C++ SysCacheGetAttr函数代码示例

/*
 * Check whether the function is IMMUTABLE.
 */
bool
is_immutable_func(Oid funcid)
{
	HeapTuple		tp;
	bool			isnull;
	Datum			datum;

	tp = SearchSysCache(PROCOID, ObjectIdGetDatum(funcid), 0, 0, 0);
	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for function %u", funcid);

#ifdef DEBUG_FDW
	/* print function name and its immutability */
	{
		char		   *proname;
		datum = SysCacheGetAttr(PROCOID, tp, Anum_pg_proc_proname, &isnull);
		proname = pstrdup(DatumGetName(datum)->data);
		elog(DEBUG1, "func %s(%u) is%s immutable", proname, funcid,
			(DatumGetChar(datum) == PROVOLATILE_IMMUTABLE) ? "" : " not");
		pfree(proname);
	}
#endif

	datum = SysCacheGetAttr(PROCOID, tp, Anum_pg_proc_provolatile, &isnull);
	ReleaseSysCache(tp);

	return (DatumGetChar(datum) == PROVOLATILE_IMMUTABLE);
}

/*
 * GetForeignServer - look up the foreign server definition.
 */
ForeignServer *
GetForeignServer(Oid serverid)
{
	Form_pg_foreign_server serverform;
	ForeignServer *server;
	HeapTuple	tp;
	Datum		datum;
	bool		isnull;

	tp = SearchSysCache(FOREIGNSERVEROID,
						ObjectIdGetDatum(serverid),
						0, 0, 0);

	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for foreign server %u", serverid);

	serverform = (Form_pg_foreign_server) GETSTRUCT(tp);

	server = palloc(sizeof(ForeignServer));
	server->serverid = serverid;
	server->servername = pstrdup(NameStr(serverform->srvname));
	server->owner = serverform->srvowner;
	server->fdwid = serverform->srvfdw;

	/* Extract server type */
	datum = SysCacheGetAttr(FOREIGNSERVEROID,
							tp,
							Anum_pg_foreign_server_srvtype,
							&isnull);
	server->servertype = isnull ? NULL : pstrdup(TextDatumGetCString(datum));

	/* Extract server version */
	datum = SysCacheGetAttr(FOREIGNSERVEROID,
							tp,
							Anum_pg_foreign_server_srvversion,
							&isnull);
	server->serverversion = isnull ? NULL : pstrdup(TextDatumGetCString(datum));

	/* Extract the srvoptions */
	datum = SysCacheGetAttr(FOREIGNSERVEROID,
							tp,
							Anum_pg_foreign_server_srvoptions,
							&isnull);

	/* untransformRelOptions does exactly what we want - avoid duplication */
	server->options = untransformRelOptions(datum);

	ReleaseSysCache(tp);

	return server;
}

/*
 * Get state of subscription table.
 *
 * Returns SUBREL_STATE_UNKNOWN when not found and missing_ok is true.
 */
char
GetSubscriptionRelState(Oid subid, Oid relid, XLogRecPtr *sublsn,
						bool missing_ok)
{
	Relation	rel;
	HeapTuple	tup;
	char		substate;
	bool		isnull;
	Datum		d;

	rel = table_open(SubscriptionRelRelationId, AccessShareLock);

	/* Try finding the mapping. */
	tup = SearchSysCache2(SUBSCRIPTIONRELMAP,
						  ObjectIdGetDatum(relid),
						  ObjectIdGetDatum(subid));

	if (!HeapTupleIsValid(tup))
	{
		if (missing_ok)
		{
			table_close(rel, AccessShareLock);
			*sublsn = InvalidXLogRecPtr;
			return SUBREL_STATE_UNKNOWN;
		}

		elog(ERROR, "subscription table %u in subscription %u does not exist",
			 relid, subid);
	}

	/* Get the state. */
	d = SysCacheGetAttr(SUBSCRIPTIONRELMAP, tup,
						Anum_pg_subscription_rel_srsubstate, &isnull);
	Assert(!isnull);
	substate = DatumGetChar(d);
	d = SysCacheGetAttr(SUBSCRIPTIONRELMAP, tup,
						Anum_pg_subscription_rel_srsublsn, &isnull);
	if (isnull)
		*sublsn = InvalidXLogRecPtr;
	else
		*sublsn = DatumGetLSN(d);

	/* Cleanup */
	ReleaseSysCache(tup);
	table_close(rel, AccessShareLock);

	return substate;
}

/*
 * Fetch stored password for a user, for authentication.
 *
 * On error, returns NULL, and stores a palloc'd string describing the reason,
 * for the postmaster log, in *logdetail.  The error reason should *not* be
 * sent to the client, to avoid giving away user information!
 */
char *
get_role_password(const char *role, char **logdetail)
{
	TimestampTz vuntil = 0;
	HeapTuple	roleTup;
	Datum		datum;
	bool		isnull;
	char	   *shadow_pass;

	/* Get role info from pg_authid */
	roleTup = SearchSysCache1(AUTHNAME, PointerGetDatum(role));
	if (!HeapTupleIsValid(roleTup))
	{
		*logdetail = psprintf(_("Role \"%s\" does not exist."),
							  role);
		return NULL;			/* no such user */
	}

	datum = SysCacheGetAttr(AUTHNAME, roleTup,
							Anum_pg_authid_rolpassword, &isnull);
	if (isnull)
	{
		ReleaseSysCache(roleTup);
		*logdetail = psprintf(_("User \"%s\" has no password assigned."),
							  role);
		return NULL;			/* user has no password */
	}
	shadow_pass = TextDatumGetCString(datum);

	datum = SysCacheGetAttr(AUTHNAME, roleTup,
							Anum_pg_authid_rolvaliduntil, &isnull);
	if (!isnull)
		vuntil = DatumGetTimestampTz(datum);

	ReleaseSysCache(roleTup);

	/*
	 * Password OK, but check to be sure we are not past rolvaliduntil
	 */
	if (!isnull && vuntil < GetCurrentTimestamp())
	{
		*logdetail = psprintf(_("User \"%s\" has an expired password."),
							  role);
		return NULL;
	}

	return shadow_pass;
}

/*
 * Setup a ScanKey for a search in the relation 'rel' for a tuple 'key' that
 * is setup to match 'rel' (*NOT* idxrel!).
 *
 * Returns whether any column contains NULLs.
 *
 * This is not generic routine, it expects the idxrel to be replication
 * identity of a rel and meet all limitations associated with that.
 */
static bool
build_replindex_scan_key(ScanKey skey, Relation rel, Relation idxrel,
						 TupleTableSlot *searchslot)
{
	int			attoff;
	bool		isnull;
	Datum		indclassDatum;
	oidvector  *opclass;
	int2vector *indkey = &idxrel->rd_index->indkey;
	bool		hasnulls = false;

	Assert(RelationGetReplicaIndex(rel) == RelationGetRelid(idxrel));

	indclassDatum = SysCacheGetAttr(INDEXRELID, idxrel->rd_indextuple,
									Anum_pg_index_indclass, &isnull);
	Assert(!isnull);
	opclass = (oidvector *) DatumGetPointer(indclassDatum);

	/* Build scankey for every attribute in the index. */
	for (attoff = 0; attoff < IndexRelationGetNumberOfKeyAttributes(idxrel); attoff++)
	{
		Oid			operator;
		Oid			opfamily;
		RegProcedure regop;
		int			pkattno = attoff + 1;
		int			mainattno = indkey->values[attoff];
		Oid			optype = get_opclass_input_type(opclass->values[attoff]);

		/*
		 * Load the operator info.  We need this to get the equality operator
		 * function for the scan key.
		 */
		opfamily = get_opclass_family(opclass->values[attoff]);

		operator = get_opfamily_member(opfamily, optype,
									   optype,
									   BTEqualStrategyNumber);
		if (!OidIsValid(operator))
			elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
				 BTEqualStrategyNumber, optype, optype, opfamily);

		regop = get_opcode(operator);

		/* Initialize the scankey. */
		ScanKeyInit(&skey[attoff],
					pkattno,
					BTEqualStrategyNumber,
					regop,
					searchslot->tts_values[mainattno - 1]);

		/* Check for null value. */
		if (searchslot->tts_isnull[mainattno - 1])
		{
			hasnulls = true;
			skey[attoff].sk_flags |= SK_ISNULL;
		}
	}

	return hasnulls;
}

Datum
plhaskell_call_handler(PG_FUNCTION_ARGS)
{
    Oid fn_oid = fcinfo->flinfo->fn_oid;
    HeapTuple procTup = SearchSysCache1(PROCOID, ObjectIdGetDatum(fn_oid));

    bool isnull;
    Datum prosrcdatum = SysCacheGetAttr(PROCOID, procTup, Anum_pg_proc_prosrc, &isnull);
    if (isnull)
        elog(ERROR, "null prosrc");

	Form_pg_proc procStruct = (Form_pg_proc) GETSTRUCT(procTup);

    Oid *argTypes;
    char **argNames;
    char *argModes;
    int argCount = get_func_arg_info(procTup, &argTypes, &argNames, &argModes);

    Datum *datum = malloc(sizeof(Datum));

    int r = plhaskell_test(
        TextDatumGetCString(prosrcdatum),
        procStruct->prorettype,
        datum,
        argTypes,
        argCount,
        fcinfo->arg,
        sizeof(Datum)
    );

    if (r < 0)
      elog(ERROR, (const char *) (*datum));

    return *datum;
}

/*
 * Common code for properties that are just bit tests of indoptions.
 *
 * tuple: the pg_index heaptuple
 * attno: identify the index column to test the indoptions of.
 * guard: if false, a boolean false result is forced (saves code in caller).
 * iopt_mask: mask for interesting indoption bit.
 * iopt_expect: value for a "true" result (should be 0 or iopt_mask).
 *
 * Returns false to indicate a NULL result (for "unknown/inapplicable"),
 * otherwise sets *res to the boolean value to return.
 */
static bool
test_indoption(HeapTuple tuple, int attno, bool guard,
			   int16 iopt_mask, int16 iopt_expect,
			   bool *res)
{
	Datum		datum;
	bool		isnull;
	int2vector *indoption;
	int16		indoption_val;

	if (!guard)
	{
		*res = false;
		return true;
	}

	datum = SysCacheGetAttr(INDEXRELID, tuple,
							Anum_pg_index_indoption, &isnull);
	Assert(!isnull);

	indoption = ((int2vector *) DatumGetPointer(datum));
	indoption_val = indoption->values[attno - 1];

	*res = (indoption_val & iopt_mask) == iopt_expect;

	return true;
}

/*
 * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
 */
ForeignDataWrapper *
GetForeignDataWrapper(Oid fdwid)
{
	Form_pg_foreign_data_wrapper fdwform;
	ForeignDataWrapper *fdw;
	Datum		datum;
	HeapTuple	tp;
	bool		isnull;

	tp = SearchSysCache1(FOREIGNDATAWRAPPEROID, ObjectIdGetDatum(fdwid));

	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for foreign-data wrapper %u", fdwid);

	fdwform = (Form_pg_foreign_data_wrapper) GETSTRUCT(tp);

	fdw = palloc(sizeof(ForeignDataWrapper));
	fdw->fdwid = fdwid;
	fdw->owner = fdwform->fdwowner;
	fdw->fdwname = pstrdup(NameStr(fdwform->fdwname));
	fdw->fdwvalidator = fdwform->fdwvalidator;

	/* Extract the options */
	datum = SysCacheGetAttr(FOREIGNDATAWRAPPEROID,
							tp,
							Anum_pg_foreign_data_wrapper_fdwoptions,
							&isnull);
	fdw->options = untransformRelOptions(datum);

	ReleaseSysCache(tp);

	return fdw;
}

/*
 * GetForeignTable - look up the foreign table definition by relation oid.
 */
ForeignTable *
GetForeignTable(Oid relid)
{
	Form_pg_foreign_table tableform;
	ForeignTable *ft;
	HeapTuple	tp;
	Datum		datum;
	bool		isnull;

	tp = SearchSysCache1(FOREIGNTABLEREL, ObjectIdGetDatum(relid));
	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for foreign table %u", relid);
	tableform = (Form_pg_foreign_table) GETSTRUCT(tp);

	ft = (ForeignTable *) palloc(sizeof(ForeignTable));
	ft->relid = relid;
	ft->serverid = tableform->ftserver;

	/* Extract the ftoptions */
	datum = SysCacheGetAttr(FOREIGNTABLEREL,
							tp,
							Anum_pg_foreign_table_ftoptions,
							&isnull);
	if (isnull)
		ft->options = NIL;
	else
		ft->options = untransformRelOptions(datum);

	ReleaseSysCache(tp);

	return ft;
}

/*
 * statext_dependencies_load
 *		Load the functional dependencies for the indicated pg_statistic_ext tuple
 */
MVDependencies *
statext_dependencies_load(Oid mvoid)
{
	MVDependencies *result;
	bool		isnull;
	Datum		deps;
	HeapTuple	htup;

	htup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(mvoid));
	if (!HeapTupleIsValid(htup))
		elog(ERROR, "cache lookup failed for statistics object %u", mvoid);

	deps = SysCacheGetAttr(STATEXTOID, htup,
						   Anum_pg_statistic_ext_stxdependencies, &isnull);
	if (isnull)
		elog(ERROR,
			 "requested statistic kind \"%c\" is not yet built for statistics object %u",
			 STATS_EXT_DEPENDENCIES, mvoid);

	result = statext_dependencies_deserialize(DatumGetByteaPP(deps));

	ReleaseSysCache(htup);

	return result;
}

/*
 * GetForeignColumnOptions - Get attfdwoptions of given relation/attnum
 * as list of DefElem.
 */
List *
GetForeignColumnOptions(Oid relid, AttrNumber attnum)
{
	List	   *options;
	HeapTuple	tp;
	Datum		datum;
	bool		isnull;

	tp = SearchSysCache2(ATTNUM,
						 ObjectIdGetDatum(relid),
						 Int16GetDatum(attnum));
	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for attribute %d of relation %u",
			 attnum, relid);
	datum = SysCacheGetAttr(ATTNUM,
							tp,
							Anum_pg_attribute_attfdwoptions,
							&isnull);
	if (isnull)
		options = NIL;
	else
		options = untransformRelOptions(datum);

	ReleaseSysCache(tp);

	return options;
}

/*
 * statext_ndistinct_load
 *		Load the ndistinct value for the indicated pg_statistic_ext tuple
 */
MVNDistinct *
statext_ndistinct_load(Oid mvoid)
{
	MVNDistinct *result;
	bool		isnull;
	Datum		ndist;
	HeapTuple	htup;

	htup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(mvoid));
	if (!HeapTupleIsValid(htup))
		elog(ERROR, "cache lookup failed for statistics object %u", mvoid);

	ndist = SysCacheGetAttr(STATEXTOID, htup,
							Anum_pg_statistic_ext_stxndistinct, &isnull);
	if (isnull)
		elog(ERROR,
			 "requested statistic kind \"%c\" is not yet built for statistics object %u",
			 STATS_EXT_NDISTINCT, mvoid);

	result = statext_ndistinct_deserialize(DatumGetByteaPP(ndist));

	ReleaseSysCache(htup);

	return result;
}

/*
 * HeapTupleOfForeignConstraintIncludesColumn fetches the columns from the foreign
 * constraint and checks if the given column name matches one of them.
 */
static bool
HeapTupleOfForeignConstraintIncludesColumn(HeapTuple heapTuple, Oid relationId,
										   int pgConstraintKey, char *columnName)
{
	Datum columnsDatum = 0;
	Datum *columnArray = NULL;
	int columnCount = 0;
	int attrIdx = 0;
	bool isNull = false;

	columnsDatum = SysCacheGetAttr(CONSTROID, heapTuple, pgConstraintKey, &isNull);
	deconstruct_array(DatumGetArrayTypeP(columnsDatum), INT2OID, 2, true,
					  's', &columnArray, NULL, &columnCount);

	for (attrIdx = 0; attrIdx < columnCount; ++attrIdx)
	{
		AttrNumber attrNo = DatumGetInt16(columnArray[attrIdx]);

		char *colName = get_relid_attribute_name(relationId, attrNo);
		if (strncmp(colName, columnName, NAMEDATALEN) == 0)
		{
			return true;
		}
	}

	return false;
}

Datum
caql_getattr_internal(cqContext *pCtx, HeapTuple tup,
					  AttrNumber attnum, bool *isnull)
{
	if (pCtx->cq_usesyscache)
		return SysCacheGetAttr(pCtx->cq_cacheId, tup, attnum, isnull);
	else
		return heap_getattr(tup, attnum, pCtx->cq_tupdesc, isnull);
}

/*
 * Cache and return the procedure for the given strategy.
 */
FmgrInfo *
minmax_get_strategy_procinfo(BrinDesc *bdesc, uint16 attno, Oid subtype,
							 uint16 strategynum)
{
	MinmaxOpaque *opaque;

	Assert(strategynum >= 1 &&
		   strategynum <= BTMaxStrategyNumber);

	opaque = (MinmaxOpaque *) bdesc->bd_info[attno - 1]->oi_opaque;

	/*
	 * We cache the procedures for the previous subtype in the opaque struct,
	 * to avoid repetitive syscache lookups.  If the subtype changed,
	 * invalidate all the cached entries.
	 */
	if (opaque->cached_subtype != subtype)
	{
		uint16		i;

		for (i = 1; i <= BTMaxStrategyNumber; i++)
			opaque->strategy_procinfos[i - 1].fn_oid = InvalidOid;
		opaque->cached_subtype = subtype;
	}

	if (opaque->strategy_procinfos[strategynum - 1].fn_oid == InvalidOid)
	{
		Form_pg_attribute attr;
		HeapTuple	tuple;
		Oid			opfamily,
					oprid;
		bool		isNull;

		opfamily = bdesc->bd_index->rd_opfamily[attno - 1];
		attr = bdesc->bd_tupdesc->attrs[attno - 1];
		tuple = SearchSysCache4(AMOPSTRATEGY, ObjectIdGetDatum(opfamily),
								ObjectIdGetDatum(attr->atttypid),
								ObjectIdGetDatum(subtype),
								Int16GetDatum(strategynum));

		if (!HeapTupleIsValid(tuple))
			elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
				 strategynum, attr->atttypid, subtype, opfamily);

		oprid = DatumGetObjectId(SysCacheGetAttr(AMOPSTRATEGY, tuple,
												 Anum_pg_amop_amopopr, &isNull));
		ReleaseSysCache(tuple);
		Assert(!isNull && RegProcedureIsValid(oprid));

		fmgr_info_cxt(get_opcode(oprid),
					  &opaque->strategy_procinfos[strategynum - 1],
					  bdesc->bd_context);
	}

	return &opaque->strategy_procinfos[strategynum - 1];
}