1 /*-------------------------------------------------------------------------
4 * POSTGRES free space map for quickly finding free pages in relations
7 * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
11 * src/backend/storage/freespace/indexfsm.c
16 * This is similar to the FSM used for heap, in freespace.c, but instead
17 * of tracking the amount of free space on pages, we only track whether
18 * pages are completely free or in-use. We use the same FSM implementation
19 * as for heaps, using BLCKSZ - 1 to denote used pages, and 0 for unused.
21 *-------------------------------------------------------------------------
25 #include "storage/freespace.h"
26 #include "storage/indexfsm.h"
27 #include "storage/smgr.h"
34 * GetFreeIndexPage - return a free page from the FSM
36 * As a side effect, the page is marked as used in the FSM.
39 GetFreeIndexPage(Relation rel)
41 BlockNumber blkno = GetPageWithFreeSpace(rel, BLCKSZ / 2);
43 if (blkno != InvalidBlockNumber)
44 RecordUsedIndexPage(rel, blkno);
50 * RecordFreeIndexPage - mark a page as free in the FSM
53 RecordFreeIndexPage(Relation rel, BlockNumber freeBlock)
55 RecordPageWithFreeSpace(rel, freeBlock, BLCKSZ - 1);
60 * RecordUsedIndexPage - mark a page as used in the FSM
63 RecordUsedIndexPage(Relation rel, BlockNumber usedBlock)
65 RecordPageWithFreeSpace(rel, usedBlock, 0);
69 * IndexFreeSpaceMapVacuum - scan and fix any inconsistencies in the FSM
72 IndexFreeSpaceMapVacuum(Relation rel)
74 FreeSpaceMapVacuum(rel);