pg_operator.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

		restOid = LookupFuncName(restrictionName, 4, typeId, false);
	}
	else
		restOid = InvalidOid;

	/*
	 * find join estimator
	 */
	if (joinName)
	{
		typeId[0] = INTERNALOID;	/* Query */
		typeId[1] = OIDOID;		/* operator OID */
		typeId[2] = INTERNALOID;	/* args list */
		typeId[3] = INT2OID;	/* jointype */

		joinOid = LookupFuncName(joinName, 4, typeId, false);
	}
	else
		joinOid = InvalidOid;

	/*
	 * set up values in the operator tuple
	 */

	for (i = 0; i < Natts_pg_operator; ++i)
	{
		values[i] = (Datum) NULL;
		replaces[i] = 'r';
		nulls[i] = ' ';
	}

	i = 0;
	namestrcpy(&oname, operatorName);
	values[i++] = NameGetDatum(&oname); /* oprname */
	values[i++] = ObjectIdGetDatum(operatorNamespace);	/* oprnamespace */
	values[i++] = ObjectIdGetDatum(GetUserId());		/* oprowner */
	values[i++] = CharGetDatum(leftTypeId ? (rightTypeId ? 'b' : 'r') : 'l');	/* oprkind */
	values[i++] = BoolGetDatum(canHash);		/* oprcanhash */
	values[i++] = ObjectIdGetDatum(leftTypeId); /* oprleft */
	values[i++] = ObjectIdGetDatum(rightTypeId);		/* oprright */
	values[i++] = ObjectIdGetDatum(operResultType);		/* oprresult */

	/*
	 * Set up the other operators.	If they do not currently exist, create
	 * shells in order to get ObjectId's.
	 */

	if (commutatorName)
	{
		/* commutator has reversed arg types */
		commutatorId = get_other_operator(commutatorName,
										  rightTypeId, leftTypeId,
										  operatorName, operatorNamespace,
										  leftTypeId, rightTypeId,
										  true);

		/*
		 * self-linkage to this operator; will fix below. Note that only
		 * self-linkage for commutation makes sense.
		 */
		if (!OidIsValid(commutatorId))
			selfCommutator = true;
	}
	else
		commutatorId = InvalidOid;
	values[i++] = ObjectIdGetDatum(commutatorId);		/* oprcom */

	if (negatorName)
	{
		/* negator has same arg types */
		negatorId = get_other_operator(negatorName,
									   leftTypeId, rightTypeId,
									   operatorName, operatorNamespace,
									   leftTypeId, rightTypeId,
									   false);
	}
	else
		negatorId = InvalidOid;
	values[i++] = ObjectIdGetDatum(negatorId);	/* oprnegate */

	if (leftSortName)
	{
		/* left sort op takes left-side data type */
		leftSortId = get_other_operator(leftSortName,
										leftTypeId, leftTypeId,
										operatorName, operatorNamespace,
										leftTypeId, rightTypeId,
										false);
	}
	else
		leftSortId = InvalidOid;
	values[i++] = ObjectIdGetDatum(leftSortId); /* oprlsortop */

	if (rightSortName)
	{
		/* right sort op takes right-side data type */
		rightSortId = get_other_operator(rightSortName,
										 rightTypeId, rightTypeId,
										 operatorName, operatorNamespace,
										 leftTypeId, rightTypeId,
										 false);
	}
	else
		rightSortId = InvalidOid;
	values[i++] = ObjectIdGetDatum(rightSortId);		/* oprrsortop */

	if (ltCompareName)
	{
		/* comparator has same arg types */
		ltCompareId = get_other_operator(ltCompareName,
										 leftTypeId, rightTypeId,
										 operatorName, operatorNamespace,
										 leftTypeId, rightTypeId,
										 false);
	}
	else
		ltCompareId = InvalidOid;
	values[i++] = ObjectIdGetDatum(ltCompareId);		/* oprltcmpop */

	if (gtCompareName)
	{
		/* comparator has same arg types */
		gtCompareId = get_other_operator(gtCompareName,
										 leftTypeId, rightTypeId,
										 operatorName, operatorNamespace,
										 leftTypeId, rightTypeId,
										 false);
	}
	else
		gtCompareId = InvalidOid;
	values[i++] = ObjectIdGetDatum(gtCompareId);		/* oprgtcmpop */

	values[i++] = ObjectIdGetDatum(procOid);	/* oprcode */
	values[i++] = ObjectIdGetDatum(restOid);	/* oprrest */
	values[i++] = ObjectIdGetDatum(joinOid);	/* oprjoin */

	pg_operator_desc = heap_open(OperatorRelationId, RowExclusiveLock);

	/*
	 * If we are adding to an operator shell, update; else insert
	 */
	if (operatorObjectId)
	{
		tup = SearchSysCacheCopy(OPEROID,
								 ObjectIdGetDatum(operatorObjectId),
								 0, 0, 0);
		if (!HeapTupleIsValid(tup))
			elog(ERROR, "cache lookup failed for operator %u",
				 operatorObjectId);

		tup = heap_modifytuple(tup,
							   RelationGetDescr(pg_operator_desc),
							   values,
							   nulls,
							   replaces);

		simple_heap_update(pg_operator_desc, &tup->t_self, tup);
	}
	else
	{
		tupDesc = pg_operator_desc->rd_att;
		tup = heap_formtuple(tupDesc, values, nulls);

		operatorObjectId = simple_heap_insert(pg_operator_desc, tup);
	}

	/* Must update the indexes in either case */
	CatalogUpdateIndexes(pg_operator_desc, tup);

	/* Add dependencies for the entry */
	makeOperatorDependencies(tup);

	heap_close(pg_operator_desc, RowExclusiveLock);

	/*
	 * If a commutator and/or negator link is provided, update the other
	 * operator(s) to point at this one, if they don't already have a link.
	 * This supports an alternate style of operator definition wherein the
	 * user first defines one operator without giving negator or commutator,
	 * then defines the other operator of the pair with the proper commutator
	 * or negator attribute.  That style doesn't require creation of a shell,
	 * and it's the only style that worked right before Postgres version 6.5.
	 * This code also takes care of the situation where the new operator is
	 * its own commutator.
	 */
	if (selfCommutator)
		commutatorId = operatorObjectId;

	if (OidIsValid(commutatorId) || OidIsValid(negatorId))
		OperatorUpd(operatorObjectId, commutatorId, negatorId);
}

/*
 * Try to lookup another operator (commutator, etc)
 *
 * If not found, check to see if it is exactly the operator we are trying
 * to define; if so, return InvalidOid.  (Note that this case is only
 * sensible for a commutator, so we error out otherwise.)  If it is not
 * the same operator, create a shell operator.
 */
static Oid
get_other_operator(List *otherOp, Oid otherLeftTypeId, Oid otherRightTypeId,
				   const char *operatorName, Oid operatorNamespace,
				   Oid leftTypeId, Oid rightTypeId, bool isCommutator)
{
	Oid			other_oid;
	bool		otherDefined;
	char	   *otherName;
	Oid			otherNamespace;
	AclResult	aclresult;

	other_oid = OperatorLookup(otherOp,
							   otherLeftTypeId,
							   otherRightTypeId,
							   &otherDefined);

	if (OidIsValid(other_oid))
	{
		/* other op already in catalogs */
		return other_oid;
	}

	otherNamespace = QualifiedNameGetCreationNamespace(otherOp,
													   &otherName);

	if (strcmp(otherName, operatorName) == 0 &&
		otherNamespace == operatorNamespace &&
		otherLeftTypeId == leftTypeId &&
		otherRightTypeId == rightTypeId)
	{
		/*
		 * self-linkage to this operator; caller will fix later. Note that
		 * only self-linkage for commutation makes sense.
		 */
		if (!isCommutator)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
			 errmsg("operator cannot be its own negator or sort operator")));
		return InvalidOid;
	}

	/* not in catalogs, different from operator, so make shell */

	aclresult = pg_namespace_aclcheck(otherNamespace, GetUserId(),
									  ACL_CREATE);
	if (aclresult != ACLCHECK_OK)
		aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
					   get_namespace_name(otherNamespace));

	other_oid = OperatorShellMake(otherName,
								  otherNamespace,
								  otherLeftTypeId,
								  otherRightTypeId);
	return other_oid;
}

/*
 * OperatorUpd
 *
 *	For a given operator, look up its negator and commutator operators.
 *	If they are defined, but their negator and commutator fields
 *	(respectively) are empty, then use the new operator for neg or comm.
 *	This solves a problem for users who need to insert two new operators
 *	which are the negator or commutator of each other.
 */
static void
OperatorUpd(Oid baseId, Oid commId, Oid negId)
{
	int			i;
	Relation	pg_operator_desc;
	HeapTuple	tup;
	char		nulls[Natts_pg_operator];
	char		replaces[Natts_pg_operator];
	Datum		values[Natts_pg_operator];

	for (i = 0; i < Natts_pg_operator; ++i)
	{
		values[i] = (Datum) 0;
		replaces[i] = ' ';
		nulls[i] = ' ';
	}

	/*
	 * check and update the commutator & negator, if necessary
	 *
	 * First make sure we can see them...
	 */
	CommandCounterIncrement();

	pg_operator_desc = heap_open(OperatorRelationId, RowExclusiveLock);

	tup = SearchSysCacheCopy(OPEROID,
							 ObjectIdGetDatum(commId),
							 0, 0, 0);

	/*
	 * if the commutator and negator are the same operator, do one update. XXX
	 * this is probably useless code --- I doubt it ever makes sense for
	 * commutator and negator to be the same thing...
	 */
	if (commId == negId)
	{
		if (HeapTupleIsValid(tup))
		{
			Form_pg_operator t = (Form_pg_operator) GETSTRUCT(tup);

			if (!OidIsValid(t->oprcom) || !OidIsValid(t->oprnegate))
			{
				if (!OidIsValid(t->oprnegate))
				{
					values[Anum_pg_operator_oprnegate - 1] = ObjectIdGetDatum(baseId);
					replaces[Anum_pg_operator_oprnegate - 1] = 'r';
				}

				if (!OidIsValid(t->oprcom))
				{
					values[Anum_pg_operator_oprcom - 1] = ObjectIdGetDatum(baseId);
					replaces[Anum_pg_operator_oprcom - 1] = 'r';
				}

				tup = heap_modifytuple(tup,
									   RelationGetDescr(pg_operator_desc),
									   values,
									   nulls,
									   replaces);

				simple_heap_update(pg_operator_desc, &tup->t_self, tup);

				CatalogUpdateIndexes(pg_operator_desc, tup);
			}
		}

		heap_close(pg_operator_desc, RowExclusiveLock);

		return;
	}

	/* if commutator and negator are different, do two updates */

	if (HeapTupleIsValid(tup) &&
		!(OidIsValid(((Form_pg_operator) GETSTRUCT(tup))->oprcom)))
	{
		values[Anum_pg_operator_oprcom - 1] = ObjectIdGetDatum(baseId);
		replaces[Anum_pg_operator_oprcom - 1] = 'r';

		tup = heap_modifytuple(tup,
							   RelationGetDescr(pg_operator_desc),
							   values,
							   nulls,
							   replaces);

		simple_heap_update(pg_operator_desc, &tup->t_self, tup);

		CatalogUpdateIndexes(pg_operator_desc, tup);

		values[Anum_pg_operator_oprcom - 1] = (Datum) NULL;
		replaces[Anum_pg_operator_oprcom - 1] = ' ';
	}

	/* check and update the negator, if necessary */

	tup = SearchSysCacheCopy(OPEROID,
							 ObjectIdGetDatum(negId),
							 0, 0, 0);

	if (HeapTupleIsValid(tup) &&
		!(OidIsValid(((Form_pg_operator) GETSTRUCT(tup))->oprnegate)))
	{
		values[Anum_pg_operator_oprnegate - 1] = ObjectIdGetDatum(baseId);
		replaces[Anum_pg_operator_oprnegate - 1] = 'r';

		tup = heap_modifytuple(tup,
							   RelationGetDescr(pg_operator_desc),
							   values,
							   nulls,
							   replaces);

		simple_heap_update(pg_operator_desc, &tup->t_self, tup);

		CatalogUpdateIndexes(pg_operator_desc, tup);
	}

	heap_close(pg_operator_desc, RowExclusiveLock);
}

/*
 * Create dependencies for a new operator (either a freshly inserted
 * complete operator, a new shell operator, or a just-updated shell).
 *
 * NB: the OidIsValid tests in this routine are necessary, in case
 * the given operator is a shell.
 */
static void
makeOperatorDependencies(HeapTuple tuple)
{
	Form_pg_operator oper = (Form_pg_operator) GETSTRUCT(tuple);
	ObjectAddress myself,
				referenced;

	myself.classId = OperatorRelationId;
	myself.objectId = HeapTupleGetOid(tuple);
	myself.objectSubId = 0;

	/* In case we are updating a shell, delete any existing entries */
	deleteDependencyRecordsFor(myself.classId, myself.objectId);
	deleteSharedDependencyRecordsFor(myself.classId, myself.objectId);

	/* Dependency on namespace */
	if (OidIsValid(oper->oprnamespace))
	{
		referenced.classId = NamespaceRelationId;
		referenced.objectId = oper->oprnamespace;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/* Dependency on left type */
	if (OidIsValid(oper->oprleft))
	{
		referenced.classId = TypeRelationId;
		referenced.objectId = oper->oprleft;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/* Dependency on right type */
	if (OidIsValid(oper->oprright))
	{
		referenced.classId = TypeRelationId;
		referenced.objectId = oper->oprright;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/* Dependency on result type */
	if (OidIsValid(oper->oprresult))
	{
		referenced.classId = TypeRelationId;
		referenced.objectId = oper->oprresult;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/*
	 * NOTE: we do not consider the operator to depend on the associated
	 * operators oprcom, oprnegate, oprlsortop, oprrsortop, oprltcmpop,
	 * oprgtcmpop.	We would not want to delete this operator if those go
	 * away, but only reset the link fields; which is not a function that the
	 * dependency code can presently handle.  (Something could perhaps be done
	 * with objectSubId though.)  For now, it's okay to let those links dangle
	 * if a referenced operator is removed.
	 */

	/* Dependency on implementation function */
	if (OidIsValid(oper->oprcode))
	{
		referenced.classId = ProcedureRelationId;
		referenced.objectId = oper->oprcode;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/* Dependency on restriction selectivity function */
	if (OidIsValid(oper->oprrest))
	{
		referenced.classId = ProcedureRelationId;
		referenced.objectId = oper->oprrest;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/* Dependency on join selectivity function */
	if (OidIsValid(oper->oprjoin))
	{
		referenced.classId = ProcedureRelationId;
		referenced.objectId = oper->oprjoin;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/* Dependency on owner */
	recordDependencyOnOwner(OperatorRelationId, HeapTupleGetOid(tuple),
							oper->oprowner);
}