* is set, we know the condition is true, but if a bit is not set, it might or
* might not be true.
*
- * Clearing both visibility map bits is not separately WAL-logged. The callers
+ * Clearing visibility map bits is not separately WAL-logged. The callers
* must make sure that whenever a bit is cleared, the bit is cleared on WAL
* replay of the updating operation as well.
*
*/
#define MAPSIZE (BLCKSZ - MAXALIGN(SizeOfPageHeaderData))
+/* Number of heap blocks we can represent in one byte */
+#define HEAPBLOCKS_PER_BYTE (BITS_PER_BYTE / BITS_PER_HEAPBLOCK)
+
/* Number of heap blocks we can represent in one visibility map page. */
#define HEAPBLOCKS_PER_PAGE (MAPSIZE * HEAPBLOCKS_PER_BYTE)
/* Mapping from heap block number to the right bit in the visibility map */
#define HEAPBLK_TO_MAPBLOCK(x) ((x) / HEAPBLOCKS_PER_PAGE)
#define HEAPBLK_TO_MAPBYTE(x) (((x) % HEAPBLOCKS_PER_PAGE) / HEAPBLOCKS_PER_BYTE)
-#define HEAPBLK_TO_MAPBIT(x) (((x) % HEAPBLOCKS_PER_BYTE) * BITS_PER_HEAPBLOCK)
+#define HEAPBLK_TO_OFFSET(x) (((x) % HEAPBLOCKS_PER_BYTE) * BITS_PER_HEAPBLOCK)
/* tables for fast counting of set bits for visible and frozen */
static const uint8 number_of_ones_for_visible[256] = {
/*
- * visibilitymap_clear - clear all bits in visibility map
+ * visibilitymap_clear - clear all bits for one page in visibility map
*
* You must pass a buffer containing the correct map page to this function.
* Call visibilitymap_pin first to pin the right one. This function doesn't do
{
BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
int mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
- int mapBit = HEAPBLK_TO_MAPBIT(heapBlk);
- uint8 mask = VISIBILITYMAP_VALID_BITS << mapBit;
+ int mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
+ uint8 mask = VISIBILITYMAP_VALID_BITS << mapOffset;
char *map;
#ifdef TRACE_VISIBILITYMAP
{
BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
uint32 mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
- uint8 mapBit = HEAPBLK_TO_MAPBIT(heapBlk);
+ uint8 mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
Page page;
uint8 *map;
map = (uint8 *)PageGetContents(page);
LockBuffer(vmBuf, BUFFER_LOCK_EXCLUSIVE);
- if (flags != (map[mapByte] >> mapBit & VISIBILITYMAP_VALID_BITS))
+ if (flags != (map[mapByte] >> mapOffset & VISIBILITYMAP_VALID_BITS))
{
START_CRIT_SECTION();
- map[mapByte] |= (flags << mapBit);
+ map[mapByte] |= (flags << mapOffset);
MarkBufferDirty(vmBuf);
if (RelationNeedsWAL(rel))
* earlier call to visibilitymap_pin or visibilitymap_get_status on the same
* relation. On return, *buf is a valid buffer with the map page containing
* the bit for heapBlk, or InvalidBuffer. The caller is responsible for
- * releasing *buf after it's done testing and setting bits, and must pass flags
- * for which it needs to check the value in visibility map.
+ * releasing *buf after it's done testing and setting bits.
*
* NOTE: This function is typically called without a lock on the heap page,
* so somebody else could change the bit just after we look at it. In fact,
{
BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
uint32 mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
- uint8 mapBit = HEAPBLK_TO_MAPBIT(heapBlk);
+ uint8 mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
char *map;
+ uint8 result;
#ifdef TRACE_VISIBILITYMAP
elog(DEBUG1, "vm_get_status %s %d", RelationGetRelationName(rel), heapBlk);
* here, but for performance reasons we make it the caller's job to worry
* about that.
*/
- return ((map[mapByte] >> mapBit) & VISIBILITYMAP_VALID_BITS);
+ result = ((map[mapByte] >> mapOffset) & VISIBILITYMAP_VALID_BITS);
+ return result;
}
/*
/* last remaining block, byte, and bit */
BlockNumber truncBlock = HEAPBLK_TO_MAPBLOCK(nheapblocks);
uint32 truncByte = HEAPBLK_TO_MAPBYTE(nheapblocks);
- uint8 truncBit = HEAPBLK_TO_MAPBIT(nheapblocks);
+ uint8 truncOffset = HEAPBLK_TO_OFFSET(nheapblocks);
#ifdef TRACE_VISIBILITYMAP
elog(DEBUG1, "vm_truncate %s %d", RelationGetRelationName(rel), nheapblocks);
* because we don't get a chance to clear the bits if the heap is extended
* again.
*/
- if (truncByte != 0 || truncBit != 0)
+ if (truncByte != 0 || truncOffset != 0)
{
Buffer mapBuffer;
Page page;
* ((1 << 7) - 1) = 01111111
*----
*/
- map[truncByte] &= (1 << truncBit) - 1;
+ map[truncByte] &= (1 << truncOffset) - 1;
MarkBufferDirty(mapBuffer);
UnlockReleaseBuffer(mapBuffer);
}
/*
- * If the page is marked as all-visible but not all-frozen, we should
- * so mark it. Note that all_frozen is only valid if all_visible is
- * true, so we must check both.
+ * If the all-visible page is turned out to be all-frozen but not marked,
+ * we should so mark it. Note that all_frozen is only valid if all_visible
+ * is true, so we must check both.
*/
else if (all_visible_according_to_vm && all_visible && all_frozen &&
!VM_ALL_FROZEN(onerel, blkno, &vmbuffer))
if (ItemIdIsDead(itemid))
{
all_visible = false;
+ *all_frozen = false;
break;
}
if (!HeapTupleHeaderXminCommitted(tuple.t_data))
{
all_visible = false;
+ *all_frozen = false;
break;
}
if (!TransactionIdPrecedes(xmin, OldestXmin))
{
all_visible = false;
+ *all_frozen = false;
break;
}
case HEAPTUPLE_RECENTLY_DEAD:
case HEAPTUPLE_INSERT_IN_PROGRESS:
case HEAPTUPLE_DELETE_IN_PROGRESS:
- all_visible = false;
- break;
-
+ {
+ all_visible = false;
+ *all_frozen = false;
+ break;
+ }
default:
elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
break;
}
} /* scan along page */
- /*
- * We don't bother clearing *all_frozen when the page is discovered not to
- * be all-visible, so do that now if necessary. The page might fail to be
- * all-frozen for other reasons anyway, but if it's not all-visible, then
- * it definitely isn't all-frozen.
- */
- if (!all_visible)
- *all_frozen = false;
-
return all_visible;
}
projects / postgresql / commitdiff