visibilitymap.h File Reference

#include "access/visibilitymapdefs.h"
#include "access/xlogdefs.h"
#include "storage/block.h"
#include "storage/buf.h"
#include "utils/relcache.h"

Include dependency graph for visibilitymap.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	VM_ALL_VISIBLE(r, b, v)    ((visibilitymap_get_status((r), (b), (v)) & VISIBILITYMAP_ALL_VISIBLE) != 0)
#define	VM_ALL_FROZEN(r, b, v)    ((visibilitymap_get_status((r), (b), (v)) & VISIBILITYMAP_ALL_FROZEN) != 0)

Functions
bool	visibilitymap_clear (Relation rel, BlockNumber heapBlk, Buffer vmbuf, uint8 flags)
void	visibilitymap_pin (Relation rel, BlockNumber heapBlk, Buffer *vmbuf)
bool	visibilitymap_pin_ok (BlockNumber heapBlk, Buffer vmbuf)
void	visibilitymap_set (Relation rel, BlockNumber heapBlk, Buffer heapBuf, XLogRecPtr recptr, Buffer vmBuf, TransactionId cutoff_xid, uint8 flags)
uint8	visibilitymap_get_status (Relation rel, BlockNumber heapBlk, Buffer *vmbuf)
void	visibilitymap_count (Relation rel, BlockNumber *all_visible, BlockNumber *all_frozen)
BlockNumber	visibilitymap_prepare_truncate (Relation rel, BlockNumber nheapblocks)

Macro Definition Documentation

VM_ALL_FROZEN

#define VM_ALL_FROZEN	(		r,
			b,
			v
	)		((visibilitymap_get_status((r), (b), (v)) & VISIBILITYMAP_ALL_FROZEN) != 0)

Definition at line 26 of file visibilitymap.h.

VM_ALL_VISIBLE

#define VM_ALL_VISIBLE	(		r,
			b,
			v
	)		((visibilitymap_get_status((r), (b), (v)) & VISIBILITYMAP_ALL_VISIBLE) != 0)

Definition at line 24 of file visibilitymap.h.

Function Documentation

visibilitymap_clear()

bool visibilitymap_clear	(	Relation	rel,
		BlockNumber	heapBlk,
		Buffer	vmbuf,
		uint8	flags
	)

Definition at line 138 of file visibilitymap.c.

{
    BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
    int         mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
    int         mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
    uint8       mask = flags << mapOffset;
    char       *map;
    bool        cleared = false;
 
    /* Must never clear all_visible bit while leaving all_frozen bit set */
    Assert(flags & VISIBILITYMAP_VALID_BITS);
    Assert(flags != VISIBILITYMAP_ALL_VISIBLE);
 
#ifdef TRACE_VISIBILITYMAP
    elog(DEBUG1, "vm_clear %s %d", RelationGetRelationName(rel), heapBlk);
#endif
 
    if (!BufferIsValid(vmbuf) || BufferGetBlockNumber(vmbuf) != mapBlock)
        elog(ERROR, "wrong buffer passed to visibilitymap_clear");
 
    LockBuffer(vmbuf, BUFFER_LOCK_EXCLUSIVE);
    map = PageGetContents(BufferGetPage(vmbuf));
 
    if (map[mapByte] & mask)
    {
        map[mapByte] &= ~mask;
 
        MarkBufferDirty(vmbuf);
        cleared = true;
    }
 
    LockBuffer(vmbuf, BUFFER_LOCK_UNLOCK);
 
    return cleared;
}

References Assert, BUFFER_LOCK_EXCLUSIVE, BUFFER_LOCK_UNLOCK, BufferGetBlockNumber(), BufferGetPage(), BufferIsValid(), DEBUG1, elog, ERROR, HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, LockBuffer(), MarkBufferDirty(), PageGetContents(), RelationGetRelationName, VISIBILITYMAP_ALL_VISIBLE, and VISIBILITYMAP_VALID_BITS.

Referenced by heap_delete(), heap_force_common(), heap_insert(), heap_lock_tuple(), heap_lock_updated_tuple_rec(), heap_multi_insert(), heap_update(), heap_xlog_delete(), heap_xlog_insert(), heap_xlog_lock(), heap_xlog_lock_updated(), heap_xlog_multi_insert(), heap_xlog_update(), and lazy_scan_prune().

visibilitymap_count()

void visibilitymap_count	(	Relation	rel,
		BlockNumber *	all_visible,
		BlockNumber *	all_frozen
	)

Definition at line 384 of file visibilitymap.c.

{
    BlockNumber mapBlock;
    BlockNumber nvisible = 0;
    BlockNumber nfrozen = 0;
 
    /* all_visible must be specified */
    Assert(all_visible);
 
    for (mapBlock = 0;; mapBlock++)
    {
        Buffer      mapBuffer;
        uint64     *map;
 
        /*
         * Read till we fall off the end of the map.  We assume that any extra
         * bytes in the last page are zeroed, so we don't bother excluding
         * them from the count.
         */
        mapBuffer = vm_readbuf(rel, mapBlock, false);
        if (!BufferIsValid(mapBuffer))
            break;
 
        /*
         * We choose not to lock the page, since the result is going to be
         * immediately stale anyway if anyone is concurrently setting or
         * clearing bits, and we only really need an approximate value.
         */
        map = (uint64 *) PageGetContents(BufferGetPage(mapBuffer));
 
        nvisible += pg_popcount_masked((const char *) map, MAPSIZE, VISIBLE_MASK8);
        if (all_frozen)
            nfrozen += pg_popcount_masked((const char *) map, MAPSIZE, FROZEN_MASK8);
 
        ReleaseBuffer(mapBuffer);
    }
 
    *all_visible = nvisible;
    if (all_frozen)
        *all_frozen = nfrozen;
}

References Assert, BufferGetPage(), BufferIsValid(), FROZEN_MASK8, MAPSIZE, PageGetContents(), pg_popcount_masked(), ReleaseBuffer(), VISIBLE_MASK8, and vm_readbuf().

Referenced by do_analyze_rel(), heap_vacuum_rel(), and index_update_stats().

visibilitymap_get_status()

uint8 visibilitymap_get_status	(	Relation	rel,
		BlockNumber	heapBlk,
		Buffer *	vmbuf
	)

Definition at line 336 of file visibilitymap.c.

{
    BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
    uint32      mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
    uint8       mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
    char       *map;
    uint8       result;
 
#ifdef TRACE_VISIBILITYMAP
    elog(DEBUG1, "vm_get_status %s %d", RelationGetRelationName(rel), heapBlk);
#endif
 
    /* Reuse the old pinned buffer if possible */
    if (BufferIsValid(*vmbuf))
    {
        if (BufferGetBlockNumber(*vmbuf) != mapBlock)
        {
            ReleaseBuffer(*vmbuf);
            *vmbuf = InvalidBuffer;
        }
    }
 
    if (!BufferIsValid(*vmbuf))
    {
        *vmbuf = vm_readbuf(rel, mapBlock, false);
        if (!BufferIsValid(*vmbuf))
            return false;
    }
 
    map = PageGetContents(BufferGetPage(*vmbuf));
 
    /*
     * A single byte read is atomic.  There could be memory-ordering effects
     * here, but for performance reasons we make it the caller's job to worry
     * about that.
     */
    result = ((map[mapByte] >> mapOffset) & VISIBILITYMAP_VALID_BITS);
    return result;
}

References BufferGetBlockNumber(), BufferGetPage(), BufferIsValid(), DEBUG1, elog, HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, InvalidBuffer, PageGetContents(), RelationGetRelationName, ReleaseBuffer(), VISIBILITYMAP_VALID_BITS, and vm_readbuf().

Referenced by collect_visibility_data(), find_next_unskippable_block(), lazy_scan_prune(), pg_visibility(), pg_visibility_map(), pg_visibility_map_summary(), and verify_heapam().

visibilitymap_pin()

void visibilitymap_pin	(	Relation	rel,
		BlockNumber	heapBlk,
		Buffer *	vmbuf
	)

Definition at line 191 of file visibilitymap.c.

{
    BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
 
    /* Reuse the old pinned buffer if possible */
    if (BufferIsValid(*vmbuf))
    {
        if (BufferGetBlockNumber(*vmbuf) == mapBlock)
            return;
 
        ReleaseBuffer(*vmbuf);
    }
    *vmbuf = vm_readbuf(rel, mapBlock, true);
}

References BufferGetBlockNumber(), BufferIsValid(), HEAPBLK_TO_MAPBLOCK, ReleaseBuffer(), and vm_readbuf().

Referenced by GetVisibilityMapPins(), heap_delete(), heap_force_common(), heap_lock_tuple(), heap_lock_updated_tuple_rec(), heap_update(), heap_xlog_delete(), heap_xlog_insert(), heap_xlog_lock(), heap_xlog_lock_updated(), heap_xlog_multi_insert(), heap_xlog_update(), heap_xlog_visible(), lazy_scan_heap(), lazy_vacuum_heap_rel(), and RelationGetBufferForTuple().

visibilitymap_pin_ok()

bool visibilitymap_pin_ok	(	BlockNumber	heapBlk,
		Buffer	vmbuf
	)

Definition at line 215 of file visibilitymap.c.

{
    BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
 
    return BufferIsValid(vmbuf) && BufferGetBlockNumber(vmbuf) == mapBlock;
}

References BufferGetBlockNumber(), BufferIsValid(), and HEAPBLK_TO_MAPBLOCK.

Referenced by GetVisibilityMapPins(), heap_multi_insert(), and RelationGetBufferForTuple().

visibilitymap_prepare_truncate()

BlockNumber visibilitymap_prepare_truncate	(	Relation	rel,
		BlockNumber	nheapblocks
	)

Definition at line 438 of file visibilitymap.c.

{
    BlockNumber newnblocks;
 
    /* last remaining block, byte, and bit */
    BlockNumber truncBlock = HEAPBLK_TO_MAPBLOCK(nheapblocks);
    uint32      truncByte = HEAPBLK_TO_MAPBYTE(nheapblocks);
    uint8       truncOffset = HEAPBLK_TO_OFFSET(nheapblocks);
 
#ifdef TRACE_VISIBILITYMAP
    elog(DEBUG1, "vm_truncate %s %d", RelationGetRelationName(rel), nheapblocks);
#endif
 
    /*
     * If no visibility map has been created yet for this relation, there's
     * nothing to truncate.
     */
    if (!smgrexists(RelationGetSmgr(rel), VISIBILITYMAP_FORKNUM))
        return InvalidBlockNumber;
 
    /*
     * Unless the new size is exactly at a visibility map page boundary, the
     * tail bits in the last remaining map page, representing truncated heap
     * blocks, need to be cleared. This is not only tidy, but also necessary
     * because we don't get a chance to clear the bits if the heap is extended
     * again.
     */
    if (truncByte != 0 || truncOffset != 0)
    {
        Buffer      mapBuffer;
        Page        page;
        char       *map;
 
        newnblocks = truncBlock + 1;
 
        mapBuffer = vm_readbuf(rel, truncBlock, false);
        if (!BufferIsValid(mapBuffer))
        {
            /* nothing to do, the file was already smaller */
            return InvalidBlockNumber;
        }
 
        page = BufferGetPage(mapBuffer);
        map = PageGetContents(page);
 
        LockBuffer(mapBuffer, BUFFER_LOCK_EXCLUSIVE);
 
        /* NO EREPORT(ERROR) from here till changes are logged */
        START_CRIT_SECTION();
 
        /* Clear out the unwanted bytes. */
        MemSet(&map[truncByte + 1], 0, MAPSIZE - (truncByte + 1));
 
        /*----
         * Mask out the unwanted bits of the last remaining byte.
         *
         * ((1 << 0) - 1) = 00000000
         * ((1 << 1) - 1) = 00000001
         * ...
         * ((1 << 6) - 1) = 00111111
         * ((1 << 7) - 1) = 01111111
         *----
         */
        map[truncByte] &= (1 << truncOffset) - 1;
 
        /*
         * Truncation of a relation is WAL-logged at a higher-level, and we
         * will be called at WAL replay. But if checksums are enabled, we need
         * to still write a WAL record to protect against a torn page, if the
         * page is flushed to disk before the truncation WAL record. We cannot
         * use MarkBufferDirtyHint here, because that will not dirty the page
         * during recovery.
         */
        MarkBufferDirty(mapBuffer);
        if (!InRecovery && RelationNeedsWAL(rel) && XLogHintBitIsNeeded())
            log_newpage_buffer(mapBuffer, false);
 
        END_CRIT_SECTION();
 
        UnlockReleaseBuffer(mapBuffer);
    }
    else
        newnblocks = truncBlock;
 
    if (smgrnblocks(RelationGetSmgr(rel), VISIBILITYMAP_FORKNUM) <= newnblocks)
    {
        /* nothing to do, the file was already smaller than requested size */
        return InvalidBlockNumber;
    }
 
    return newnblocks;
}

References BUFFER_LOCK_EXCLUSIVE, BufferGetPage(), BufferIsValid(), DEBUG1, elog, END_CRIT_SECTION, HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, InRecovery, InvalidBlockNumber, LockBuffer(), log_newpage_buffer(), MAPSIZE, MarkBufferDirty(), MemSet, PageGetContents(), RelationGetRelationName, RelationGetSmgr(), RelationNeedsWAL, smgrexists(), smgrnblocks(), START_CRIT_SECTION, UnlockReleaseBuffer(), VISIBILITYMAP_FORKNUM, vm_readbuf(), and XLogHintBitIsNeeded.

Referenced by pg_truncate_visibility_map(), RelationTruncate(), and smgr_redo().

visibilitymap_set()

void visibilitymap_set	(	Relation	rel,
		BlockNumber	heapBlk,
		Buffer	heapBuf,
		XLogRecPtr	recptr,
		Buffer	vmBuf,
		TransactionId	cutoff_xid,
		uint8	flags
	)

Definition at line 244 of file visibilitymap.c.

{
    BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
    uint32      mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
    uint8       mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
    Page        page;
    uint8      *map;
 
#ifdef TRACE_VISIBILITYMAP
    elog(DEBUG1, "vm_set %s %d", RelationGetRelationName(rel), heapBlk);
#endif
 
    Assert(InRecovery || XLogRecPtrIsInvalid(recptr));
    Assert(InRecovery || PageIsAllVisible((Page) BufferGetPage(heapBuf)));
    Assert((flags & VISIBILITYMAP_VALID_BITS) == flags);
 
    /* Must never set all_frozen bit without also setting all_visible bit */
    Assert(flags != VISIBILITYMAP_ALL_FROZEN);
 
    /* Check that we have the right heap page pinned, if present */
    if (BufferIsValid(heapBuf) && BufferGetBlockNumber(heapBuf) != heapBlk)
        elog(ERROR, "wrong heap buffer passed to visibilitymap_set");
 
    /* Check that we have the right VM page pinned */
    if (!BufferIsValid(vmBuf) || BufferGetBlockNumber(vmBuf) != mapBlock)
        elog(ERROR, "wrong VM buffer passed to visibilitymap_set");
 
    page = BufferGetPage(vmBuf);
    map = (uint8 *) PageGetContents(page);
    LockBuffer(vmBuf, BUFFER_LOCK_EXCLUSIVE);
 
    if (flags != (map[mapByte] >> mapOffset & VISIBILITYMAP_VALID_BITS))
    {
        START_CRIT_SECTION();
 
        map[mapByte] |= (flags << mapOffset);
        MarkBufferDirty(vmBuf);
 
        if (RelationNeedsWAL(rel))
        {
            if (XLogRecPtrIsInvalid(recptr))
            {
                Assert(!InRecovery);
                recptr = log_heap_visible(rel, heapBuf, vmBuf, cutoff_xid, flags);
 
                /*
                 * If data checksums are enabled (or wal_log_hints=on), we
                 * need to protect the heap page from being torn.
                 *
                 * If not, then we must *not* update the heap page's LSN. In
                 * this case, the FPI for the heap page was omitted from the
                 * WAL record inserted above, so it would be incorrect to
                 * update the heap page's LSN.
                 */
                if (XLogHintBitIsNeeded())
                {
                    Page        heapPage = BufferGetPage(heapBuf);
 
                    PageSetLSN(heapPage, recptr);
                }
            }
            PageSetLSN(page, recptr);
        }
 
        END_CRIT_SECTION();
    }
 
    LockBuffer(vmBuf, BUFFER_LOCK_UNLOCK);
}

References Assert, BUFFER_LOCK_EXCLUSIVE, BUFFER_LOCK_UNLOCK, BufferGetBlockNumber(), BufferGetPage(), BufferIsValid(), DEBUG1, elog, END_CRIT_SECTION, ERROR, HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, InRecovery, LockBuffer(), log_heap_visible(), MarkBufferDirty(), PageGetContents(), PageIsAllVisible(), PageSetLSN(), RelationGetRelationName, RelationNeedsWAL, START_CRIT_SECTION, VISIBILITYMAP_ALL_FROZEN, VISIBILITYMAP_VALID_BITS, XLogHintBitIsNeeded, and XLogRecPtrIsInvalid.

Referenced by heap_multi_insert(), heap_xlog_visible(), lazy_scan_new_or_empty(), lazy_scan_prune(), and lazy_vacuum_heap_page().