visibilitymap.h File Reference

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

Include dependency graph for visibilitymap.h:

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Go to the source code of this file.

Macros
#define	BITS_PER_HEAPBLOCK   2
#define	VISIBILITYMAP_ALL_VISIBLE   0x01
#define	VISIBILITYMAP_ALL_FROZEN   0x02
#define	VISIBILITYMAP_VALID_BITS
#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)
void	visibilitymap_truncate (Relation rel, BlockNumber nheapblocks)

Macro Definition Documentation

#define BITS_PER_HEAPBLOCK   2

Definition at line 23 of file visibilitymap.h.

Referenced by rewriteVisibilityMap().

#define VISIBILITYMAP_ALL_FROZEN   0x02

Definition at line 27 of file visibilitymap.h.

Referenced by collect_visibility_data(), heap_lock_tuple(), heap_lock_updated_tuple_rec(), heap_update(), heap_xlog_lock(), heap_xlog_lock_updated(), lazy_scan_heap(), lazy_vacuum_page(), pg_visibility(), pg_visibility_map(), and pg_visibility_map_summary().

#define VISIBILITYMAP_ALL_VISIBLE   0x01

Definition at line 26 of file visibilitymap.h.

Referenced by collect_visibility_data(), lazy_scan_heap(), lazy_vacuum_page(), pg_visibility(), pg_visibility_map(), pg_visibility_map_summary(), and rewriteVisibilityMap().

#define VISIBILITYMAP_VALID_BITS

Value:

0x03    /* OR of all valid visibilitymap
                                             * flags bits */

Definition at line 28 of file visibilitymap.h.

Referenced by heap_delete(), heap_insert(), heap_multi_insert(), heap_update(), heap_xlog_delete(), heap_xlog_insert(), heap_xlog_multi_insert(), heap_xlog_update(), lazy_scan_heap(), visibilitymap_clear(), visibilitymap_get_status(), and visibilitymap_set().

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

Definition at line 34 of file visibilitymap.h.

Referenced by collect_corrupt_items(), and lazy_scan_heap().

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

Definition at line 32 of file visibilitymap.h.

Referenced by collect_corrupt_items(), IndexOnlyNext(), lazy_scan_heap(), and statapprox_heap().

Function Documentation

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

Definition at line 169 of file visibilitymap.c.

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, and VISIBILITYMAP_VALID_BITS.

Referenced by heap_delete(), 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_heap().

{
    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;

    Assert(flags & VISIBILITYMAP_VALID_BITS);

#ifdef TRACE_VISIBILITYMAP
    elog(DEBUG1, "vm_clear %s %d", RelationGetRelationName(rel), heapBlk);
#endif

    if (!BufferIsValid(buf) || BufferGetBlockNumber(buf) != mapBlock)
        elog(ERROR, "wrong buffer passed to visibilitymap_clear");

    LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
    map = PageGetContents(BufferGetPage(buf));

    if (map[mapByte] & mask)
    {
        map[mapByte] &= ~mask;

        MarkBufferDirty(buf);
        cleared = true;
    }

    LockBuffer(buf, BUFFER_LOCK_UNLOCK);

    return cleared;
}

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

Definition at line 408 of file visibilitymap.c.

References Assert, BufferGetPage, BufferIsValid, i, MAPSIZE, number_of_ones_for_frozen, number_of_ones_for_visible, PageGetContents, ReleaseBuffer(), and vm_readbuf().

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

{
    BlockNumber mapBlock;

    /* all_visible must be specified */
    Assert(all_visible);

    *all_visible = 0;
    if (all_frozen)
        *all_frozen = 0;

    for (mapBlock = 0;; mapBlock++)
    {
        Buffer      mapBuffer;
        unsigned char *map;
        int         i;

        /*
         * 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 = (unsigned char *) PageGetContents(BufferGetPage(mapBuffer));

        for (i = 0; i < MAPSIZE; i++)
        {
            *all_visible += number_of_ones_for_visible[map[i]];
            if (all_frozen)
                *all_frozen += number_of_ones_for_frozen[map[i]];
        }

        ReleaseBuffer(mapBuffer);
    }
}

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

Definition at line 360 of file visibilitymap.c.

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(), lazy_scan_heap(), lazy_vacuum_page(), pg_visibility(), pg_visibility_map(), and pg_visibility_map_summary().

{
    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(*buf))
    {
        if (BufferGetBlockNumber(*buf) != mapBlock)
        {
            ReleaseBuffer(*buf);
            *buf = InvalidBuffer;
        }
    }

    if (!BufferIsValid(*buf))
    {
        *buf = vm_readbuf(rel, mapBlock, false);
        if (!BufferIsValid(*buf))
            return false;
    }

    map = PageGetContents(BufferGetPage(*buf));

    /*
     * 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;
}

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

Definition at line 220 of file visibilitymap.c.

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

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

{
    BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);

    /* Reuse the old pinned buffer if possible */
    if (BufferIsValid(*buf))
    {
        if (BufferGetBlockNumber(*buf) == mapBlock)
            return;

        ReleaseBuffer(*buf);
    }
    *buf = vm_readbuf(rel, mapBlock, true);
}

bool visibilitymap_pin_ok	(	BlockNumber	heapBlk,
		Buffer	vmbuf
	)

Definition at line 244 of file visibilitymap.c.

References BufferGetBlockNumber(), BufferIsValid, and HEAPBLK_TO_MAPBLOCK.

Referenced by GetVisibilityMapPins().

{
    BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);

    return BufferIsValid(buf) && BufferGetBlockNumber(buf) == mapBlock;
}

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

Definition at line 273 of file visibilitymap.c.

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, RelationData::rd_node, RelationGetRelationName, RelationNeedsWAL, START_CRIT_SECTION, VISIBILITYMAP_VALID_BITS, XLogHintBitIsNeeded, and XLogRecPtrIsInvalid.

Referenced by heap_xlog_visible(), lazy_scan_heap(), and lazy_vacuum_page().

{
    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 || BufferIsValid(heapBuf));
    Assert(flags & VISIBILITYMAP_VALID_BITS);

    /* 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->rd_node, 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 (XLogHintBitIsNeeded())
                {
                    Page        heapPage = BufferGetPage(heapBuf);

                    /* caller is expected to set PD_ALL_VISIBLE first */
                    Assert(PageIsAllVisible(heapPage));
                    PageSetLSN(heapPage, recptr);
                }
            }
            PageSetLSN(page, recptr);
        }

        END_CRIT_SECTION();
    }

    LockBuffer(vmBuf, BUFFER_LOCK_UNLOCK);
}

void visibilitymap_truncate	(	Relation	rel,
		BlockNumber	nheapblocks
	)

Definition at line 462 of file visibilitymap.c.

References BUFFER_LOCK_EXCLUSIVE, BufferGetPage, BufferIsValid, DEBUG1, elog, END_CRIT_SECTION, HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, InRecovery, LockBuffer(), log_newpage_buffer(), MAPSIZE, MarkBufferDirty(), MemSet, PageGetContents, RelationData::rd_smgr, RelationGetRelationName, RelationNeedsWAL, RelationOpenSmgr, SMgrRelationData::smgr_vm_nblocks, smgrexists(), smgrnblocks(), smgrtruncate(), START_CRIT_SECTION, UnlockReleaseBuffer(), VISIBILITYMAP_FORKNUM, vm_readbuf(), and XLogHintBitIsNeeded.

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

{
    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

    RelationOpenSmgr(rel);

    /*
     * If no visibility map has been created yet for this relation, there's
     * nothing to truncate.
     */
    if (!smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
        return;

    /*
     * 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;
        }

        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(rel->rd_smgr, VISIBILITYMAP_FORKNUM) <= newnblocks)
    {
        /* nothing to do, the file was already smaller than requested size */
        return;
    }

    /* Truncate the unused VM pages, and send smgr inval message */
    smgrtruncate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, newnblocks);

    /*
     * We might as well update the local smgr_vm_nblocks setting. smgrtruncate
     * sent an smgr cache inval message, which will cause other backends to
     * invalidate their copy of smgr_vm_nblocks, and this one too at the next
     * command boundary.  But this ensures it isn't outright wrong until then.
     */
    if (rel->rd_smgr)
        rel->rd_smgr->smgr_vm_nblocks = newnblocks;
}