visibilitymap.h File Reference

#include "access/visibilitymapdefs.h"
#include "storage/block.h"
#include "storage/buf.h"
#include "storage/relfilelocator.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 (RelFileLocator rlocator, 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 (BlockNumber heapBlk, Buffer vmBuf, uint8 flags, RelFileLocator rlocator)
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)
BlockNumber	visibilitymap_truncation_length (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 ( RelFileLocator  rlocator, BlockNumber  heapBlk, Buffer  vmbuf, uint8  flags  )

extern

Definition at line 152 of file visibilitymap.c.

{
    int         mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
    int         mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
    BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
    uint8       mask = flags << mapOffset;
    Page        page;
    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",
         relpathbackend(rlocator, MyProcNumber, MAIN_FORKNUM).str,
         heapBlk);
#endif
 
    if (!BufferIsValid(vmbuf) || BufferGetBlockNumber(vmbuf) != mapBlock)
        elog(ERROR, "wrong buffer passed to visibilitymap_clear");
 
    Assert(BufferIsLockedByMeInMode(vmbuf, BUFFER_LOCK_EXCLUSIVE));
 
    page = BufferGetPage(vmbuf);
    map = PageGetContents(page);
 
    if (map[mapByte] & mask)
    {
        map[mapByte] &= ~mask;
 
        MarkBufferDirty(vmbuf);
        cleared = true;
    }
 
    return cleared;
}

References Assert, BUFFER_LOCK_EXCLUSIVE, BufferGetBlockNumber(), BufferGetPage(), BufferIsLockedByMeInMode(), BufferIsValid(), DEBUG1, elog, ERROR, fb(), HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, MAIN_FORKNUM, MarkBufferDirty(), MyProcNumber, PageGetContents(), relpathbackend, str, 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_page_fix_vm_corruption(), heap_update(), heap_xlog_update(), and heap_xlog_vm_clear().

visibilitymap_count()

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

extern

Definition at line 372 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(), fb(), FROZEN_MASK8, MAPSIZE, PageGetContents(), pg_popcount_masked(), ReleaseBuffer(), VISIBLE_MASK8, and vm_readbuf().

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

visibilitymap_get_status()

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

extern

Definition at line 324 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 (uint8) 0;
    }
 
    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, fb(), HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, InvalidBuffer, PageGetContents(), RelationGetRelationName, ReleaseBuffer(), result, VISIBILITYMAP_VALID_BITS, and vm_readbuf().

Referenced by collect_visibility_data(), find_next_unskippable_block(), heapcheck_read_stream_next_unskippable(), pg_visibility(), pg_visibility_map(), and prune_freeze_setup().

visibilitymap_pin()

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

extern

Definition at line 209 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(), fb(), HEAPBLK_TO_MAPBLOCK, ReleaseBuffer(), and vm_readbuf().

Referenced by GetVisibilityMapPins(), heap_delete(), heap_force_common(), heap_lock_tuple(), heap_lock_updated_tuple_rec(), heap_page_prune_opt(), heap_update(), lazy_scan_heap(), lazy_vacuum_heap_rel(), and RelationGetBufferForTuple().

visibilitymap_pin_ok()

bool visibilitymap_pin_ok ( BlockNumber  heapBlk, Buffer  vmbuf  )

extern

Definition at line 233 of file visibilitymap.c.

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

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

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

visibilitymap_prepare_truncate()

BlockNumber visibilitymap_prepare_truncate ( Relation  rel, BlockNumber  nheapblocks  )

extern

Definition at line 426 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, fb(), 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 ( BlockNumber  heapBlk, Buffer  vmBuf, uint8  flags, RelFileLocator  rlocator  )

extern

Definition at line 260 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;
    uint8       status;
 
#ifdef TRACE_VISIBILITYMAP
    elog(DEBUG1, "vm_set flags 0x%02X for %s %d",
         flags,
         relpathbackend(rlocator, MyProcNumber, MAIN_FORKNUM).str,
         heapBlk);
#endif
 
    /* Call in same critical section where WAL is emitted. */
    Assert(InRecovery || CritSectionCount > 0);
 
    /* Flags should be valid. Also never clear bits with this function */
    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 VM page pinned */
    if (!BufferIsValid(vmBuf) || BufferGetBlockNumber(vmBuf) != mapBlock)
        elog(ERROR, "wrong VM buffer passed to visibilitymap_set");
 
    Assert(BufferIsLockedByMeInMode(vmBuf, BUFFER_LOCK_EXCLUSIVE));
 
    page = BufferGetPage(vmBuf);
    map = (uint8 *) PageGetContents(page);
 
    status = (map[mapByte] >> mapOffset) & VISIBILITYMAP_VALID_BITS;
    if (flags != status)
    {
        map[mapByte] |= (flags << mapOffset);
        MarkBufferDirty(vmBuf);
    }
}

References Assert, BUFFER_LOCK_EXCLUSIVE, BufferGetBlockNumber(), BufferGetPage(), BufferIsLockedByMeInMode(), BufferIsValid(), CritSectionCount, DEBUG1, elog, ERROR, fb(), HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, InRecovery, MAIN_FORKNUM, MarkBufferDirty(), MyProcNumber, PageGetContents(), relpathbackend, str, VISIBILITYMAP_ALL_FROZEN, and VISIBILITYMAP_VALID_BITS.

Referenced by heap_multi_insert(), heap_page_prune_and_freeze(), heap_xlog_multi_insert(), heap_xlog_prune_freeze(), lazy_scan_new_or_empty(), and lazy_vacuum_heap_page().

visibilitymap_truncation_length()

BlockNumber visibilitymap_truncation_length ( BlockNumber  nheapblocks )

extern

Definition at line 529 of file visibilitymap.c.

{
    return HEAPBLK_TO_MAPBLOCK_LIMIT(nheapblocks);
}

References fb(), and HEAPBLK_TO_MAPBLOCK_LIMIT.

Referenced by SummarizeSmgrRecord().