Postgresql快速查询对象OID：pg_get_object_address

pg_describe_object(PG_FUNCTION_ARGS)
{
	Oid			classid = PG_GETARG_OID(0);
	Oid			objid = PG_GETARG_OID(1);
	int32		objsubid = PG_GETARG_INT32(2);
	...

-- 2615: pg_namespace(from pg_class)
-- 2200: public(from pg_namespace)
postgres=# SELECT pg_get_object_address('schema', '{public}', '{t1}');
 pg_get_object_address 
-----------------------
 (2615,2200,0)


-- 1259: pg_class(from pg_class)
-- 16398: t1(from pg_class)
SELECT pg_get_object_address('table', '{t1}', '{}');
 pg_get_object_address 
-----------------------
 (1259,16398,0)

// 参数1用ObjectTypeMap做字符串匹配
pg_get_object_address
	char	   *ttype = TextDatumGetCString(PG_GETARG_DATUM(0));
		itype = read_objtype_from_string(ttype);
			if (strcmp(ObjectTypeMap[i].tm_name, objtype) == 0)


ObjectTypeMap[] =
{
	/* OCLASS_CLASS, all kinds of relations */
	{
		"table", OBJECT_TABLE
	},
	{
		"index", OBJECT_INDEX
	},
	{
		"sequence", OBJECT_SEQUENCE
	},
	{
		"toast table", -1
	},							/* unmapped */
	{
		"view", OBJECT_VIEW
	},
	{
		"materialized view", OBJECT_MATVIEW
	},
	{
		"composite type", -1
	},							/* unmapped */
	{
		"foreign table", OBJECT_FOREIGN_TABLE
	},
	{
		"table column", OBJECT_COLUMN
	},
	{
		"index column", -1
	},							/* unmapped */
	{
		"sequence column", -1
	},							/* unmapped */
	{
		"toast table column", -1
	},							/* unmapped */
	{
		"view column", -1
	},							/* unmapped */
	{
		"materialized view column", -1
	},							/* unmapped */
	{
		"composite type column", -1
	},							/* unmapped */
	{
		"foreign table column", OBJECT_COLUMN
	},
	/* OCLASS_PROC */
	{
		"aggregate", OBJECT_AGGREGATE
	},
	{
		"function", OBJECT_FUNCTION
	},
	{
		"procedure", OBJECT_PROCEDURE
	},
	/* OCLASS_TYPE */
	{
		"type", OBJECT_TYPE
	},
	/* OCLASS_CAST */
	{
		"cast", OBJECT_CAST
	},
	/* OCLASS_COLLATION */
	{
		"collation", OBJECT_COLLATION
	},
	/* OCLASS_CONSTRAINT */
	{
		"table constraint", OBJECT_TABCONSTRAINT
	},
	{
		"domain constraint", OBJECT_DOMCONSTRAINT
	},
	/* OCLASS_CONVERSION */
	{
		"conversion", OBJECT_CONVERSION
	},
	/* OCLASS_DEFAULT */
	{
		"default value", OBJECT_DEFAULT
	},
	/* OCLASS_LANGUAGE */
	{
		"language", OBJECT_LANGUAGE
	},
	/* OCLASS_LARGEOBJECT */
	{
		"large object", OBJECT_LARGEOBJECT
	},
	/* OCLASS_OPERATOR */
	{
		"operator", OBJECT_OPERATOR
	},
	/* OCLASS_OPCLASS */
	{
		"operator class", OBJECT_OPCLASS
	},
	/* OCLASS_OPFAMILY */
	{
		"operator family", OBJECT_OPFAMILY
	},
	/* OCLASS_AM */
	{
		"access method", OBJECT_ACCESS_METHOD
	},
	/* OCLASS_AMOP */
	{
		"operator of access method", OBJECT_AMOP
	},
	/* OCLASS_AMPROC */
	{
		"function of access method", OBJECT_AMPROC
	},
	/* OCLASS_REWRITE */
	{
		"rule", OBJECT_RULE
	},
	/* OCLASS_TRIGGER */
	{
		"trigger", OBJECT_TRIGGER
	},
	/* OCLASS_SCHEMA */
	{
		"schema", OBJECT_SCHEMA
	},
	/* OCLASS_TSPARSER */
	{
		"text search parser", OBJECT_TSPARSER
	},
	/* OCLASS_TSDICT */
	{
		"text search dictionary", OBJECT_TSDICTIONARY
	},
	/* OCLASS_TSTEMPLATE */
	{
		"text search template", OBJECT_TSTEMPLATE
	},
	/* OCLASS_TSCONFIG */
	{
		"text search configuration", OBJECT_TSCONFIGURATION
	},
	/* OCLASS_ROLE */
	{
		"role", OBJECT_ROLE
	},
	/* OCLASS_DATABASE */
	{
		"database", OBJECT_DATABASE
	},
	/* OCLASS_TBLSPACE */
	{
		"tablespace", OBJECT_TABLESPACE
	},
	/* OCLASS_FDW */
	{
		"foreign-data wrapper", OBJECT_FDW
	},
	/* OCLASS_FOREIGN_SERVER */
	{
		"server", OBJECT_FOREIGN_SERVER
	},
	/* OCLASS_USER_MAPPING */
	{
		"user mapping", OBJECT_USER_MAPPING
	},
	/* OCLASS_DEFACL */
	{
		"default acl", OBJECT_DEFACL
	},
	/* OCLASS_EXTENSION */
	{
		"extension", OBJECT_EXTENSION
	},
	/* OCLASS_EVENT_TRIGGER */
	{
		"event trigger", OBJECT_EVENT_TRIGGER
	},
	/* OCLASS_POLICY */
	{
		"policy", OBJECT_POLICY
	},
	/* OCLASS_PUBLICATION */
	{
		"publication", OBJECT_PUBLICATION
	},
	/* OCLASS_PUBLICATION_REL */
	{
		"publication relation", OBJECT_PUBLICATION_REL
	},
	/* OCLASS_SUBSCRIPTION */
	{
		"subscription", OBJECT_SUBSCRIPTION
	},
	/* OCLASS_TRANSFORM */
	{
		"transform", OBJECT_TRANSFORM
	},
	/* OCLASS_STATISTIC_EXT */
	{
		"statistics object", OBJECT_STATISTIC_EXT
	}
};