* visibilitymap_pin - pin a map page for setting a bit
* visibilitymap_pin_ok - check whether correct map page is already pinned
* visibilitymap_set - set a bit in a previously pinned page
- * visibilitymap_test - test if a bit is set
+ * visibilitymap_get_status - get status of bits
* visibilitymap_count - count number of bits set in visibility map
* visibilitymap_truncate - truncate the visibility map
*
* NOTES
*
- * The visibility map is a bitmap with one bit per heap page. A set bit means
- * that all tuples on the page are known visible to all transactions, and
- * therefore the page doesn't need to be vacuumed. The map is conservative in
- * the sense that we make sure that whenever a bit is set, we know the
- * condition is true, but if a bit is not set, it might or might not be true.
+ * The visibility map is a bitmap with two bits (all-visible and all-frozen)
+ * per heap page. A set all-visible bit means that all tuples on the page are
+ * known visible to all transactions, and therefore the page doesn't need to
+ * be vacuumed. A set all-frozen bit means that all tuples on the page are
+ * completely frozen, and therefore the page doesn't need to be vacuumed even
+ * if whole table scanning vacuum is required (e.g. anti-wraparound vacuum).
+ * The all-frozen bit must be set only when the page is already all-visible.
*
- * Clearing a visibility map bit is not separately WAL-logged. The callers
+ * The map is conservative in the sense that we make sure that whenever a bit
+ * 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
* must make sure that whenever a bit is cleared, the bit is cleared on WAL
* replay of the updating operation as well.
*
* When we *set* a visibility map during VACUUM, we must write WAL. This may
* seem counterintuitive, since the bit is basically a hint: if it is clear,
- * it may still be the case that every tuple on the page is visible to all
- * transactions; we just don't know that for certain. The difficulty is that
- * there are two bits which are typically set together: the PD_ALL_VISIBLE bit
- * on the page itself, and the visibility map bit. If a crash occurs after the
- * visibility map page makes it to disk and before the updated heap page makes
- * it to disk, redo must set the bit on the heap page. Otherwise, the next
- * insert, update, or delete on the heap page will fail to realize that the
- * visibility map bit must be cleared, possibly causing index-only scans to
- * return wrong answers.
+ * it may still be the case that every tuple on the page is all-visible or
+ * all-frozen we just don't know that for certain. The difficulty is that
+ * there are two bits which are typically set together: the PD_ALL_VISIBLE
+ * or PD_ALL_FROZEN bit on the page itself, and the corresponding visibility
+ * map bit. If a crash occurs after the visibility map page makes it to disk
+ * and before the updated heap page makes it to disk, redo must set the bit on
+ * the heap page. Otherwise, the next insert, update, or delete on the heap
+ * page will fail to realize that the visibility map bit must be cleared,
+ * possibly causing index-only scans to return wrong answers.
*
* VACUUM will normally skip pages for which the visibility map bit is set;
* such pages can't contain any dead tuples and therefore don't need vacuuming.
- * The visibility map is not used for anti-wraparound vacuums, because
- * an anti-wraparound vacuum needs to freeze tuples and observe the latest xid
- * present in the table, even on pages that don't have any dead tuples.
*
* LOCKING
*
*/
#define MAPSIZE (BLCKSZ - MAXALIGN(SizeOfPageHeaderData))
-/* Number of bits allocated for each heap block. */
-#define BITS_PER_HEAPBLOCK 1
-
-/* Number of heap blocks we can represent in one byte. */
-#define HEAPBLOCKS_PER_BYTE 8
-
/* 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)
-
-/* table for fast counting of set bits */
-static const uint8 number_of_ones[256] = {
- 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
- 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
- 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
- 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
- 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
- 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
- 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
- 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
+#define HEAPBLK_TO_MAPBIT(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] = {
+ 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2,
+ 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
+ 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2,
+ 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
+ 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
+ 2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4,
+ 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
+ 2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4,
+ 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2,
+ 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
+ 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2,
+ 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
+ 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
+ 2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4,
+ 1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
+ 2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4
+};
+static const uint8 number_of_ones_for_frozen[256] = {
+ 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2,
+ 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2,
+ 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
+ 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
+ 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2,
+ 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2,
+ 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
+ 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
+ 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
+ 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
+ 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4,
+ 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4,
+ 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
+ 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
+ 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4,
+ 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4
};
/* prototypes for internal routines */
/*
- * visibilitymap_clear - clear a bit in visibility map
+ * visibilitymap_clear - clear all bits 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 = 1 << mapBit;
+ uint8 mask = VISIBILITYMAP_VALID_BITS << mapBit;
char *map;
#ifdef TRACE_VISIBILITYMAP
* visibilitymap_set to actually set the bit.
*
* On entry, *buf should be InvalidBuffer or a valid buffer returned by
- * an earlier call to visibilitymap_pin or visibilitymap_test on the same
+ * an 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.
*
* visibilitymap_pin_ok - do we already have the correct page pinned?
*
* On entry, buf should be InvalidBuffer or a valid buffer returned by
- * an earlier call to visibilitymap_pin or visibilitymap_test on the same
+ * an earlier call to visibilitymap_pin or visibilitymap_get_status on the same
* relation. The return value indicates whether the buffer covers the
* given heapBlk.
*/
}
/*
- * visibilitymap_set - set a bit on a previously pinned page
+ * visibilitymap_set - set bit(s) on a previously pinned page
*
* recptr is the LSN of the XLOG record we're replaying, if we're in recovery,
* or InvalidXLogRecPtr in normal running. The page LSN is advanced to the
* one provided; in normal running, we generate a new XLOG record and set the
* page LSN to that value. cutoff_xid is the largest xmin on the page being
* marked all-visible; it is needed for Hot Standby, and can be
- * InvalidTransactionId if the page contains no tuples.
+ * InvalidTransactionId if the page contains no tuples. It can also be set
+ * to InvalidTransactionId when a page that is already all-visible is being
+ * marked all-frozen.
*
- * Caller is expected to set the heap page's PD_ALL_VISIBLE bit before calling
- * this function. Except in recovery, caller should also pass the heap
- * buffer. When checksums are enabled and we're not in recovery, we must add
- * the heap buffer to the WAL chain to protect it from being torn.
+ * Caller is expected to set the heap page's PD_ALL_VISIBLE or PD_ALL_FROZEN
+ * bit before calling this function. Except in recovery, caller should also
+ * pass the heap buffer and flags which indicates what flag we want to set.
+ * When checksums are enabled and we're not in recovery, we must add the heap
+ * buffer to the WAL chain to protect it from being torn.
*
* 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
*/
void
visibilitymap_set(Relation rel, BlockNumber heapBlk, Buffer heapBuf,
- XLogRecPtr recptr, Buffer vmBuf, TransactionId cutoff_xid)
+ XLogRecPtr recptr, Buffer vmBuf, TransactionId cutoff_xid,
+ uint8 flags)
{
BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
uint32 mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
uint8 mapBit = HEAPBLK_TO_MAPBIT(heapBlk);
Page page;
- char *map;
+ uint8 *map;
#ifdef TRACE_VISIBILITYMAP
elog(DEBUG1, "vm_set %s %d", RelationGetRelationName(rel), heapBlk);
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 VM buffer passed to visibilitymap_set");
page = BufferGetPage(vmBuf);
- map = PageGetContents(page);
+ map = (uint8 *)PageGetContents(page);
LockBuffer(vmBuf, BUFFER_LOCK_EXCLUSIVE);
- if (!(map[mapByte] & (1 << mapBit)))
+ if (flags != (map[mapByte] >> mapBit & VISIBILITYMAP_VALID_BITS))
{
START_CRIT_SECTION();
- map[mapByte] |= (1 << mapBit);
+ map[mapByte] |= (flags << mapBit);
MarkBufferDirty(vmBuf);
if (RelationNeedsWAL(rel))
{
Assert(!InRecovery);
recptr = log_heap_visible(rel->rd_node, heapBuf, vmBuf,
- cutoff_xid);
+ cutoff_xid, flags);
/*
* If data checksums are enabled (or wal_log_hints=on), we
{
Page heapPage = BufferGetPage(heapBuf);
- /* caller is expected to set PD_ALL_VISIBLE first */
- Assert(PageIsAllVisible(heapPage));
+ /* Caller is expected to set page-level bits first. */
+ Assert((flags & VISIBILITYMAP_ALL_VISIBLE) == 0 || PageIsAllVisible(heapPage));
+ Assert((flags & VISIBILITYMAP_ALL_FROZEN) == 0 || PageIsAllFrozen(heapPage));
+
PageSetLSN(heapPage, recptr);
}
}
}
/*
- * visibilitymap_test - test if a bit is set
+ * visibilitymap_get_status - get status of bits
*
- * Are all tuples on heapBlk visible to all, according to the visibility map?
+ * Are all tuples on heapBlk visible to all or are marked frozen, according
+ * to the visibility map?
*
* On entry, *buf should be InvalidBuffer or a valid buffer returned by an
- * earlier call to visibilitymap_pin or visibilitymap_test on the same
+ * 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.
+ * 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.
*
* 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,
* we might see the old value. It is the caller's responsibility to deal with
* all concurrency issues!
*/
-bool
-visibilitymap_test(Relation rel, BlockNumber heapBlk, Buffer *buf)
+uint8
+visibilitymap_get_status(Relation rel, BlockNumber heapBlk, Buffer *buf)
{
BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
uint32 mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
uint8 mapBit = HEAPBLK_TO_MAPBIT(heapBlk);
- bool result;
char *map;
#ifdef TRACE_VISIBILITYMAP
- elog(DEBUG1, "vm_test %s %d", RelationGetRelationName(rel), heapBlk);
+ elog(DEBUG1, "vm_get_status %s %d", RelationGetRelationName(rel), heapBlk);
#endif
/* Reuse the old pinned buffer if possible */
map = PageGetContents(BufferGetPage(*buf));
/*
- * A single-bit read is atomic. There could be memory-ordering effects
+ * 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] & (1 << mapBit)) ? true : false;
-
- return result;
+ return ((map[mapByte] >> mapBit) & VISIBILITYMAP_VALID_BITS);
}
/*
*
* Note: we ignore the possibility of race conditions when the table is being
* extended concurrently with the call. New pages added to the table aren't
- * going to be marked all-visible, so they won't affect the result.
+ * going to be marked all-visible or all-frozen, so they won't affect the result.
*/
-BlockNumber
-visibilitymap_count(Relation rel)
+void
+visibilitymap_count(Relation rel, BlockNumber *all_visible, BlockNumber *all_frozen)
{
- BlockNumber result = 0;
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;
for (i = 0; i < MAPSIZE; i++)
{
- result += number_of_ones[map[i]];
+ *all_visible += number_of_ones_for_visible[map[i]];
+ if (all_frozen)
+ *all_frozen += number_of_ones_for_frozen[map[i]];
}
ReleaseBuffer(mapBuffer);
}
-
- return result;
}
/*
static bool lazy_tid_reaped(ItemPointer itemptr, void *state);
static int vac_cmp_itemptr(const void *left, const void *right);
static bool heap_page_is_all_visible(Relation rel, Buffer buf,
- TransactionId *visibility_cutoff_xid);
+ TransactionId *visibility_cutoff_xid, bool *all_frozen);
/*
new_rel_tuples = vacrelstats->old_rel_tuples;
}
- new_rel_allvisible = visibilitymap_count(onerel);
+ visibilitymap_count(onerel, &new_rel_allvisible, NULL);
if (new_rel_allvisible > new_rel_pages)
new_rel_allvisible = new_rel_pages;
* maintain next_not_all_visible_block anyway, so as to set up the
* all_visible_according_to_vm flag correctly for each page.
*
- * Note: The value returned by visibilitymap_test could be slightly
+ * Note: The value returned by visibilitymap_get_status could be slightly
* out-of-date, since we make this test before reading the corresponding
* heap page or locking the buffer. This is OK. If we mistakenly think
* that the page is all-visible when in fact the flag's just been cleared,
next_not_all_visible_block < nblocks;
next_not_all_visible_block++)
{
- if (!visibilitymap_test(onerel, next_not_all_visible_block, &vmbuffer))
+ if (!VM_ALL_VISIBLE(onerel, next_not_all_visible_block, &vmbuffer))
break;
vacuum_delay_point();
}
Size freespace;
bool all_visible_according_to_vm;
bool all_visible;
+ bool all_frozen = true; /* provided all_visible is also true */
bool has_dead_tuples;
TransactionId visibility_cutoff_xid = InvalidTransactionId;
next_not_all_visible_block < nblocks;
next_not_all_visible_block++)
{
- if (!visibilitymap_test(onerel, next_not_all_visible_block,
- &vmbuffer))
+ if (!VM_ALL_VISIBLE(onerel, next_not_all_visible_block, &vmbuffer))
break;
vacuum_delay_point();
}
empty_pages++;
freespace = PageGetHeapFreeSpace(page);
- /* empty pages are always all-visible */
+ /* empty pages are always all-visible and all-frozen */
if (!PageIsAllVisible(page))
{
START_CRIT_SECTION();
log_newpage_buffer(buf, true);
PageSetAllVisible(page);
+ PageSetAllFrozen(page);
visibilitymap_set(onerel, blkno, buf, InvalidXLogRecPtr,
- vmbuffer, InvalidTransactionId);
+ vmbuffer, InvalidTransactionId,
+ VISIBILITYMAP_ALL_VISIBLE | VISIBILITYMAP_ALL_FROZEN);
END_CRIT_SECTION();
}
if (heap_prepare_freeze_tuple(tuple.t_data, FreezeLimit,
MultiXactCutoff, &frozen[nfrozen]))
frozen[nfrozen++].offset = offnum;
+ else if (heap_tuple_needs_eventual_freeze(tuple.t_data))
+ all_frozen = false;
}
} /* scan along page */
/* mark page all-visible, if appropriate */
if (all_visible && !all_visible_according_to_vm)
{
+ uint8 flags = VISIBILITYMAP_ALL_VISIBLE;
+
/*
* It should never be the case that the visibility map page is set
* while the page-level bit is clear, but the reverse is allowed
* rare cases after a crash, it is not worth optimizing.
*/
PageSetAllVisible(page);
+ if (all_frozen)
+ {
+ PageSetAllFrozen(page);
+ flags |= VISIBILITYMAP_ALL_FROZEN;
+ }
MarkBufferDirty(buf);
visibilitymap_set(onerel, blkno, buf, InvalidXLogRecPtr,
- vmbuffer, visibility_cutoff_xid);
+ vmbuffer, visibility_cutoff_xid, flags);
}
/*
* that something bad has happened.
*/
else if (all_visible_according_to_vm && !PageIsAllVisible(page)
- && visibilitymap_test(onerel, blkno, &vmbuffer))
+ && VM_ALL_VISIBLE(onerel, blkno, &vmbuffer))
{
elog(WARNING, "page is not marked all-visible but visibility map bit is set in relation \"%s\" page %u",
relname, blkno);
visibilitymap_clear(onerel, blkno, vmbuffer);
}
+ /*
+ * 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.
+ */
+ else if (all_visible_according_to_vm && all_visible && all_frozen &&
+ !VM_ALL_FROZEN(onerel, blkno, &vmbuffer))
+ {
+ /* Page is marked all-visible but should be all-frozen */
+ PageSetAllFrozen(page);
+ MarkBufferDirty(buf);
+
+ /*
+ * We can pass InvalidTransactionId as the cutoff XID here,
+ * because setting the all-frozen bit doesn't cause recovery
+ * conflicts.
+ */
+ visibilitymap_set(onerel, blkno, buf, InvalidXLogRecPtr,
+ vmbuffer, InvalidTransactionId,
+ VISIBILITYMAP_ALL_FROZEN);
+ }
+
UnlockReleaseBuffer(buf);
/* Remember the location of the last page with nonremovable tuples */
OffsetNumber unused[MaxOffsetNumber];
int uncnt = 0;
TransactionId visibility_cutoff_xid;
+ bool all_frozen;
START_CRIT_SECTION();
* dirty, exclusively locked, and, if needed, a full page image has been
* emitted in the log_heap_clean() above.
*/
- if (heap_page_is_all_visible(onerel, buffer, &visibility_cutoff_xid))
+ if (heap_page_is_all_visible(onerel, buffer, &visibility_cutoff_xid,
+ &all_frozen))
+ {
PageSetAllVisible(page);
+ if (all_frozen)
+ PageSetAllFrozen(page);
+ }
/*
* All the changes to the heap page have been done. If the all-visible
- * flag is now set, also set the VM bit.
+ * flag is now set, also set the VM all-visible bit (and, if possible,
+ * the all-frozen bit) unless this has already been done previously.
*/
- if (PageIsAllVisible(page) &&
- !visibilitymap_test(onerel, blkno, vmbuffer))
+ if (PageIsAllVisible(page))
{
+ uint8 vm_status = visibilitymap_get_status(onerel, blkno, vmbuffer);
+ uint8 flags = 0;
+
+ /* Set the VM all-frozen bit to flag, if needed */
+ if ((vm_status & VISIBILITYMAP_ALL_VISIBLE) == 0)
+ flags |= VISIBILITYMAP_ALL_VISIBLE;
+ if ((vm_status & VISIBILITYMAP_ALL_FROZEN) == 0 && all_frozen)
+ flags |= VISIBILITYMAP_ALL_FROZEN;
+
Assert(BufferIsValid(*vmbuffer));
- visibilitymap_set(onerel, blkno, buffer, InvalidXLogRecPtr, *vmbuffer,
- visibility_cutoff_xid);
+ if (flags != 0)
+ visibilitymap_set(onerel, blkno, buffer, InvalidXLogRecPtr,
+ *vmbuffer, visibility_cutoff_xid, flags);
}
return tupindex;
/*
* Check if every tuple in the given page is visible to all current and future
* transactions. Also return the visibility_cutoff_xid which is the highest
- * xmin amongst the visible tuples.
+ * xmin amongst the visible tuples. Set *all_frozen to true if every tuple
+ * on this page is frozen.
*/
static bool
-heap_page_is_all_visible(Relation rel, Buffer buf, TransactionId *visibility_cutoff_xid)
+heap_page_is_all_visible(Relation rel, Buffer buf,
+ TransactionId *visibility_cutoff_xid,
+ bool *all_frozen)
{
Page page = BufferGetPage(buf);
BlockNumber blockno = BufferGetBlockNumber(buf);
bool all_visible = true;
*visibility_cutoff_xid = InvalidTransactionId;
+ *all_frozen = true;
/*
* This is a stripped down version of the line pointer scan in
/* Track newest xmin on page. */
if (TransactionIdFollows(xmin, *visibility_cutoff_xid))
*visibility_cutoff_xid = xmin;
+
+ /* Check whether this tuple is already frozen or not */
+ if (all_visible && *all_frozen &&
+ heap_tuple_needs_eventual_freeze(tuple.t_data))
+ *all_frozen = false;
}
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