/*
 * ValidateProtocolFunction -- common code for finding readfn, writefn or validatorfn
 */
static Oid
ValidateProtocolFunction(List *fnName, ExtPtcFuncType fntype)
{
	Oid			fnOid;
	bool		retset;
	bool        retstrict;
	bool        retordered;
	Oid		   *true_oid_array;
	Oid 	    actual_rettype;
	Oid			desired_rettype;
	FuncDetailCode fdresult;
	AclResult	aclresult;
	Oid 		inputTypes[1] = {InvalidOid}; /* dummy */
	int			nargs = 0; /* true for all 3 function types at the moment */
	int			nvargs;
	
	if (fntype == EXTPTC_FUNC_VALIDATOR)
		desired_rettype = VOIDOID;
	else
		desired_rettype = INT4OID;

	/*
	 * func_get_detail looks up the function in the catalogs, does
	 * disambiguation for polymorphic functions, handles inheritance, and
	 * returns the funcid and type and set or singleton status of the
	 * function's return value.  it also returns the true argument types to
	 * the function.
	 */
	fdresult = func_get_detail(fnName, NIL, nargs, inputTypes, false, false,
							   &fnOid, &actual_rettype, &retset, &retstrict,
							   &retordered, &nvargs, &true_oid_array, NULL);

	/* only valid case is a normal function not returning a set */
	if (fdresult != FUNCDETAIL_NORMAL || !OidIsValid(fnOid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("function %s does not exist",
						func_signature_string(fnName, nargs, inputTypes))));
	
	if (retset)
		ereport(ERROR,
				(errcode(ERRCODE_DATATYPE_MISMATCH),
				 errmsg("Invalid protocol function"),
				 errdetail("Protocol functions cannot return sets.")));		

	if (actual_rettype != desired_rettype)
		ereport(ERROR,
				(errcode(ERRCODE_DATATYPE_MISMATCH),
				 errmsg("%s protocol function %s must return %s",
						func_type_to_name(fntype),
						func_signature_string(fnName, nargs, inputTypes),
						(fntype == EXTPTC_FUNC_VALIDATOR ? "void" : "an integer"))));
	
	if (func_volatile(fnOid) == PROVOLATILE_IMMUTABLE)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
				 errmsg("%s protocol function %s is declared IMMUTABLE",
						func_type_to_name(fntype),
						func_signature_string(fnName, nargs, inputTypes)),
				 errhint("PROTOCOL functions must be declared STABLE or VOLATILE")));

	
	/* Check protocol creator has permission to call the function */
	aclresult = pg_proc_aclcheck(fnOid, GetUserId(), ACL_EXECUTE);
	if (aclresult != ACLCHECK_OK)
		aclcheck_error(aclresult, ACL_KIND_PROC, get_func_name(fnOid));

	return fnOid;
}

/*
 * CREATE CONVERSION
 */
ObjectAddress
CreateConversionCommand(CreateConversionStmt *stmt)
{
	Oid			namespaceId;
	char	   *conversion_name;
	AclResult	aclresult;
	int			from_encoding;
	int			to_encoding;
	Oid			funcoid;
	const char *from_encoding_name = stmt->for_encoding_name;
	const char *to_encoding_name = stmt->to_encoding_name;
	List	   *func_name = stmt->func_name;
	static const Oid funcargs[] = {INT4OID, INT4OID, CSTRINGOID, INTERNALOID, INT4OID};
	char		result[1];

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

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

	/* Check the encoding names */
	from_encoding = pg_char_to_encoding(from_encoding_name);
	if (from_encoding < 0)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("source encoding \"%s\" does not exist",
						from_encoding_name)));

	to_encoding = pg_char_to_encoding(to_encoding_name);
	if (to_encoding < 0)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("destination encoding \"%s\" does not exist",
						to_encoding_name)));

	/*
	 * Check the existence of the conversion function. Function name could be
	 * a qualified name.
	 */
	funcoid = LookupFuncName(func_name, sizeof(funcargs) / sizeof(Oid),
							 funcargs, false);

	/* Check it returns VOID, else it's probably the wrong function */
	if (get_func_rettype(funcoid) != VOIDOID)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("encoding conversion function %s must return type %s",
						NameListToString(func_name), "void")));

	/* Check we have EXECUTE rights for the function */
	aclresult = pg_proc_aclcheck(funcoid, GetUserId(), ACL_EXECUTE);
	if (aclresult != ACLCHECK_OK)
		aclcheck_error(aclresult, ACL_KIND_PROC,
					   NameListToString(func_name));

	/*
	 * Check that the conversion function is suitable for the requested source
	 * and target encodings. We do that by calling the function with an empty
	 * string; the conversion function should throw an error if it can't
	 * perform the requested conversion.
	 */
	OidFunctionCall5(funcoid,
					 Int32GetDatum(from_encoding),
					 Int32GetDatum(to_encoding),
					 CStringGetDatum(""),
					 CStringGetDatum(result),
					 Int32GetDatum(0));

	/*
	 * All seem ok, go ahead (possible failure would be a duplicate conversion
	 * name)
	 */
	return ConversionCreate(conversion_name, namespaceId, GetUserId(),
							from_encoding, to_encoding, funcoid, stmt->def);
}

//.........这里部分代码省略.........
		{
			/* Get specific pid slot */
			beentry = pgstat_fetch_stat_beentry(*(int *) (funcctx->user_fctx));
		}
		else
		{
			/* Get the next one in the list */
			beentry = pgstat_fetch_stat_beentry(funcctx->call_cntr + 1);		/* 1-based index */
		}
		if (!beentry)
		{
			int			i;

			for (i = 0; i < sizeof(nulls) / sizeof(nulls[0]); i++)
				nulls[i] = true;

			nulls[4] = false;
			values[4] = CStringGetTextDatum("<backend information not available>");

			tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
			SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
		}

		/* Values available to all callers */
		values[0] = ObjectIdGetDatum(beentry->st_databaseid);
		values[1] = Int32GetDatum(beentry->st_procpid);
		values[2] = ObjectIdGetDatum(beentry->st_userid);
		if (beentry->st_appname)
			values[3] = CStringGetTextDatum(beentry->st_appname);
		else
			nulls[3] = true;

		/* Values only available to same user or superuser */
		if (superuser() || beentry->st_userid == GetUserId())
		{
			if (*(beentry->st_activity) == '\0')
			{
				values[4] = CStringGetTextDatum("<command string not enabled>");
			}
			else
			{
				values[4] = CStringGetTextDatum(beentry->st_activity);
			}

			values[5] = BoolGetDatum(beentry->st_waiting);

			if (beentry->st_xact_start_timestamp != 0)
				values[6] = TimestampTzGetDatum(beentry->st_xact_start_timestamp);
			else
				nulls[6] = true;

			if (beentry->st_activity_start_timestamp != 0)
				values[7] = TimestampTzGetDatum(beentry->st_activity_start_timestamp);
			else
				nulls[7] = true;

			if (beentry->st_proc_start_timestamp != 0)
				values[8] = TimestampTzGetDatum(beentry->st_proc_start_timestamp);
			else
				nulls[8] = true;

			/* A zeroed client addr means we don't know */
			memset(&zero_clientaddr, 0, sizeof(zero_clientaddr));
			if (memcmp(&(beentry->st_clientaddr), &zero_clientaddr,
					   sizeof(zero_clientaddr) == 0))
			{

/*
 * FinishPreparedTransaction: execute COMMIT PREPARED or ROLLBACK PREPARED
 */
void
FinishPreparedTransaction(const char *gid, bool isCommit)
{
	GlobalTransaction gxact;
	TransactionId xid;
	char	   *buf;
	char	   *bufptr;
	TwoPhaseFileHeader *hdr;
	TransactionId latestXid;
	TransactionId *children;
	RelFileNode *commitrels;
	RelFileNode *abortrels;
	RelFileNode *delrels;
	int			ndelrels;
	int			i;

	/*
	 * Validate the GID, and lock the GXACT to ensure that two backends do not
	 * try to commit the same GID at once.
	 */
	gxact = LockGXact(gid, GetUserId());
	xid = gxact->proc.xid;

	/*
	 * Read and validate the state file
	 */
	buf = ReadTwoPhaseFile(xid);
	if (buf == NULL)
		ereport(ERROR,
				(errcode(ERRCODE_DATA_CORRUPTED),
				 errmsg("two-phase state file for transaction %u is corrupt",
						xid)));

	/*
	 * Disassemble the header area
	 */
	hdr = (TwoPhaseFileHeader *) buf;
	Assert(TransactionIdEquals(hdr->xid, xid));
	bufptr = buf + MAXALIGN(sizeof(TwoPhaseFileHeader));
	children = (TransactionId *) bufptr;
	bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
	commitrels = (RelFileNode *) bufptr;
	bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileNode));
	abortrels = (RelFileNode *) bufptr;
	bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileNode));

	/* compute latestXid among all children */
	latestXid = TransactionIdLatest(xid, hdr->nsubxacts, children);

	/*
	 * The order of operations here is critical: make the XLOG entry for
	 * commit or abort, then mark the transaction committed or aborted in
	 * pg_clog, then remove its PGPROC from the global ProcArray (which means
	 * TransactionIdIsInProgress will stop saying the prepared xact is in
	 * progress), then run the post-commit or post-abort callbacks. The
	 * callbacks will release the locks the transaction held.
	 */
	if (isCommit)
		RecordTransactionCommitPrepared(xid,
										hdr->nsubxacts, children,
										hdr->ncommitrels, commitrels);
	else
		RecordTransactionAbortPrepared(xid,
									   hdr->nsubxacts, children,
									   hdr->nabortrels, abortrels);

	ProcArrayRemove(&gxact->proc, latestXid);

	/*
	 * In case we fail while running the callbacks, mark the gxact invalid so
	 * no one else will try to commit/rollback, and so it can be recycled
	 * properly later.	It is still locked by our XID so it won't go away yet.
	 *
	 * (We assume it's safe to do this without taking TwoPhaseStateLock.)
	 */
	gxact->valid = false;

	/*
	 * We have to remove any files that were supposed to be dropped. For
	 * consistency with the regular xact.c code paths, must do this before
	 * releasing locks, so do it before running the callbacks.
	 *
	 * NB: this code knows that we couldn't be dropping any temp rels ...
	 */
	if (isCommit)
	{
		delrels = commitrels;
		ndelrels = hdr->ncommitrels;
	}
	else
	{
		delrels = abortrels;
		ndelrels = hdr->nabortrels;
	}
	for (i = 0; i < ndelrels; i++)
	{
		SMgrRelation srel = smgropen(delrels[i]);
//.........这里部分代码省略.........

void pgUser::ShowDependents(frmMain *form, ctlListView *referencedBy, const wxString &where)
{
    form->StartMsg(_(" Retrieving user owned objects"));

    referencedBy->ClearAll();
    referencedBy->AddColumn(_("Type"), 60);
    referencedBy->AddColumn(_("Database"), 80);
    referencedBy->AddColumn(_("Name"), 300);

    wxString uid = NumToStr(GetUserId());
    wxString sysoid = NumToStr(GetConnection()->GetLastSystemOID());

    wxArrayString dblist;

    pgSet *set;
    if (GetConnection()->BackendMinimumVersion(7, 5))
        set = GetConnection()->ExecuteSet(
                  wxT("SELECT 'd' as type, datname, datallowconn, datdba\n")
                  wxT("  FROM pg_database db\n")
                  wxT("UNION\n")
                  wxT("SELECT 'M', spcname, null, null\n")
                  wxT("  FROM pg_tablespace where spcowner=") + uid + wxT("\n")
                  wxT(" ORDER BY 1, 2"));
    else
        set = GetConnection()->ExecuteSet(
                  wxT("SELECT 'd' as type, datname, datallowconn, datdba\n")
                  wxT("  FROM pg_database db"));

    if (set)
    {
        while (!set->Eof())
        {
            wxString name = set->GetVal(wxT("datname"));
            if (set->GetVal(wxT("type")) == wxT("d"))
            {
                if (set->GetBool(wxT("datallowconn")))
                    dblist.Add(name);
                if (GetUserId() == set->GetLong(wxT("datdba")))
                    referencedBy->AppendItem(databaseFactory.GetIconId(), _("Database"), name);
            }
            else
                referencedBy->AppendItem(tablespaceFactory.GetIconId(), _("Tablespace"), wxEmptyString, name);

            set->MoveNext();
        }
        delete set;
    }

    FillOwned(form->GetBrowser(), referencedBy, dblist,
              wxT("SELECT cl.relkind, COALESCE(cin.nspname, cln.nspname) as nspname, COALESCE(ci.relname, cl.relname) as relname, cl.relname as indname\n")
              wxT("  FROM pg_class cl\n")
              wxT("  JOIN pg_namespace cln ON cl.relnamespace=cln.oid\n")
              wxT("  LEFT OUTER JOIN pg_index ind ON ind.indexrelid=cl.oid\n")
              wxT("  LEFT OUTER JOIN pg_class ci ON ind.indrelid=ci.oid\n")
              wxT("  LEFT OUTER JOIN pg_namespace cin ON ci.relnamespace=cin.oid\n")
              wxT(" WHERE cl.relowner = ") + uid + wxT(" AND cl.oid > ") + sysoid + wxT("\n")
              wxT("UNION ALL\n")
              wxT("SELECT 'n', null, nspname, null\n")
              wxT("  FROM pg_namespace nsp WHERE nspowner = ") + uid + wxT(" AND nsp.oid > ") + sysoid + wxT("\n")
              wxT("UNION ALL\n")
              wxT("SELECT CASE WHEN typtype='d' THEN 'd' ELSE 'y' END, null, typname, null\n")
              wxT("  FROM pg_type ty WHERE typowner = ") + uid + wxT(" AND ty.oid > ") + sysoid + wxT("\n")
              wxT("UNION ALL\n")
              wxT("SELECT 'C', null, conname, null\n")
              wxT("  FROM pg_conversion co WHERE conowner = ") + uid + wxT(" AND co.oid > ") + sysoid + wxT("\n")
              wxT("UNION ALL\n")
              wxT("SELECT CASE WHEN prorettype=") + NumToStr(PGOID_TYPE_TRIGGER) + wxT(" THEN 'T' ELSE 'p' END, null, proname, null\n")
              wxT("  FROM pg_proc pr WHERE proowner = ") + uid + wxT(" AND pr.oid > ") + sysoid + wxT("\n")
              wxT("UNION ALL\n")
              wxT("SELECT 'o', null, oprname || '('::text || ")
              wxT("COALESCE(tl.typname, ''::text) || ")
              wxT("CASE WHEN tl.oid IS NOT NULL AND tr.oid IS NOT NULL THEN ','::text END || ")
              wxT("COALESCE(tr.typname, ''::text) || ')'::text, null\n")
              wxT("  FROM pg_operator op\n")
              wxT("  LEFT JOIN pg_type tl ON tl.oid=op.oprleft\n")
              wxT("  LEFT JOIN pg_type tr ON tr.oid=op.oprright\n")
              wxT(" WHERE oprowner = ") + uid + wxT(" AND op.oid > ") + sysoid + wxT("\n")
              wxT(" ORDER BY 1,2,3"));

    form->EndMsg(set != 0);
}

/*
 * Retrieve statement statistics.
 */
Datum
pg_stat_statements(PG_FUNCTION_ARGS)
{
	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
	TupleDesc	tupdesc;
	Tuplestorestate *tupstore;
	MemoryContext per_query_ctx;
	MemoryContext oldcontext;
	Oid			userid = GetUserId();
	bool		is_superuser = superuser();
	HASH_SEQ_STATUS hash_seq;
	pgssEntry  *entry;

	if (!pgss || !pgss_hash)
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("pg_stat_statements must be loaded via shared_preload_libraries")));

	/* check to see if caller supports us returning a tuplestore */
	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("set-valued function called in context that cannot accept a set")));
	if (!(rsinfo->allowedModes & SFRM_Materialize))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("materialize mode required, but it is not " \
						"allowed in this context")));

	/* Build a tuple descriptor for our result type */
	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
		elog(ERROR, "return type must be a row type");

	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
	oldcontext = MemoryContextSwitchTo(per_query_ctx);

	tupstore = tuplestore_begin_heap(true, false, work_mem);
	rsinfo->returnMode = SFRM_Materialize;
	rsinfo->setResult = tupstore;
	rsinfo->setDesc = tupdesc;

	MemoryContextSwitchTo(oldcontext);

	LWLockAcquire(pgss->lock, LW_SHARED);

	hash_seq_init(&hash_seq, pgss_hash);
	while ((entry = hash_seq_search(&hash_seq)) != NULL)
	{
		Datum		values[PG_STAT_STATEMENTS_COLS];
		bool		nulls[PG_STAT_STATEMENTS_COLS];
		int			i = 0;
		Counters	tmp;

		memset(values, 0, sizeof(values));
		memset(nulls, 0, sizeof(nulls));

		values[i++] = ObjectIdGetDatum(entry->key.userid);
		values[i++] = ObjectIdGetDatum(entry->key.dbid);

		if (is_superuser || entry->key.userid == userid)
		{
			char	   *qstr;

			qstr = (char *)
				pg_do_encoding_conversion((unsigned char *) entry->query,
										  entry->key.query_len,
										  entry->key.encoding,
										  GetDatabaseEncoding());
			values[i++] = CStringGetTextDatum(qstr);
			if (qstr != entry->query)
				pfree(qstr);
		}
		else
			values[i++] = CStringGetTextDatum("<insufficient privilege>");

		/* copy counters to a local variable to keep locking time short */
		{
			volatile pgssEntry *e = (volatile pgssEntry *) entry;

			SpinLockAcquire(&e->mutex);
			tmp = e->counters;
			SpinLockRelease(&e->mutex);
		}

		values[i++] = Int64GetDatumFast(tmp.calls);
		values[i++] = Float8GetDatumFast(tmp.total_time);
		values[i++] = Int64GetDatumFast(tmp.rows);
		values[i++] = Int64GetDatumFast(tmp.shared_blks_hit);
		values[i++] = Int64GetDatumFast(tmp.shared_blks_read);
		values[i++] = Int64GetDatumFast(tmp.shared_blks_written);
		values[i++] = Int64GetDatumFast(tmp.local_blks_hit);
		values[i++] = Int64GetDatumFast(tmp.local_blks_read);
		values[i++] = Int64GetDatumFast(tmp.local_blks_written);
		values[i++] = Int64GetDatumFast(tmp.temp_blks_read);
		values[i++] = Int64GetDatumFast(tmp.temp_blks_written);

		Assert(i == PG_STAT_STATEMENTS_COLS);
//.........这里部分代码省略.........

/*
 *	DefineAggregate
 *
 * "oldstyle" signals the old (pre-8.2) style where the aggregate input type
 * is specified by a BASETYPE element in the parameters.  Otherwise,
 * "args" is a pair, whose first element is a list of FunctionParameter structs
 * defining the agg's arguments (both direct and aggregated), and whose second
 * element is an Integer node with the number of direct args, or -1 if this
 * isn't an ordered-set aggregate.
 * "parameters" is a list of DefElem representing the agg's definition clauses.
 */
ObjectAddress
DefineAggregate(List *name, List *args, bool oldstyle, List *parameters,
				const char *queryString)
{
	char	   *aggName;
	Oid			aggNamespace;
	AclResult	aclresult;
	char		aggKind = AGGKIND_NORMAL;
	List	   *transfuncName = NIL;
	List	   *finalfuncName = NIL;
	List	   *combinefuncName = NIL;
	List	   *serialfuncName = NIL;
	List	   *deserialfuncName = NIL;
	List	   *mtransfuncName = NIL;
	List	   *minvtransfuncName = NIL;
	List	   *mfinalfuncName = NIL;
	bool		finalfuncExtraArgs = false;
	bool		mfinalfuncExtraArgs = false;
	List	   *sortoperatorName = NIL;
	TypeName   *baseType = NULL;
	TypeName   *transType = NULL;
	TypeName   *mtransType = NULL;
	int32		transSpace = 0;
	int32		mtransSpace = 0;
	char	   *initval = NULL;
	char	   *minitval = NULL;
	char	   *parallel = NULL;
	int			numArgs;
	int			numDirectArgs = 0;
	oidvector  *parameterTypes;
	ArrayType  *allParameterTypes;
	ArrayType  *parameterModes;
	ArrayType  *parameterNames;
	List	   *parameterDefaults;
	Oid			variadicArgType;
	Oid			transTypeId;
	Oid			mtransTypeId = InvalidOid;
	char		transTypeType;
	char		mtransTypeType = 0;
	char		proparallel = PROPARALLEL_UNSAFE;
	ListCell   *pl;

	/* Convert list of names to a name and namespace */
	aggNamespace = QualifiedNameGetCreationNamespace(name, &aggName);

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

	/* Deconstruct the output of the aggr_args grammar production */
	if (!oldstyle)
	{
		Assert(list_length(args) == 2);
		numDirectArgs = intVal(lsecond(args));
		if (numDirectArgs >= 0)
			aggKind = AGGKIND_ORDERED_SET;
		else
			numDirectArgs = 0;
		args = (List *) linitial(args);
	}

	/* Examine aggregate's definition clauses */
	foreach(pl, parameters)
	{
		DefElem    *defel = (DefElem *) lfirst(pl);

		/*
		 * sfunc1, stype1, and initcond1 are accepted as obsolete spellings
		 * for sfunc, stype, initcond.
		 */
		if (pg_strcasecmp(defel->defname, "sfunc") == 0)
			transfuncName = defGetQualifiedName(defel);
		else if (pg_strcasecmp(defel->defname, "sfunc1") == 0)
			transfuncName = defGetQualifiedName(defel);
		else if (pg_strcasecmp(defel->defname, "finalfunc") == 0)
			finalfuncName = defGetQualifiedName(defel);
		else if (pg_strcasecmp(defel->defname, "combinefunc") == 0)
			combinefuncName = defGetQualifiedName(defel);
		else if (pg_strcasecmp(defel->defname, "serialfunc") == 0)
			serialfuncName = defGetQualifiedName(defel);
		else if (pg_strcasecmp(defel->defname, "deserialfunc") == 0)
			deserialfuncName = defGetQualifiedName(defel);
		else if (pg_strcasecmp(defel->defname, "msfunc") == 0)
			mtransfuncName = defGetQualifiedName(defel);
		else if (pg_strcasecmp(defel->defname, "minvfunc") == 0)
			minvtransfuncName = defGetQualifiedName(defel);
		else if (pg_strcasecmp(defel->defname, "mfinalfunc") == 0)
//.........这里部分代码省略.........

/*
 * Drop a table space
 *
 * Be careful to check that the tablespace is empty.
 */
void
DropTableSpace(DropTableSpaceStmt *stmt)
{
#ifdef HAVE_SYMLINK
	char	   *tablespacename = stmt->tablespacename;
	HeapScanDesc scandesc;
	Relation	rel;
	HeapTuple	tuple;
	ScanKeyData entry[1];
	Oid			tablespaceoid;

	/*
	 * Find the target tuple
	 */
	rel = heap_open(TableSpaceRelationId, RowExclusiveLock);

	ScanKeyInit(&entry[0],
				Anum_pg_tablespace_spcname,
				BTEqualStrategyNumber, F_NAMEEQ,
				CStringGetDatum(tablespacename));
	scandesc = heap_beginscan_catalog(rel, 1, entry);
	tuple = heap_getnext(scandesc, ForwardScanDirection);

	if (!HeapTupleIsValid(tuple))
	{
		if (!stmt->missing_ok)
		{
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_OBJECT),
					 errmsg("tablespace \"%s\" does not exist",
							tablespacename)));
		}
		else
		{
			ereport(NOTICE,
					(errmsg("tablespace \"%s\" does not exist, skipping",
							tablespacename)));
			/* XXX I assume I need one or both of these next two calls */
			heap_endscan(scandesc);
			heap_close(rel, NoLock);
		}
		return;
	}

	tablespaceoid = HeapTupleGetOid(tuple);

	/* Must be tablespace owner */
	if (!pg_tablespace_ownercheck(tablespaceoid, GetUserId()))
		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_TABLESPACE,
					   tablespacename);

	/* Disallow drop of the standard tablespaces, even by superuser */
	if (tablespaceoid == GLOBALTABLESPACE_OID ||
		tablespaceoid == DEFAULTTABLESPACE_OID)
		aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_TABLESPACE,
					   tablespacename);

	/* DROP hook for the tablespace being removed */
	InvokeObjectDropHook(TableSpaceRelationId, tablespaceoid, 0);

	/*
	 * Remove the pg_tablespace tuple (this will roll back if we fail below)
	 */
	simple_heap_delete(rel, &tuple->t_self);

	heap_endscan(scandesc);

	/*
	 * Remove any comments or security labels on this tablespace.
	 */
	DeleteSharedComments(tablespaceoid, TableSpaceRelationId);
	DeleteSharedSecurityLabel(tablespaceoid, TableSpaceRelationId);

	/*
	 * Remove dependency on owner.
	 */
	deleteSharedDependencyRecordsFor(TableSpaceRelationId, tablespaceoid, 0);

	/*
	 * Acquire TablespaceCreateLock to ensure that no TablespaceCreateDbspace
	 * is running concurrently.
	 */
	LWLockAcquire(TablespaceCreateLock, LW_EXCLUSIVE);

	/*
	 * Try to remove the physical infrastructure.
	 */
	if (!destroy_tablespace_directories(tablespaceoid, false))
	{
		/*
		 * Not all files deleted?  However, there can be lingering empty files
		 * in the directories, left behind by for example DROP TABLE, that
		 * have been scheduled for deletion at next checkpoint (see comments
		 * in mdunlink() for details).  We could just delete them immediately,
		 * but we can't tell them apart from important data files that we
//.........这里部分代码省略.........

/*
 * Rename a tablespace
 */
ObjectAddress
RenameTableSpace(const char *oldname, const char *newname)
{
	Oid			tspId;
	Relation	rel;
	ScanKeyData entry[1];
	HeapScanDesc scan;
	HeapTuple	tup;
	HeapTuple	newtuple;
	Form_pg_tablespace newform;
	ObjectAddress address;

	/* Search pg_tablespace */
	rel = heap_open(TableSpaceRelationId, RowExclusiveLock);

	ScanKeyInit(&entry[0],
				Anum_pg_tablespace_spcname,
				BTEqualStrategyNumber, F_NAMEEQ,
				CStringGetDatum(oldname));
	scan = heap_beginscan_catalog(rel, 1, entry);
	tup = heap_getnext(scan, ForwardScanDirection);
	if (!HeapTupleIsValid(tup))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("tablespace \"%s\" does not exist",
						oldname)));

	tspId = HeapTupleGetOid(tup);
	newtuple = heap_copytuple(tup);
	newform = (Form_pg_tablespace) GETSTRUCT(newtuple);

	heap_endscan(scan);

	/* Must be owner */
	if (!pg_tablespace_ownercheck(HeapTupleGetOid(newtuple), GetUserId()))
		aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_TABLESPACE, oldname);

	/* Validate new name */
	if (!allowSystemTableMods && IsReservedName(newname))
		ereport(ERROR,
				(errcode(ERRCODE_RESERVED_NAME),
				 errmsg("unacceptable tablespace name \"%s\"", newname),
		errdetail("The prefix \"pg_\" is reserved for system tablespaces.")));

	/* Make sure the new name doesn't exist */
	ScanKeyInit(&entry[0],
				Anum_pg_tablespace_spcname,
				BTEqualStrategyNumber, F_NAMEEQ,
				CStringGetDatum(newname));
	scan = heap_beginscan_catalog(rel, 1, entry);
	tup = heap_getnext(scan, ForwardScanDirection);
	if (HeapTupleIsValid(tup))
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_OBJECT),
				 errmsg("tablespace \"%s\" already exists",
						newname)));

	heap_endscan(scan);

	/* OK, update the entry */
	namestrcpy(&(newform->spcname), newname);

	simple_heap_update(rel, &newtuple->t_self, newtuple);
	CatalogUpdateIndexes(rel, newtuple);

	InvokeObjectPostAlterHook(TableSpaceRelationId, tspId, 0);

	ObjectAddressSet(address, TableSpaceRelationId, tspId);

	heap_close(rel, NoLock);

	return address;
}

/* check_hook: validate new temp_tablespaces */
bool
check_temp_tablespaces(char **newval, void **extra, GucSource source)
{
	char	   *rawname;
	List	   *namelist;

	/* Need a modifiable copy of string */
	rawname = pstrdup(*newval);

	/* Parse string into list of identifiers */
	if (!SplitIdentifierString(rawname, ',', &namelist))
	{
		/* syntax error in name list */
		GUC_check_errdetail("List syntax is invalid.");
		pfree(rawname);
		list_free(namelist);
		return false;
	}

	/*
	 * If we aren't inside a transaction, we cannot do database access so
	 * cannot verify the individual names.  Must accept the list on faith.
	 * Fortunately, there's then also no need to pass the data to fd.c.
	 */
	if (IsTransactionState())
	{
		temp_tablespaces_extra *myextra;
		Oid		   *tblSpcs;
		int			numSpcs;
		ListCell   *l;

		/* temporary workspace until we are done verifying the list */
		tblSpcs = (Oid *) palloc(list_length(namelist) * sizeof(Oid));
		numSpcs = 0;
		foreach(l, namelist)
		{
			char	   *curname = (char *) lfirst(l);
			Oid			curoid;
			AclResult	aclresult;

			/* Allow an empty string (signifying database default) */
			if (curname[0] == '\0')
			{
				tblSpcs[numSpcs++] = InvalidOid;
				continue;
			}

			/*
			 * In an interactive SET command, we ereport for bad info.  When
			 * source == PGC_S_TEST, don't throw a hard error for a
			 * nonexistent tablespace, only a NOTICE.  See comments in guc.h.
			 */
			curoid = get_tablespace_oid(curname, source <= PGC_S_TEST);
			if (curoid == InvalidOid)
			{
				if (source == PGC_S_TEST)
					ereport(NOTICE,
							(errcode(ERRCODE_UNDEFINED_OBJECT),
							 errmsg("tablespace \"%s\" does not exist",
									curname)));
				continue;
			}

			/*
			 * Allow explicit specification of database's default tablespace
			 * in temp_tablespaces without triggering permissions checks.
			 */
			if (curoid == MyDatabaseTableSpace)
			{
				tblSpcs[numSpcs++] = InvalidOid;
				continue;
			}

			/* Check permissions, similarly complaining only if interactive */
			aclresult = pg_tablespace_aclcheck(curoid, GetUserId(),
											   ACL_CREATE);
			if (aclresult != ACLCHECK_OK)
			{
				if (source >= PGC_S_INTERACTIVE)
					aclcheck_error(aclresult, ACL_KIND_TABLESPACE, curname);
				continue;
			}

			tblSpcs[numSpcs++] = curoid;
		}

		/* Now prepare an "extra" struct for assign_temp_tablespaces */
		myextra = malloc(offsetof(temp_tablespaces_extra, tblSpcs) +
						 numSpcs * sizeof(Oid));
		if (!myextra)
			return false;
		myextra->numSpcs = numSpcs;
		memcpy(myextra->tblSpcs, tblSpcs, numSpcs * sizeof(Oid));
		*extra = (void *) myextra;

		pfree(tblSpcs);
	}

/*
 * Create a table space
 *
 * Only superusers can create a tablespace. This seems a reasonable restriction
 * since we're determining the system layout and, anyway, we probably have
 * root if we're doing this kind of activity
 */
Oid
CreateTableSpace(CreateTableSpaceStmt *stmt)
{
#ifdef HAVE_SYMLINK
	Relation	rel;
	Datum		values[Natts_pg_tablespace];
	bool		nulls[Natts_pg_tablespace];
	HeapTuple	tuple;
	Oid			tablespaceoid;
	char	   *location;
	Oid			ownerId;
	Datum		newOptions;

	/* Must be super user */
	if (!superuser())
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
				 errmsg("permission denied to create tablespace \"%s\"",
						stmt->tablespacename),
				 errhint("Must be superuser to create a tablespace.")));

	/* However, the eventual owner of the tablespace need not be */
	if (stmt->owner)
		ownerId = get_rolespec_oid(stmt->owner, false);
	else
		ownerId = GetUserId();

	/* Unix-ify the offered path, and strip any trailing slashes */
	location = pstrdup(stmt->location);
	canonicalize_path(location);

	/* disallow quotes, else CREATE DATABASE would be at risk */
	if (strchr(location, '\''))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_NAME),
				 errmsg("tablespace location cannot contain single quotes")));

	/*
	 * Allowing relative paths seems risky
	 *
	 * this also helps us ensure that location is not empty or whitespace
	 */
	if (!is_absolute_path(location))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("tablespace location must be an absolute path")));

	/*
	 * Check that location isn't too long. Remember that we're going to append
	 * 'PG_XXX/<dboid>/<relid>_<fork>.<nnn>'.  FYI, we never actually
	 * reference the whole path here, but mkdir() uses the first two parts.
	 */
	if (strlen(location) + 1 + strlen(TABLESPACE_VERSION_DIRECTORY) + 1 +
	  OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1 + OIDCHARS > MAXPGPATH)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("tablespace location \"%s\" is too long",
						location)));

	/* Warn if the tablespace is in the data directory. */
	if (path_is_prefix_of_path(DataDir, location))
		ereport(WARNING,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("tablespace location should not be inside the data directory")));

	/*
	 * Disallow creation of tablespaces named "pg_xxx"; we reserve this
	 * namespace for system purposes.
	 */
	if (!allowSystemTableMods && IsReservedName(stmt->tablespacename))
		ereport(ERROR,
				(errcode(ERRCODE_RESERVED_NAME),
				 errmsg("unacceptable tablespace name \"%s\"",
						stmt->tablespacename),
		errdetail("The prefix \"pg_\" is reserved for system tablespaces.")));

	/*
	 * Check that there is no other tablespace by this name.  (The unique
	 * index would catch this anyway, but might as well give a friendlier
	 * message.)
	 */
	if (OidIsValid(get_tablespace_oid(stmt->tablespacename, true)))
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_OBJECT),
				 errmsg("tablespace \"%s\" already exists",
						stmt->tablespacename)));

	/*
	 * Insert tuple into pg_tablespace.  The purpose of doing this first is to
	 * lock the proposed tablename against other would-be creators. The
	 * insertion will roll back if we find problems below.
	 */
	rel = heap_open(TableSpaceRelationId, RowExclusiveLock);
//.........这里部分代码省略.........

/*
 * lookup_agg_function
 * common code for finding aggregate support functions
 *
 * fnName: possibly-schema-qualified function name
 * nargs, input_types: expected function argument types
 * variadicArgType: type of variadic argument if any, else InvalidOid
 *
 * Returns OID of function, and stores its return type into *rettype
 *
 * NB: must not scribble on input_types[], as we may re-use those
 */
static Oid
lookup_agg_function(List *fnName,
					int nargs,
					Oid *input_types,
					Oid variadicArgType,
					Oid *rettype)
{
	Oid			fnOid;
	bool		retset;
	int			nvargs;
	Oid			vatype;
	Oid		   *true_oid_array;
	FuncDetailCode fdresult;
	AclResult	aclresult;
	int			i;

	/*
	 * func_get_detail looks up the function in the catalogs, does
	 * disambiguation for polymorphic functions, handles inheritance, and
	 * returns the funcid and type and set or singleton status of the
	 * function's return value.  it also returns the true argument types to
	 * the function.
	 */
	fdresult = func_get_detail(fnName, NIL, NIL,
							   nargs, input_types, false, false,
							   &fnOid, rettype, &retset,
							   &nvargs, &vatype,
							   &true_oid_array, NULL);

	/* only valid case is a normal function not returning a set */
	if (fdresult != FUNCDETAIL_NORMAL || !OidIsValid(fnOid))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("function %s does not exist",
						func_signature_string(fnName, nargs,
											  NIL, input_types))));
	if (retset)
		ereport(ERROR,
				(errcode(ERRCODE_DATATYPE_MISMATCH),
				 errmsg("function %s returns a set",
						func_signature_string(fnName, nargs,
											  NIL, input_types))));

	/*
	 * If the agg is declared to take VARIADIC ANY, the underlying functions
	 * had better be declared that way too, else they may receive too many
	 * parameters; but func_get_detail would have been happy with plain ANY.
	 * (Probably nothing very bad would happen, but it wouldn't work as the
	 * user expects.)  Other combinations should work without any special
	 * pushups, given that we told func_get_detail not to expand VARIADIC.
	 */
	if (variadicArgType == ANYOID && vatype != ANYOID)
		ereport(ERROR,
				(errcode(ERRCODE_DATATYPE_MISMATCH),
				 errmsg("function %s must accept VARIADIC ANY to be used in this aggregate",
						func_signature_string(fnName, nargs,
											  NIL, input_types))));

	/*
	 * If there are any polymorphic types involved, enforce consistency, and
	 * possibly refine the result type.  It's OK if the result is still
	 * polymorphic at this point, though.
	 */
	*rettype = enforce_generic_type_consistency(input_types,
												true_oid_array,
												nargs,
												*rettype,
												true);

	/*
	 * func_get_detail will find functions requiring run-time argument type
	 * coercion, but nodeAgg.c isn't prepared to deal with that
	 */
	for (i = 0; i < nargs; i++)
	{
		if (!IsBinaryCoercible(input_types[i], true_oid_array[i]))
			ereport(ERROR,
					(errcode(ERRCODE_DATATYPE_MISMATCH),
					 errmsg("function %s requires run-time type coercion",
							func_signature_string(fnName, nargs,
												  NIL, true_oid_array))));
	}

	/* Check aggregate creator has permission to call the function */
	aclresult = pg_proc_aclcheck(fnOid, GetUserId(), ACL_EXECUTE);
	if (aclresult != ACLCHECK_OK)
		aclcheck_error(aclresult, OBJECT_FUNCTION, get_func_name(fnOid));

//.........这里部分代码省略.........

//.........这里部分代码省略.........
		else
		{
			/*
			 * If no finalfn, aggregate result type is type of the state value
			 */
			rettype = aggmTransType;
		}
		Assert(OidIsValid(rettype));
		if (rettype != finaltype)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
					 errmsg("moving-aggregate implementation returns type %s, but plain implementation returns type %s",
							format_type_be(aggmTransType),
							format_type_be(aggTransType))));
	}

	/* handle sortop, if supplied */
	if (aggsortopName)
	{
		if (numArgs != 1)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
					 errmsg("sort operator can only be specified for single-argument aggregates")));
		sortop = LookupOperName(NULL, aggsortopName,
								aggArgTypes[0], aggArgTypes[0],
								false, -1);
	}

	/*
	 * permission checks on used types
	 */
	for (i = 0; i < numArgs; i++)
	{
		aclresult = pg_type_aclcheck(aggArgTypes[i], GetUserId(), ACL_USAGE);
		if (aclresult != ACLCHECK_OK)
			aclcheck_error_type(aclresult, aggArgTypes[i]);
	}

	aclresult = pg_type_aclcheck(aggTransType, GetUserId(), ACL_USAGE);
	if (aclresult != ACLCHECK_OK)
		aclcheck_error_type(aclresult, aggTransType);

	if (OidIsValid(aggmTransType))
	{
		aclresult = pg_type_aclcheck(aggmTransType, GetUserId(), ACL_USAGE);
		if (aclresult != ACLCHECK_OK)
			aclcheck_error_type(aclresult, aggmTransType);
	}

	aclresult = pg_type_aclcheck(finaltype, GetUserId(), ACL_USAGE);
	if (aclresult != ACLCHECK_OK)
		aclcheck_error_type(aclresult, finaltype);


	/*
	 * Everything looks okay.  Try to create the pg_proc entry for the
	 * aggregate.  (This could fail if there's already a conflicting entry.)
	 */

	myself = ProcedureCreate(aggName,
							 aggNamespace,
							 false, /* no replacement */
							 false, /* doesn't return a set */
							 finaltype, /* returnType */
							 GetUserId(),	/* proowner */
							 INTERNALlanguageId,	/* languageObjectId */

/*
 * ExtProtocolCreateWithOid
 */
Oid
ExtProtocolCreateWithOid(const char		*protocolName,
					     List			*readfuncName,
					     List			*writefuncName,
					     List			*validatorfuncName,					   
					     Oid			 protOid,
					     bool			 trusted)
{
	Relation	rel;
	HeapTuple	tup;
	bool		nulls[Natts_pg_extprotocol];
	Datum		values[Natts_pg_extprotocol];
	Oid			readfn = InvalidOid;
	Oid			writefn = InvalidOid;
	Oid			validatorfn = InvalidOid;
	NameData	prtname;
	int			i;
	ObjectAddress myself,
				referenced;
	Oid 		ownerId = GetUserId();
	cqContext	cqc;
	cqContext	cqc2;
	cqContext  *pcqCtx;

	/* sanity checks (caller should have caught these) */
	if (!protocolName)
		elog(ERROR, "no protocol name supplied");

	if (!readfuncName && !writefuncName)
		elog(ERROR, "protocol must have at least one of readfunc or writefunc");

	/*
	 * Until we add system protocols to pg_extprotocol, make sure no
	 * protocols with the same name are created.
	 */
	if (strcasecmp(protocolName, "file") == 0 ||
		strcasecmp(protocolName, "http") == 0 ||
		strcasecmp(protocolName, "gpfdist") == 0 ||
		strcasecmp(protocolName, "gpfdists") == 0)
	{
		ereport(ERROR,
				(errcode(ERRCODE_RESERVED_NAME),
				 errmsg("protocol \"%s\" already exists",
						 protocolName),
				 errhint("pick a different protocol name")));
	}

	rel = heap_open(ExtprotocolRelationId, RowExclusiveLock);

	pcqCtx = caql_beginscan(
			caql_addrel(cqclr(&cqc), rel),
			cql("INSERT INTO pg_extprotocol",
				NULL));

	/* make sure there is no existing protocol of same name */
	if (caql_getcount(
				caql_addrel(cqclr(&cqc2), rel),
				cql("SELECT COUNT(*) FROM pg_extprotocol "
					" WHERE ptcname = :1 ",
					CStringGetDatum((char *) protocolName))))
	{
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_OBJECT),
				 errmsg("protocol \"%s\" already exists", 
						protocolName)));
	}

	/*
	 * function checks: if supplied, check existence and correct signature in the catalog
	 */
	
	if (readfuncName)
		readfn = ValidateProtocolFunction(readfuncName, EXTPTC_FUNC_READER);

	if (writefuncName)
		writefn = ValidateProtocolFunction(writefuncName, EXTPTC_FUNC_WRITER);				

	if (validatorfuncName)
		validatorfn = ValidateProtocolFunction(validatorfuncName, EXTPTC_FUNC_VALIDATOR);

	/*
	 * Everything looks okay.  Try to create the pg_extprotocol entry for the
	 * protocol.  (This could fail if there's already a conflicting entry.)
	 */

	/* initialize nulls and values */
	for (i = 0; i < Natts_pg_extprotocol; i++)
	{
		nulls[i] = false;
		values[i] = (Datum) 0;
	}
	namestrcpy(&prtname, protocolName);
	values[Anum_pg_extprotocol_ptcname - 1] = NameGetDatum(&prtname);
	values[Anum_pg_extprotocol_ptcreadfn - 1] = ObjectIdGetDatum(readfn);
	values[Anum_pg_extprotocol_ptcwritefn - 1] = ObjectIdGetDatum(writefn);
	values[Anum_pg_extprotocol_ptcvalidatorfn - 1] = ObjectIdGetDatum(validatorfn);
	values[Anum_pg_extprotocol_ptcowner - 1] = ObjectIdGetDatum(ownerId);
//.........这里部分代码省略.........

/*
 * BuildDescForRelation
 *
 * Given a relation schema (list of ColumnDef nodes), build a TupleDesc.
 *
 * Note: the default assumption is no OIDs; caller may modify the returned
 * TupleDesc if it wants OIDs.  Also, tdtypeid will need to be filled in
 * later on.
 */
TupleDesc
BuildDescForRelation(List *schema)
{
	int			natts;
	AttrNumber	attnum;
	ListCell   *l;
	TupleDesc	desc;
	bool		has_not_null;
	char	   *attname;
	Oid			atttypid;
	int32		atttypmod;
	Oid			attcollation;
	int			attdim;

	/*
	 * allocate a new tuple descriptor
	 */
	natts = list_length(schema);
	desc = CreateTemplateTupleDesc(natts, false);
	has_not_null = false;

	attnum = 0;

	foreach(l, schema)
	{
		ColumnDef  *entry = lfirst(l);
		AclResult	aclresult;

		/*
		 * for each entry in the list, get the name and type information from
		 * the list and have TupleDescInitEntry fill in the attribute
		 * information we need.
		 */
		attnum++;

		attname = entry->colname;
		typenameTypeIdAndMod(NULL, entry->typeName, &atttypid, &atttypmod);

		aclresult