opclasscmds.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/*-------------------------------------------------------------------------
 *
 * opclasscmds.c
 *
 *	  Routines for opclass manipulation commands
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/backend/commands/opclasscmds.c,v 1.38 2005/10/15 02:49:15 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/genam.h"
#include "access/heapam.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_am.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "miscadmin.h"
#include "parser/parse_func.h"
#include "parser/parse_oper.h"
#include "parser/parse_type.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"


/*
 * We use lists of this struct type to keep track of both operators and
 * procedures during DefineOpClass.
 */
typedef struct
{
	Oid			object;			/* operator or support proc's OID */
	int			number;			/* strategy or support proc number */
	Oid			subtype;		/* subtype */
	bool		recheck;		/* oper recheck flag (unused for proc) */
} OpClassMember;


static Oid	assignOperSubtype(Oid amoid, Oid typeoid, Oid operOid);
static Oid	assignProcSubtype(Oid amoid, Oid typeoid, Oid procOid);
static void addClassMember(List **list, OpClassMember *member, bool isProc);
static void storeOperators(Oid opclassoid, List *operators);
static void storeProcedures(Oid opclassoid, List *procedures);


/*
 * DefineOpClass
 *		Define a new index operator class.
 */
void
DefineOpClass(CreateOpClassStmt *stmt)
{
	char	   *opcname;		/* name of opclass we're creating */
	Oid			amoid,			/* our AM's oid */
				typeoid,		/* indexable datatype oid */
				storageoid,		/* storage datatype oid, if any */
				namespaceoid,	/* namespace to create opclass in */
				opclassoid;		/* oid of opclass we create */
	int			numOperators,	/* amstrategies value */
				numProcs;		/* amsupport value */
	List	   *operators;		/* OpClassMember list for operators */
	List	   *procedures;		/* OpClassMember list for support procs */
	ListCell   *l;
	Relation	rel;
	HeapTuple	tup;
	Datum		values[Natts_pg_opclass];
	char		nulls[Natts_pg_opclass];
	AclResult	aclresult;
	NameData	opcName;
	int			i;
	ObjectAddress myself,
				referenced;

	/* Convert list of names to a name and namespace */
	namespaceoid = QualifiedNameGetCreationNamespace(stmt->opclassname,
													 &opcname);

	/* Check we have creation rights in target namespace */
	aclresult = pg_namespace_aclcheck(namespaceoid, GetUserId(), ACL_CREATE);
	if (aclresult != ACLCHECK_OK)
		aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
					   get_namespace_name(namespaceoid));

	/* Get necessary info about access method */
	tup = SearchSysCache(AMNAME,
						 CStringGetDatum(stmt->amname),
						 0, 0, 0);
	if (!HeapTupleIsValid(tup))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("access method \"%s\" does not exist",
						stmt->amname)));

	amoid = HeapTupleGetOid(tup);
	numOperators = ((Form_pg_am) GETSTRUCT(tup))->amstrategies;
	numProcs = ((Form_pg_am) GETSTRUCT(tup))->amsupport;

	/* XXX Should we make any privilege check against the AM? */

	ReleaseSysCache(tup);

	/*
	 * Currently, we require superuser privileges to create an opclass. This
	 * seems necessary because we have no way to validate that the offered set
	 * of operators and functions are consistent with the AM's expectations.
	 * It would be nice to provide such a check someday, if it can be done
	 * without solving the halting problem :-(
	 */
	if (!superuser())
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("must be superuser to create an operator class")));

	/* Look up the datatype */
	typeoid = typenameTypeId(stmt->datatype);

#ifdef NOT_USED
	/* XXX this is unnecessary given the superuser check above */
	/* Check we have ownership of the datatype */
	if (!pg_type_ownercheck(typeoid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TYPE,
					   format_type_be(typeoid));
#endif

	operators = NIL;
	procedures = NIL;

	/* Storage datatype is optional */
	storageoid = InvalidOid;

	/*
	 * Scan the "items" list to obtain additional info.
	 */
	foreach(l, stmt->items)
	{
		CreateOpClassItem *item = lfirst(l);
		Oid			operOid;
		Oid			funcOid;
		OpClassMember *member;
		AclResult	aclresult;

		Assert(IsA(item, CreateOpClassItem));
		switch (item->itemtype)
		{
			case OPCLASS_ITEM_OPERATOR:
				if (item->number <= 0 || item->number > numOperators)
					ereport(ERROR,
							(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
							 errmsg("invalid operator number %d,"
									" must be between 1 and %d",
									item->number, numOperators)));
				if (item->args != NIL)
				{
					TypeName   *typeName1 = (TypeName *) linitial(item->args);
					TypeName   *typeName2 = (TypeName *) lsecond(item->args);

					operOid = LookupOperNameTypeNames(item->name,
													  typeName1,
													  typeName2,
													  false);
				}
				else
				{
					/* Default to binary op on input datatype */
					operOid = LookupOperName(item->name, typeoid, typeoid,
											 false);
				}
				/* Caller must have execute permission on operators */
				funcOid = get_opcode(operOid);
				aclresult = pg_proc_aclcheck(funcOid, GetUserId(),
											 ACL_EXECUTE);
				if (aclresult != ACLCHECK_OK)
					aclcheck_error(aclresult, ACL_KIND_PROC,
								   get_func_name(funcOid));
				/* Save the info */
				member = (OpClassMember *) palloc0(sizeof(OpClassMember));
				member->object = operOid;
				member->number = item->number;
				member->subtype = assignOperSubtype(amoid, typeoid, operOid);
				member->recheck = item->recheck;
				addClassMember(&operators, member, false);
				break;
			case OPCLASS_ITEM_FUNCTION:
				if (item->number <= 0 || item->number > numProcs)
					ereport(ERROR,
							(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
							 errmsg("invalid procedure number %d,"
									" must be between 1 and %d",
									item->number, numProcs)));
				funcOid = LookupFuncNameTypeNames(item->name, item->args,
												  false);
				/* Caller must have execute permission on functions */
				aclresult = pg_proc_aclcheck(funcOid, GetUserId(),
											 ACL_EXECUTE);
				if (aclresult != ACLCHECK_OK)
					aclcheck_error(aclresult, ACL_KIND_PROC,
								   get_func_name(funcOid));
				/* Save the info */
				member = (OpClassMember *) palloc0(sizeof(OpClassMember));
				member->object = funcOid;
				member->number = item->number;
				member->subtype = assignProcSubtype(amoid, typeoid, funcOid);
				addClassMember(&procedures, member, true);
				break;
			case OPCLASS_ITEM_STORAGETYPE:
				if (OidIsValid(storageoid))
					ereport(ERROR,
							(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
						   errmsg("storage type specified more than once")));
				storageoid = typenameTypeId(item->storedtype);
				break;
			default:
				elog(ERROR, "unrecognized item type: %d", item->itemtype);
				break;
		}
	}

	/*
	 * If storagetype is specified, make sure it's legal.
	 */
	if (OidIsValid(storageoid))
	{
		/* Just drop the spec if same as column datatype */
		if (storageoid == typeoid)
			storageoid = InvalidOid;
		else
		{
			/*
			 * Currently, only GiST allows storagetype different from
			 * datatype.  This hardcoded test should be eliminated in favor of
			 * adding another boolean column to pg_am ...
			 */
			if (amoid != GIST_AM_OID)
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
						 errmsg("storage type may not be different from data type for access method \"%s\"",
								stmt->amname)));
		}
	}

	rel = heap_open(OperatorClassRelationId, RowExclusiveLock);

	/*
	 * Make sure there is no existing opclass of this name (this is just to
	 * give a more friendly error message than "duplicate key").
	 */
	if (SearchSysCacheExists(CLAAMNAMENSP,
							 ObjectIdGetDatum(amoid),
							 CStringGetDatum(opcname),
							 ObjectIdGetDatum(namespaceoid),
							 0))
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_OBJECT),
				 errmsg("operator class \"%s\" for access method \"%s\" already exists",
						opcname, stmt->amname)));

	/*
	 * If we are creating a default opclass, check there isn't one already.
	 * (Note we do not restrict this test to visible opclasses; this ensures
	 * that typcache.c can find unique solutions to its questions.)
	 */
	if (stmt->isDefault)
	{
		ScanKeyData skey[1];
		SysScanDesc scan;

		ScanKeyInit(&skey[0],
					Anum_pg_opclass_opcamid,
					BTEqualStrategyNumber, F_OIDEQ,
					ObjectIdGetDatum(amoid));

		scan = systable_beginscan(rel, OpclassAmNameNspIndexId, true,
								  SnapshotNow, 1, skey);

		while (HeapTupleIsValid(tup = systable_getnext(scan)))
		{
			Form_pg_opclass opclass = (Form_pg_opclass) GETSTRUCT(tup);

			if (opclass->opcintype == typeoid && opclass->opcdefault)
				ereport(ERROR,
						(errcode(ERRCODE_DUPLICATE_OBJECT),
						 errmsg("could not make operator class \"%s\" be default for type %s",
								opcname,
								TypeNameToString(stmt->datatype)),
				   errdetail("Operator class \"%s\" already is the default.",
							 NameStr(opclass->opcname))));
		}

		systable_endscan(scan);
	}

	/*
	 * Okay, let's create the pg_opclass entry.
	 */
	for (i = 0; i < Natts_pg_opclass; ++i)
	{
		nulls[i] = ' ';
		values[i] = (Datum) NULL;		/* redundant, but safe */
	}

	i = 0;
	values[i++] = ObjectIdGetDatum(amoid);		/* opcamid */
	namestrcpy(&opcName, opcname);
	values[i++] = NameGetDatum(&opcName);		/* opcname */
	values[i++] = ObjectIdGetDatum(namespaceoid);		/* opcnamespace */
	values[i++] = ObjectIdGetDatum(GetUserId());		/* opcowner */
	values[i++] = ObjectIdGetDatum(typeoid);	/* opcintype */
	values[i++] = BoolGetDatum(stmt->isDefault);		/* opcdefault */
	values[i++] = ObjectIdGetDatum(storageoid); /* opckeytype */

	tup = heap_formtuple(rel->rd_att, values, nulls);

	opclassoid = simple_heap_insert(rel, tup);

	CatalogUpdateIndexes(rel, tup);

	heap_freetuple(tup);

	/*
	 * Now add tuples to pg_amop and pg_amproc tying in the operators and
	 * functions.
	 */
	storeOperators(opclassoid, operators);
	storeProcedures(opclassoid, procedures);

	/*
	 * Create dependencies.  Note: we do not create a dependency link to the
	 * AM, because we don't currently support DROP ACCESS METHOD.
	 */
	myself.classId = OperatorClassRelationId;
	myself.objectId = opclassoid;
	myself.objectSubId = 0;

	/* dependency on namespace */
	referenced.classId = NamespaceRelationId;
	referenced.objectId = namespaceoid;
	referenced.objectSubId = 0;
	recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

	/* dependency on indexed datatype */
	referenced.classId = TypeRelationId;
	referenced.objectId = typeoid;
	referenced.objectSubId = 0;
	recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

	/* dependency on storage datatype */
	if (OidIsValid(storageoid))
	{
		referenced.classId = TypeRelationId;
		referenced.objectId = storageoid;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/* dependencies on operators */
	foreach(l, operators)
	{
		OpClassMember *op = (OpClassMember *) lfirst(l);

		referenced.classId = OperatorRelationId;
		referenced.objectId = op->object;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/* dependencies on procedures */
	foreach(l, procedures)
	{
		OpClassMember *proc = (OpClassMember *) lfirst(l);

		referenced.classId = ProcedureRelationId;
		referenced.objectId = proc->object;
		referenced.objectSubId = 0;
		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
	}

	/* dependency on owner */
	recordDependencyOnOwner(OperatorClassRelationId, opclassoid, GetUserId());

	heap_close(rel, RowExclusiveLock);
}

/*
 * Determine the subtype to assign to an operator, and do any validity
 * checking we can manage
 *
 * Currently this is done using hardwired rules; we don't let the user
 * specify it directly.
 */
static Oid
assignOperSubtype(Oid amoid, Oid typeoid, Oid operOid)
{
	Oid			subtype;
	Operator	optup;
	Form_pg_operator opform;

	/* Subtypes are currently only supported by btree, others use 0 */
	if (amoid != BTREE_AM_OID)
		return InvalidOid;

	optup = SearchSysCache(OPEROID,
						   ObjectIdGetDatum(operOid),
						   0, 0, 0);
	if (optup == NULL)
		elog(ERROR, "cache lookup failed for operator %u", operOid);
	opform = (Form_pg_operator) GETSTRUCT(optup);

	/*
	 * btree operators must be binary ops returning boolean, and the left-side
	 * input type must match the operator class' input type.
	 */
	if (opform->oprkind != 'b')
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("btree operators must be binary")));
	if (opform->oprresult != BOOLOID)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("btree operators must return boolean")));
	if (opform->oprleft != typeoid)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
			  errmsg("btree operators must have index type as left input")));

	/*
	 * The subtype is "default" (0) if oprright matches the operator class,
	 * otherwise it is oprright.
	 */
	if (opform->oprright == typeoid)
		subtype = InvalidOid;
	else
		subtype = opform->oprright;
	ReleaseSysCache(optup);
	return subtype;
}

/*
 * Determine the subtype to assign to a support procedure, and do any validity
 * checking we can manage
 *
 * Currently this is done using hardwired rules; we don't let the user
 * specify it directly.
 */
static Oid
assignProcSubtype(Oid amoid, Oid typeoid, Oid procOid)
{
	Oid			subtype;
	HeapTuple	proctup;
	Form_pg_proc procform;

	/* Subtypes are currently only supported by btree, others use 0 */
	if (amoid != BTREE_AM_OID)
		return InvalidOid;

	proctup = SearchSysCache(PROCOID,
							 ObjectIdGetDatum(procOid),
							 0, 0, 0);
	if (proctup == NULL)
		elog(ERROR, "cache lookup failed for function %u", procOid);
	procform = (Form_pg_proc) GETSTRUCT(proctup);

	/*
	 * btree support procs must be 2-arg procs returning int4, and the first
	 * input type must match the operator class' input type.
	 */
	if (procform->pronargs != 2)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("btree procedures must have two arguments")));
	if (procform->prorettype != INT4OID)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("btree procedures must return integer")));
	if (procform->proargtypes.values[0] != typeoid)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
			errmsg("btree procedures must have index type as first input")));