inv_api.c

关系型数据库 Postgresql 6.5.2

/*-------------------------------------------------------------------------
 *
 * inv_api.c
 *	  routines for manipulating inversion fs large objects. This file
 *	  contains the user-level large object application interface routines.
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /usr/local/cvsroot/pgsql/src/backend/storage/large_object/inv_api.c,v 1.53 1999/05/25 16:11:15 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include <sys/types.h>
#include <stdio.h>				/* for sprintf() */
#include <string.h>
#include <sys/file.h>
#include <sys/stat.h>

#include "postgres.h"

#include "access/genam.h"
#include "access/heapam.h"
#include "access/relscan.h"
#include "access/tupdesc.h"
#include "access/transam.h"
#include "access/xact.h"
#include "access/nbtree.h"
#include "access/tupdesc.h"
#include "catalog/catalog.h"	/* for newoid() */
#include "catalog/heap.h"
#include "catalog/index.h"		/* for index_create() */
#include "catalog/pg_am.h"		/* for BTREE_AM_OID */
#include "catalog/pg_type.h"	/* for INT4OID */
#include "catalog/pg_opclass.h" /* for INT4_OPS_OID */
#include "fmgr.h"
#include "libpq/libpq-fs.h"
#include "miscadmin.h"
#include "nodes/pg_list.h"
#include "storage/itemptr.h"
#include "storage/bufpage.h"
#include "storage/bufmgr.h"
#include "storage/large_object.h"
#include "storage/lmgr.h"
#include "storage/smgr.h"
#include "utils/builtins.h"		/* for namestrcpy() */
#include "utils/rel.h"
#include "utils/relcache.h"

/*
 *	Warning, Will Robinson...  In order to pack data into an inversion
 *	file as densely as possible, we violate the class abstraction here.
 *	When we're appending a new tuple to the end of the table, we check
 *	the last page to see how much data we can put on it.  If it's more
 *	than IMINBLK, we write enough to fill the page.  This limits external
 *	fragmentation.	In no case can we write more than IMAXBLK, since
 *	the 8K postgres page size less overhead leaves only this much space
 *	for data.
 */

/*
 *		In order to prevent buffer leak on transaction commit, large object
 *		scan index handling has been modified. Indexes are persistant inside
 *		a transaction but may be closed between two calls to this API (when
 *		transaction is committed while object is opened, or when no
 *		transaction is active). Scan indexes are thus now reinitialized using
 *		the object current offset. [PA]
 *
 *		Some cleanup has been also done for non freed memory.
 *
 *		For subsequent notes, [PA] is Pascal Andr