		CatalogIndexInsert(idescs, Num_pg_attr_indices, attr_rel, tuple);
		CatalogCloseIndices(Num_pg_attr_indices, idescs);
	}
1999

2000
	heap_close(attr_rel, RowExclusiveLock);
2001

2002 2003
	heap_close(rel, NoLock);
}
2004 2005


2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
/*
 * ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
 */
void
AlterTableAlterColumnDefault(Oid myrelid,
							 bool inh, const char *colName,
							 Node *newDefault)
{
	Relation	rel;
	HeapTuple	tuple;
	AttrNumber	attnum;
2017

2018
	rel = heap_open(myrelid, AccessExclusiveLock);
2019

2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033
	/*
	 * 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));
2034

2035
	if (!pg_class_ownercheck(myrelid, GetUserId()))
2036
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
2037 2038

	/*
2039
	 * Propagate to children if desired
2040
	 */
2041
	if (inh)
2042
	{
2043 2044
		List	   *child,
				   *children;
2045

2046 2047
		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);
2048

2049 2050 2051 2052 2053 2054 2055 2056
		/*
		 * 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);
2057

2058 2059 2060 2061 2062
			if (childrelid == myrelid)
				continue;
			AlterTableAlterColumnDefault(childrelid,
										 false, colName, newDefault);
		}
2063 2064
	}

2065 2066
	/* -= now do the thing on this relation =- */

2067
	/*
2068
	 * get the number of the attribute
2069
	 */
2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080
	tuple = SearchSysCache(ATTNAME,
						   ObjectIdGetDatum(myrelid),
						   PointerGetDatum(colName),
						   0, 0);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
			 RelationGetRelationName(rel), colName);

	attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
	ReleaseSysCache(tuple);

2081 2082 2083 2084 2085 2086 2087
	/*
	 * 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);

2088
	if (newDefault)
2089
	{
2090 2091
		/* SET DEFAULT */
		RawColumnDefault *rawEnt;
2092

2093 2094 2095
		rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
		rawEnt->attnum = attnum;
		rawEnt->raw_default = newDefault;
2096

2097 2098 2099 2100 2101 2102
		/*
		 * This function is intended for CREATE TABLE, so it processes a
		 * _list_ of defaults, but we just do one.
		 */
		AddRelationRawConstraints(rel, makeList1(rawEnt), NIL);
	}
2103

2104
	heap_close(rel, NoLock);
2105 2106
}

2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122
/*
 * 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);
2123

2124 2125 2126
	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
			 RelationGetRelationName(rel));
2127

2128 2129 2130 2131 2132 2133
	/*
	 * 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));
2134

2135
	if (!pg_class_ownercheck(myrelid, GetUserId()))
2136
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
2137

2138 2139 2140 2141 2142 2143 2144 2145
	/*
	 * Check the supplied parameters before anything else
	 */
	if (*flagType == 'S')
	{
		/* STATISTICS */
		Assert(IsA(flagValue, Integer));
		newtarget = intVal(flagValue);
2146

2147 2148 2149 2150 2151 2152 2153
		/*
		 * Limit target to sane range (should we raise an error instead?)
		 */
		if (newtarget < 0)
			newtarget = 0;
		else if (newtarget > 1000)
			newtarget = 1000;
2154
	}
2155 2156 2157 2158
	else if (*flagType == 'M')
	{
		/* STORAGE */
		char        *storagemode;
2159

2160 2161
		Assert(IsA(flagValue, String));
		storagemode = strVal(flagValue);
2162

2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179
		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);
	}
2180 2181

	/*
2182
	 * Propagate to children if desired
2183
	 */
2184
	if (inh)
2185
	{
2186 2187
		List	   *child,
				   *children;
2188

2189 2190
		/* this routine is actually in the planner */
		children = find_all_inheritors(myrelid);
2191

2192 2193 2194 2195 2196 2197
		/*
		 * 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)
2198
		{
2199
			Oid			childrelid = lfirsti(child);
2200

2201 2202 2203 2204
			if (childrelid == myrelid)
				continue;
			AlterTableAlterColumnFlags(childrelid,
									   false, colName, flagValue, flagType);
2205 2206 2207
		}
	}

2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223
	/* -= now do the thing on this relation =- */

	attrelation = heap_openr(AttributeRelationName, RowExclusiveLock);

	tuple = SearchSysCacheCopy(ATTNAME,
							   ObjectIdGetDatum(myrelid),
							   PointerGetDatum(colName),
							   0, 0);
	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);
2224
	/*
2225
	 * Now change the appropriate field
2226
	 */
2227 2228 2229
	if (*flagType == 'S')
		attrtuple->attstattarget = newtarget;
	else if (*flagType == 'M')
2230
	{
2231 2232 2233 2234 2235 2236 2237 2238 2239
		/*
		 * 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));
2240 2241
	}

2242
	simple_heap_update(attrelation, &tuple->t_self, tuple);
2243

2244
	/* keep system catalog indices current */
2245
	{
2246
		Relation	irelations[Num_pg_attr_indices];
2247

2248 2249 2250
		CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, irelations);
		CatalogIndexInsert(irelations, Num_pg_attr_indices, attrelation, tuple);
		CatalogCloseIndices(Num_pg_attr_indices, irelations);
2251
	}
2252 2253 2254 2255

	heap_freetuple(tuple);
	heap_close(attrelation, NoLock);
	heap_close(rel, NoLock);	/* close rel, but keep lock! */
2256 2257
}

2258

2259
/*
2260
 * ALTER TABLE DROP COLUMN
2261
 */
2262 2263 2264
void
AlterTableDropColumn(Oid myrelid,
					 bool inh, const char *colName,
2265
					 DropBehavior behavior)
2266
{
2267
	elog(ERROR, "ALTER TABLE / DROP COLUMN is not implemented");
2268 2269 2270 2271
}


/*
2272
 * ALTER TABLE ADD CONSTRAINT
2273 2274
 */
void
2275 2276 2277 2278 2279
AlterTableAddConstraint(Oid myrelid,
						bool inh, List *newConstraints)
{
	Relation	rel;
	List	   *listptr;
2280
	int			counter = 0;
2281 2282 2283 2284 2285

	/*
	 * Grab an exclusive lock on the target table, which we will NOT
	 * release until end of transaction.
	 */
2286
	rel = heap_open(myrelid, AccessExclusiveLock);
2287

2288 2289 2290
	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
			 RelationGetRelationName(rel));
2291

2292 2293 2294 2295 2296 2297
	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
			 RelationGetRelationName(rel));

	if (!pg_class_ownercheck(myrelid, GetUserId()))
2298
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
2299 2300

	if (inh)
2301 2302 2303 2304 2305
	{
		List	   *child,
				   *children;

		/* this routine is actually in the planner */
2306
		children = find_all_inheritors(myrelid);
2307 2308 2309 2310 2311 2312 2313 2314 2315 2316

		/*
		 * 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);

2317
			if (childrelid == myrelid)
2318
				continue;
2319
			AlterTableAddConstraint(childrelid, false, newConstraints);
2320 2321 2322
		}
	}

2323 2324
	foreach(listptr, newConstraints)
	{
2325 2326 2327 2328 2329 2330
		/*
		 * 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));
2331

2332 2333 2334 2335 2336
		switch (nodeTag(newConstraint))
		{
			case T_Constraint:
				{
					Constraint *constr = (Constraint *) newConstraint;
2337

2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356
					/*
					 * 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;
2357

2358 2359 2360
								/*
								 * Assign or validate constraint name
								 */
2361
								if (constr->name)
2362 2363 2364 2365 2366 2367 2368 2369
								{
									if (ConstraintNameIsUsed(RelationGetRelid(rel),
															 RelationGetNamespace(rel),
															 constr->name))
										elog(ERROR, "constraint \"%s\" already exists for relation \"%s\"",
											 constr->name,
											 RelationGetRelationName(rel));
								}
2370
								else
2371 2372 2373
									constr->name = GenerateConstraintName(RelationGetRelid(rel),
																		  RelationGetNamespace(rel),
																		  &counter);
2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397

								/*
								 * 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.
								 */
2398
								expr = coerce_to_boolean(expr, "CHECK");
2399 2400 2401 2402 2403 2404 2405 2406 2407

								/*
								 * 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));

2408 2409 2410 2411 2412 2413 2414 2415
								/*
								 * 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");

2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436
								/*
								 * 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.
								 */
2437
								scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
2438

2439
								while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455
								{
									ExecStoreTuple(tuple, slot, InvalidBuffer, false);
									if (!ExecQual(qual, econtext, true))
									{
										successful = false;
										break;
									}
									ResetExprContext(econtext);
								}

								heap_endscan(scan);

								FreeExprContext(econtext);
								pfree(slot);

								if (!successful)
2456 2457
									elog(ERROR, "AlterTableAddConstraint: rejected due to CHECK constraint %s",
										 constr->name);
2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479

								/*
								 * 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;
2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497
					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);
2498 2499 2500 2501

					/*
					 * Grab an exclusive lock on the pk table, so that
					 * someone doesn't delete rows out from under us.
2502 2503 2504 2505
					 * (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.)
2506 2507 2508 2509 2510 2511 2512 2513
					 */
					pkrel = heap_openrv(fkconstraint->pktable,
										AccessExclusiveLock);

					/*
					 * Validity checks
					 */
					if (pkrel->rd_rel->relkind != RELKIND_RELATION)
2514 2515 2516 2517 2518 2519 2520 2521 2522
						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? */
2523 2524 2525

					if (isTempNamespace(RelationGetNamespace(pkrel)) &&
						!isTempNamespace(RelationGetNamespace(rel)))
2526
						elog(ERROR, "ALTER TABLE / ADD CONSTRAINT: Unable to reference temporary table from permanent table constraint");
2527 2528

					/*
2529 2530
					 * Check that the constraint is satisfied by existing
					 * rows (we can skip this during table creation).
2531 2532 2533 2534 2535 2536
					 *
					 * 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.
					 */
2537 2538
					if (!fkconstraint->skip_validation)
						validateForeignKeyConstraint(fkconstraint, rel, pkrel);
2539

2540 2541 2542 2543 2544
					/*
					 * Record the FK constraint in pg_constraint.
					 */
					constrOid = createForeignKeyConstraint(rel, pkrel,
														   fkconstraint);
2545

2546 2547 2548 2549
					/*
					 * Create the triggers that will enforce the constraint.
					 */
					createForeignKeyTriggers(rel, fkconstraint, constrOid);
2550

2551 2552 2553 2554
					/*
					 * Close pk table, but keep lock until we've committed.
					 */
					heap_close(pkrel, NoLock);
2555

2556 2557 2558 2559 2560 2561
					break;
				}
			default:
				elog(ERROR, "ALTER TABLE / ADD CONSTRAINT unable to determine type of constraint passed");
		}
	}
2562

2563 2564 2565
	/* Close rel, but keep lock till commit */
	heap_close(rel, NoLock);
}
2566

2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610
/*
 * 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);
2611

2612 2613 2614 2615 2616 2617 2618
		trig.tgargs[count] = fk_at->name;
		count += 2;
	}
	count = 5;
	foreach(list, fkconstraint->pk_attrs)
	{
		Ident	   *pk_at = lfirst(list);
2619

2620 2621 2622 2623
		trig.tgargs[count] = pk_at->name;
		count += 2;
	}
	trig.tgnargs = count - 1;
2624

2625
	scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
2626

2627 2628 2629 2630
	while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
	{
		FunctionCallInfoData fcinfo;
		TriggerData trigdata;
2631

2632 2633 2634 2635 2636 2637
		/*
		 * Make a call to the trigger function
		 *
		 * No parameters are passed, but we do set a context
		 */
		MemSet(&fcinfo, 0, sizeof(fcinfo));
2638

2639 2640 2641 2642 2643 2644 2645 2646 2647
		/*
		 * 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;
2648

2649 2650 2651
		fcinfo.context = (Node *) &trigdata;

		RI_FKey_check_ins(&fcinfo);
2652 2653
	}

2654 2655 2656
	heap_endscan(scan);

	pfree(trig.tgargs);
2657 2658
}

2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710
/*
 * 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);

		fkattr[i++] = get_attnum(RelationGetRelid(rel), id->name);
	}

	/* 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);

		pkattr[i++] = get_attnum(RelationGetRelid(pkrel), id->name);
	}

	/* 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,
2711
								 NULL, /* no check constraint */
2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 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
								 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 */
}
2977

2978
/*
2979
 * ALTER TABLE DROP CONSTRAINT
2980 2981
 */
void
2982 2983
AlterTableDropConstraint(Oid myrelid,
						 bool inh, const char *constrName,
2984
						 DropBehavior behavior)
2985
{
2986
	Relation	rel;
2987
	int			deleted = 0;
2988 2989

	/*
2990 2991
	 * Acquire an exclusive lock on the target relation for the duration
	 * of the operation.
2992
	 */
2993
	rel = heap_open(myrelid, AccessExclusiveLock);
2994

2995 2996 2997 2998
	/* 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));
2999

3000 3001 3002 3003 3004 3005
	if (!allowSystemTableMods
		&& IsSystemRelation(rel))
		elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
			 RelationGetRelationName(rel));

	if (!pg_class_ownercheck(myrelid, GetUserId()))
3006
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
3007 3008

	/*
3009
	 * Process child tables if requested.
3010
	 */
3011 3012 3013 3014
	if (inh)
	{
		List	   *child,
				   *children;
3015

3016 3017
		/* This routine is actually in the planner */
		children = find_all_inheritors(myrelid);
3018

3019 3020 3021 3022 3023 3024 3025 3026 3027
		/*
		 * 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;
3028

3029 3030 3031 3032 3033 3034 3035 3036
			if (childrelid == myrelid)
				continue;
			inhrel = heap_open(childrelid, AccessExclusiveLock);
			/* do NOT count child constraints in deleted. */
			RemoveRelConstraints(inhrel, constrName, behavior);
			heap_close(inhrel, NoLock);
		}
	}
3037 3038

	/*
3039
	 * Now do the thing on this relation.
3040
	 */
3041
	deleted += RemoveRelConstraints(rel, constrName, behavior);
3042

3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056
	/* 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
3057
 */
3058 3059
void
AlterTableOwner(Oid relationOid, int32 newOwnerSysId)
3060
{
3061 3062 3063 3064 3065
	Relation		target_rel;
	Relation		class_rel;
	HeapTuple		tuple;
	Relation		idescs[Num_pg_class_indices];
	Form_pg_class	tuple_class;
3066

3067
	/* Get exclusive lock till end of transaction on the target table */
3068 3069
	/* Use relation_open here so that we work on indexes... */
	target_rel = relation_open(relationOid, AccessExclusiveLock);
3070

3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082
	/* 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);
3083 3084

	/*
3085 3086
	 * Okay, this is a valid tuple: change its ownership and
	 * write to the heap.
3087
	 */
3088 3089
	tuple_class->relowner = newOwnerSysId;
	simple_heap_update(class_rel, &tuple->t_self, tuple);
3090

3091 3092 3093 3094
	/* Keep the catalog indices up to date */
	CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs);
	CatalogIndexInsert(idescs, Num_pg_class_indices, class_rel, tuple);
	CatalogCloseIndices(Num_pg_class_indices, idescs);
3095 3096

	/*
3097 3098 3099
	 * 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)
3100
	 */
3101 3102
	if (tuple_class->relkind == RELKIND_RELATION ||
		tuple_class->relkind == RELKIND_TOASTVALUE)
3103
	{
3104
		List *index_oid_list, *i;
3105

3106 3107
		/* Find all the indexes belonging to this relation */
		index_oid_list = RelationGetIndexList(target_rel);
3108

3109 3110 3111 3112 3113
		/* For each index, recursively change its ownership */
		foreach(i, index_oid_list)
		{
			AlterTableOwner(lfirsti(i), newOwnerSysId);
		}
3114

3115 3116
		freeList(index_oid_list);
	}
3117

3118 3119 3120 3121 3122 3123
	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);
3124 3125 3126
		}
	}

3127 3128
	heap_freetuple(tuple);
	heap_close(class_rel, RowExclusiveLock);
3129
	relation_close(target_rel, NoLock);
3130 3131
}

3132 3133
static void
CheckTupleType(Form_pg_class tuple_class)
3134
{
3135
	switch (tuple_class->relkind)
3136
	{
3137 3138 3139 3140 3141 3142 3143 3144 3145 3146
		case RELKIND_RELATION:
		case RELKIND_INDEX:
		case RELKIND_VIEW:
		case RELKIND_SEQUENCE:
		case RELKIND_TOASTVALUE:
			/* ok to change owner */
			break;
		default:
			elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table, TOAST table, index, view, or sequence",
				 NameStr(tuple_class->relname));
3147 3148 3149 3150
	}
}

/*
3151
 * ALTER TABLE CREATE TOAST TABLE
3152
 */
3153 3154
void
AlterTableCreateToastTable(Oid relOid, bool silent)
3155
{
3156 3157 3158 3159
	Relation	rel;
	HeapTuple	reltup;
	HeapTupleData classtuple;
	TupleDesc	tupdesc;
3160
	bool		shared_relation;
3161 3162 3163 3164 3165 3166 3167 3168 3169
	Relation	class_rel;
	Buffer		buffer;
	Relation	ridescs[Num_pg_class_indices];
	Oid			toast_relid;
	Oid			toast_idxid;
	char		toast_relname[NAMEDATALEN];
	char		toast_idxname[NAMEDATALEN];
	IndexInfo  *indexInfo;
	Oid			classObjectId[2];
3170 3171
	ObjectAddress baseobject,
				toastobject;
3172

3173 3174 3175 3176 3177
	/*
	 * Grab an exclusive lock on the target table, which we will NOT
	 * release until end of transaction.
	 */
	rel = heap_open(relOid, AccessExclusiveLock);
3178

3179
	/* Check permissions */
3180 3181 3182
	if (rel->rd_rel->relkind != RELKIND_RELATION)
		elog(ERROR, "ALTER TABLE: relation \"%s\" is not a table",
			 RelationGetRelationName(rel));
3183

3184
	if (!pg_class_ownercheck(relOid, GetUserId()))
3185
		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
3186

3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199
	/*
	 * 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");

3200 3201 3202 3203
	/*
	 * lock the pg_class tuple for update (is that really needed?)
	 */
	class_rel = heap_openr(RelationRelationName, RowExclusiveLock);
3204

3205 3206 3207 3208 3209 3210 3211 3212 3213
	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);

3214 3215
	switch (heap_mark4update(class_rel, &classtuple, &buffer,
							 GetCurrentCommandId()))
3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231
	{
		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)
3232
		{
3233 3234 3235 3236
			heap_close(rel, NoLock);
			heap_close(class_rel, NoLock);
			heap_freetuple(reltup);
			return;
3237 3238
		}

3239 3240 3241
		elog(ERROR, "ALTER TABLE: relation \"%s\" already has a toast table",
			 RelationGetRelationName(rel));
	}
3242

3243 3244 3245 3246 3247 3248
	/*
	 * Check to see whether the table actually needs a TOAST table.
	 */
	if (!needs_toast_table(rel))
	{
		if (silent)
3249
		{
3250 3251 3252 3253
			heap_close(rel, NoLock);
			heap_close(class_rel, NoLock);
			heap_freetuple(reltup);
			return;
3254 3255
		}

3256 3257 3258
		elog(ERROR, "ALTER TABLE: relation \"%s\" does not need a toast table",
			 RelationGetRelationName(rel));
	}
3259

3260 3261 3262 3263 3264
	/*
	 * Create the toast table and its index
	 */
	sprintf(toast_relname, "pg_toast_%u", relOid);
	sprintf(toast_idxname, "pg_toast_%u_index", relOid);
3265

3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279
	/* this is pretty painful...  need a tuple descriptor */
	tupdesc = CreateTemplateTupleDesc(3);
	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);
3280

3281 3282 3283 3284 3285 3286 3287 3288
	/*
	 * 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';
3289

3290 3291 3292 3293 3294 3295 3296 3297 3298 3299
	/*
	 * 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,
3300
										   shared_relation,
3301 3302
										   false,
										   true);
3303

3304 3305
	/* make the toast relation visible, else index creation will fail */
	CommandCounterIncrement();
3306

3307 3308 3309 3310 3311 3312 3313 3314 3315 3316
	/*
	 * 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.
	 */
3317

3318 3319 3320 3321 3322 3323 3324 3325
	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;
3326

3327 3328
	classObjectId[0] = OID_BTREE_OPS_OID;
	classObjectId[1] = INT4_BTREE_OPS_OID;
3329

3330 3331
	toast_idxid = index_create(toast_relid, toast_idxname, indexInfo,
							   BTREE_AM_OID, classObjectId,
3332
							   true, false, true);
3333

3334 3335 3336 3337 3338 3339
	/*
	 * 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);
3340 3341

	/*
3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355
	 * Store the toast table's OID in the parent relation's tuple
	 */
	((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;
	simple_heap_update(class_rel, &reltup->t_self, reltup);

	/*
	 * Keep catalog indices current
	 */
	CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, ridescs);
	CatalogIndexInsert(ridescs, Num_pg_class_indices, class_rel, reltup);
	CatalogCloseIndices(Num_pg_class_indices, ridescs);

	heap_freetuple(reltup);

3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368
	/*
	 * 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);

3369 3370
	/*
	 * Close relations and make changes visible
3371
	 */
3372 3373 3374
	heap_close(class_rel, NoLock);
	heap_close(rel, NoLock);

3375
	CommandCounterIncrement();
3376
}
3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427

/*
 * 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);
}