index.c

关系型数据库 Postgresql 6.5.2

	 * ----------------
	 */

	indexRelation->rd_rel->relowner = GetUserId();

	indexRelation->rd_rel->relam = amoid;
	indexRelation->rd_rel->reltuples = 1;		/* XXX */
	indexRelation->rd_rel->relkind = RELKIND_INDEX;
}

/* ----------------------------------------------------------------
 *		UpdateRelationRelation
 * ----------------------------------------------------------------
 */
static Oid
UpdateRelationRelation(Relation indexRelation, char *temp_relname)
{
	Relation	pg_class;
	HeapTuple	tuple;
	Oid			tupleOid;
	Relation	idescs[Num_pg_class_indices];

	pg_class = heap_openr(RelationRelationName);

	/* XXX Natts_pg_class_fixed is a hack - see pg_class.h */
	tuple = heap_addheader(Natts_pg_class_fixed,
						   sizeof(*indexRelation->rd_rel),
						   (char *) indexRelation->rd_rel);

	/* ----------------
	 *	the new tuple must have the same oid as the relcache entry for the
	 *	index.	sure would be embarassing to do this sort of thing in polite
	 *	company.
	 * ----------------
	 */
	tuple->t_data->t_oid = RelationGetRelid(indexRelation);
	heap_insert(pg_class, tuple);

	if (temp_relname)
		create_temp_relation(temp_relname, tuple);

	/*
	 * During normal processing, we need to make sure that the system
	 * catalog indices are correct.  Bootstrap (initdb) time doesn't
	 * require this, because we make sure that the indices are correct
	 * just before exiting.
	 */

	if (!IsBootstrapProcessingMode())
	{
		CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs);
		CatalogIndexInsert(idescs, Num_pg_class_indices, pg_class, tuple);
		CatalogCloseIndices(Num_pg_class_indices, idescs);
	}

	tupleOid = tuple->t_data->t_oid;
	pfree(tuple);
	heap_close(pg_class);

	return tupleOid;
}

/* ----------------------------------------------------------------
 *		InitializeAttributeOids
 * ----------------------------------------------------------------
 */
static void
InitializeAttributeOids(Relation indexRelation,
						int numatts,
						Oid indexoid)
{
	TupleDesc	tupleDescriptor;
	int			i;

	tupleDescriptor = RelationGetDescr(indexRelation);

	for (i = 0; i < numatts; i += 1)
		tupleDescriptor->attrs[i]->attrelid = indexoid;
}

/* ----------------------------------------------------------------
 *		AppendAttributeTuples
 *
 *		XXX For now, only change the ATTNUM attribute value
 * ----------------------------------------------------------------
 */
static void
AppendAttributeTuples(Relation indexRelation, int numatts)
{
	Relation	pg_attribute;
	HeapTuple	init_tuple,
				cur_tuple = NULL,
				new_tuple;
	bool		hasind;
	Relation	idescs[Num_pg_attr_indices];

	Datum		value[Natts_pg_attribute];
	char		nullv[Natts_pg_attribute];
	char		replace[Natts_pg_attribute];

	TupleDesc	indexTupDesc;
	int			i;

	/* ----------------
	 *	open the attribute relation
	 *	XXX ADD INDEXING
	 * ----------------
	 */
	pg_attribute = heap_openr(AttributeRelationName);

	/* ----------------
	 *	initialize *null, *replace and *value
	 * ----------------
	 */
	MemSet(nullv, ' ', Natts_pg_attribute);
	MemSet(replace, ' ', Natts_pg_attribute);

	/* ----------------
	 *	create the first attribute tuple.
	 *	XXX For now, only change the ATTNUM attribute value
	 * ----------------
	 */
	replace[Anum_pg_attribute_attnum - 1] = 'r';
	replace[Anum_pg_attribute_attcacheoff - 1] = 'r';

	value[Anum_pg_attribute_attnum - 1] = Int16GetDatum(1);
	value[Anum_pg_attribute_attcacheoff - 1] = Int32GetDatum(-1);

	init_tuple = heap_addheader(Natts_pg_attribute,
								ATTRIBUTE_TUPLE_SIZE,
							 (char *) (indexRelation->rd_att->attrs[0]));

	hasind = false;
	if (!IsBootstrapProcessingMode() && pg_attribute->rd_rel->relhasindex)
	{
		hasind = true;
		CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, idescs);
	}

	/* ----------------
	 *	insert the first attribute tuple.
	 * ----------------
	 */
	cur_tuple = heap_modifytuple(init_tuple,
								 pg_attribute,
								 value,
								 nullv,
								 replace);
	pfree(init_tuple);

	heap_insert(pg_attribute, cur_tuple);
	if (hasind)
		CatalogIndexInsert(idescs, Num_pg_attr_indices, pg_attribute, cur_tuple);

	/* ----------------
	 *	now we use the information in the index cur_tuple
	 *	descriptor to form the remaining attribute tuples.
	 * ----------------
	 */
	indexTupDesc = RelationGetDescr(indexRelation);

	for (i = 1; i < numatts; i += 1)
	{
		/* ----------------
		 *	process the remaining attributes...
		 * ----------------
		 */
		memmove(GETSTRUCT(cur_tuple),
				(char *) indexTupDesc->attrs[i],
				ATTRIBUTE_TUPLE_SIZE);

		value[Anum_pg_attribute_attnum - 1] = Int16GetDatum(i + 1);

		new_tuple = heap_modifytuple(cur_tuple,
									 pg_attribute,
									 value,
									 nullv,
									 replace);
		pfree(cur_tuple);

		heap_insert(pg_attribute, new_tuple);
		if (hasind)
			CatalogIndexInsert(idescs, Num_pg_attr_indices, pg_attribute, new_tuple);

		/* ----------------
		 *	ModifyHeapTuple returns a new copy of a cur_tuple
		 *	so we free the original and use the copy..
		 * ----------------
		 */
		cur_tuple = new_tuple;
	}

	if (cur_tuple)
		pfree(cur_tuple);
	heap_close(pg_attribute);
	if (hasind)
		CatalogCloseIndices(Num_pg_attr_indices, idescs);

}

/* ----------------------------------------------------------------
 *		UpdateIndexRelation
 * ----------------------------------------------------------------
 */
static void
UpdateIndexRelation(Oid indexoid,
					Oid heapoid,
					FuncIndexInfo *funcInfo,
					int natts,
					AttrNumber *attNums,
					Oid *classOids,
					Node *predicate,
					List *attributeList,
					bool islossy,
					bool unique,
					bool primary)
{
	Form_pg_index indexForm;
	IndexElem  *IndexKey;
	char	   *predString;
	text	   *predText;
	int			predLen,
				itupLen;
	Relation	pg_index;
	HeapTuple	tuple;
	int			i;

	/* ----------------
	 *	allocate an Form_pg_index big enough to hold the
	 *	index-predicate (if any) in string form
	 * ----------------
	 */
	if (predicate != NULL)
	{
		predString = nodeToString(predicate);
		predText = (text *) fmgr(F_TEXTIN, predString);
		pfree(predString);
	}
	else
		predText = (text *) fmgr(F_TEXTIN, "");

	predLen = VARSIZE(predText);
	itupLen = predLen + sizeof(FormData_pg_index);
	indexForm = (Form_pg_index) palloc(itupLen);
	memset(indexForm, 0, sizeof(FormData_pg_index));

	memmove((char *) &indexForm->indpred, (char *) predText, predLen);

	/* ----------------
	 *	store the oid information into the index tuple form
	 * ----------------
	 */
	indexForm->indrelid = heapoid;
	indexForm->indexrelid = indexoid;
	indexForm->indproc = (PointerIsValid(funcInfo)) ?
		FIgetProcOid(funcInfo) : InvalidOid;
	indexForm->indislossy = islossy;
	indexForm->indisprimary = primary;
	indexForm->indisunique = unique;

	indexForm->indhaskeytype = 0;
	while (attributeList != NIL)
	{
		IndexKey = (IndexElem *) lfirst(attributeList);
		if (IndexKey->typename != NULL)
		{
			indexForm->indhaskeytype = 1;
			break;
		}
		attributeList = lnext(attributeList);
	}

	MemSet((char *) &indexForm->indkey[0], 0, sizeof indexForm->indkey);
	MemSet((char *) &indexForm->indclass[0], 0, sizeof indexForm->indclass);

	/* ----------------
	 *	copy index key and op class information
	 * ----------------
	 */
	for (i = 0; i < natts; i += 1)
	{
		indexForm->indkey[i] = attNums[i];
		indexForm->indclass[i] = classOids[i];
	}

	/*
	 * If we have a functional index, add all attribute arguments
	 */
	if (PointerIsValid(funcInfo))
	{
		for (i = 1; i < FIgetnArgs(funcInfo); i++)
			indexForm->indkey[i] = attNums[i];
	}

	indexForm->indisclustered = '\0';	/* XXX constant */

	/* ----------------
	 *	open the system catalog index relation
	 * ----------------
	 */
	pg_index = heap_openr(IndexRelationName);

	/* ----------------
	 *	form a tuple to insert into pg_index
	 * ----------------
	 */
	tuple = heap_addheader(Natts_pg_index,
						   itupLen,
						   (char *) indexForm);

	/* ----------------
	 *	insert the tuple into the pg_index
	 *	XXX ADD INDEX TUPLES TOO
	 * ----------------
	 */
	heap_insert(pg_index, tuple);

	/* ----------------
	 *	close the relation and free the tuple
	 * ----------------
	 */
	heap_close(pg_index);
	pfree(predText);
	pfree(indexForm);
	pfree(tuple);
}

/* ----------------------------------------------------------------
 *		UpdateIndexPredicate
 * ----------------------------------------------------------------
 */
void
UpdateIndexPredicate(Oid indexoid, Node *oldPred, Node *predicate)
{
	Node	   *newPred;
	char	   *predString;
	text	   *predText;
	Relation	pg_index;
	HeapTuple	tuple;
	HeapTuple	newtup;
	int			i;
	Datum		values[Natts_pg_index];
	char		nulls[Natts_pg_index];
	char		replace[Natts_pg_index];

	/*
	 * Construct newPred as a CNF expression equivalent to the OR of the
	 * original partial-index predicate ("oldPred") and the extension
	 * predicate ("predicate").
	 *
	 * This should really try to process the result to change things like
	 * "a>2 OR a>1" to simply "a>1", but for now all it does is make sure
	 * that if the extension predicate is NULL (i.e., it is being extended
	 * to be a complete index), then newPred will be NULL - in effect,
	 * changing "a>2 OR TRUE" to "TRUE". --Nels, Jan '93
	 */
	newPred = NULL;
	if (predicate != NULL)
	{
		newPred = (Node *) make_orclause(lcons(make_andclause((List *) predicate),
								  lcons(make_andclause((List *) oldPred),
										NIL)));
		newPred = (Node *) cnfify((Expr *) newPred, true);
	}

	/* translate the index-predicate to string form */
	if (newPred != NULL)
	{
		predString = nodeToString(newPred);
		predText = (text *) fmgr(F_TEXTIN, predString);
		pfree(predString);
	}
	else
		predText = (text *) fmgr(F_TEXTIN, "");

	/* open the index system catalog relation */
	pg_index = heap_openr(IndexRelationName);

	tuple = SearchSysCacheTuple(INDEXRELID,
								ObjectIdGetDatum(indexoid),
								0, 0, 0);
	Assert(HeapTupleIsValid(tuple));

	for (i = 0; i < Natts_pg_index; i++)
	{
		nulls[i] = heap_attisnull(tuple, i + 1) ? 'n' : ' ';
		replace[i] = ' ';
		values[i] = (Datum) NULL;
	}

	replace[Anum_pg_index_indpred - 1] = 'r';
	values[Anum_pg_index_indpred - 1] = (Datum) predText;

	newtup = heap_modifytuple(tuple, pg_index, values, nulls, replace);

	heap_replace(pg_index, &newtup->t_self, newtup, NULL);

	pfree(newtup);
	heap_close(pg_index);
	pfree(predText);
}

/* ----------------------------------------------------------------
 *		InitIndexStrategy
 * ----------------------------------------------------------------
 */
void
InitIndexStrategy(int numatts,
				  Relation indexRelation,
				  Oid accessMethodObjectId)
{
	IndexStrategy strategy;
	RegProcedure *support;
	uint16		amstrategies;
	uint16		amsupport;
	Oid			attrelid;
	Size		strsize;
	extern GlobalMemory CacheCxt;

	/* ----------------
	 *	get information from the index relation descriptor
	 * ----------------
	 */
	attrelid = indexRelation->rd_att->attrs[0]->attrelid;
	amstrategies = indexRelation->rd_am->amstrategies;
	amsupport = indexRelation->rd_am->amsupport;

	/* ----------------
	 *	get the size of the strategy
	 * ----------------
	 */
	strsize = AttributeNumberGetIndexStrategySize(numatts, amstrategies);

	/* ----------------
	 *	allocate the new index strategy structure