*** pgsql/src/backend/utils/adt/dbsize.c	2010/01/23 21:29:00	1.28
--- pgsql/src/backend/utils/adt/dbsize.c	2010/02/07 20:48:10	1.29
***************
*** 1,11 ****
  /*
   * dbsize.c
!  *		object size functions
   *
   * Copyright (c) 2002-2010, PostgreSQL Global Development Group
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/adt/dbsize.c,v 1.27 2010/01/19 05:50:18 tgl Exp $
   *
   */
  
--- 1,11 ----
  /*
   * dbsize.c
!  *		Database object size functions, and related inquiries
   *
   * Copyright (c) 2002-2010, PostgreSQL Global Development Group
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/adt/dbsize.c,v 1.28 2010/01/23 21:29:00 tgl Exp $
   *
   */
  
***************
*** 25,30 ****
--- 25,31 ----
  #include "utils/acl.h"
  #include "utils/builtins.h"
  #include "utils/rel.h"
+ #include "utils/relmapper.h"
  #include "utils/syscache.h"
  
  
*************** pg_size_pretty(PG_FUNCTION_ARGS)
*** 507,509 ****
--- 508,628 ----
  
  	PG_RETURN_TEXT_P(cstring_to_text(buf));
  }
+ 
+ /*
+  * Get the filenode of a relation
+  *
+  * This is expected to be used in queries like
+  *		SELECT pg_relation_filenode(oid) FROM pg_class;
+  * That leads to a couple of choices.  We work from the pg_class row alone
+  * rather than actually opening each relation, for efficiency.  We don't
+  * fail if we can't find the relation --- some rows might be visible in
+  * the query's MVCC snapshot but already dead according to SnapshotNow.
+  * (Note: we could avoid using the catcache, but there's little point
+  * because the relation mapper also works "in the now".)  We also don't
+  * fail if the relation doesn't have storage.  In all these cases it
+  * seems better to quietly return NULL.
+  */
+ Datum
+ pg_relation_filenode(PG_FUNCTION_ARGS)
+ {
+ 	Oid			relid = PG_GETARG_OID(0);
+ 	Oid			result;
+ 	HeapTuple	tuple;
+ 	Form_pg_class relform;
+ 
+ 	tuple = SearchSysCache(RELOID,
+ 						   ObjectIdGetDatum(relid),
+ 						   0, 0, 0);
+ 	if (!HeapTupleIsValid(tuple))
+ 		PG_RETURN_NULL();
+ 	relform = (Form_pg_class) GETSTRUCT(tuple);
+ 
+ 	switch (relform->relkind)
+ 	{
+ 		case RELKIND_RELATION:
+ 		case RELKIND_INDEX:
+ 		case RELKIND_SEQUENCE:
+ 		case RELKIND_TOASTVALUE:
+ 			/* okay, these have storage */
+ 			if (relform->relfilenode)
+ 				result = relform->relfilenode;
+ 			else				/* Consult the relation mapper */
+ 				result = RelationMapOidToFilenode(relid,
+ 												  relform->relisshared);
+ 			break;
+ 
+ 		default:
+ 			/* no storage, return NULL */
+ 			result = InvalidOid;
+ 			break;
+ 	}
+ 
+ 	ReleaseSysCache(tuple);
+ 
+ 	if (!OidIsValid(result))
+ 		PG_RETURN_NULL();
+ 
+ 	PG_RETURN_OID(result);
+ }
+ 
+ /*
+  * Get the pathname (relative to $PGDATA) of a relation
+  *
+  * See comments for pg_relation_filenode.
+  */
+ Datum
+ pg_relation_filepath(PG_FUNCTION_ARGS)
+ {
+ 	Oid			relid = PG_GETARG_OID(0);
+ 	HeapTuple	tuple;
+ 	Form_pg_class relform;
+ 	RelFileNode rnode;
+ 	char	   *path;
+ 
+ 	tuple = SearchSysCache(RELOID,
+ 						   ObjectIdGetDatum(relid),
+ 						   0, 0, 0);
+ 	if (!HeapTupleIsValid(tuple))
+ 		PG_RETURN_NULL();
+ 	relform = (Form_pg_class) GETSTRUCT(tuple);
+ 
+ 	switch (relform->relkind)
+ 	{
+ 		case RELKIND_RELATION:
+ 		case RELKIND_INDEX:
+ 		case RELKIND_SEQUENCE:
+ 		case RELKIND_TOASTVALUE:
+ 			/* okay, these have storage */
+ 
+ 			/* This logic should match RelationInitPhysicalAddr */
+ 			if (relform->reltablespace)
+ 				rnode.spcNode = relform->reltablespace;
+ 			else
+ 				rnode.spcNode = MyDatabaseTableSpace;
+ 			if (rnode.spcNode == GLOBALTABLESPACE_OID)
+ 				rnode.dbNode = InvalidOid;
+ 			else
+ 				rnode.dbNode = MyDatabaseId;
+ 			if (relform->relfilenode)
+ 				rnode.relNode = relform->relfilenode;
+ 			else				/* Consult the relation mapper */
+ 				rnode.relNode = RelationMapOidToFilenode(relid,
+ 														 relform->relisshared);
+ 			break;
+ 
+ 		default:
+ 			/* no storage, return NULL */
+ 			rnode.relNode = InvalidOid;
+ 			break;
+ 	}
+ 
+ 	ReleaseSysCache(tuple);
+ 
+ 	if (!OidIsValid(rnode.relNode))
+ 		PG_RETURN_NULL();
+ 
+ 	path = relpath(rnode, MAIN_FORKNUM);
+ 
+ 	PG_RETURN_TEXT_P(cstring_to_text(path));
+ }