/*
* Bulk deletion of all index entries pointing to a set of heap tuples and
* check invalid tuples after crash recovery.
* The set of target tuples is specified via a callback routine that tells
* whether any given heap tuple (identified by ItemPointer) is being deleted.
*
* Result: a palloc'd struct containing statistical info for VACUUM displays.
*/
Datum
gistbulkdelete(PG_FUNCTION_ARGS)
{
IndexVacuumInfo *info = (IndexVacuumInfo *) PG_GETARG_POINTER(0);
GistBulkDeleteResult *stats = (GistBulkDeleteResult *) PG_GETARG_POINTER(1);
IndexBulkDeleteCallback callback = (IndexBulkDeleteCallback) PG_GETARG_POINTER(2);
void *callback_state = (void *) PG_GETARG_POINTER(3);
Relation rel = info->index;
GistBDItem *stack,
*ptr;
/* first time through? */
if (stats == NULL)
stats = (GistBulkDeleteResult *) palloc0(sizeof(GistBulkDeleteResult));
/* we'll re-count the tuples each time */
stats->std.estimated_count = false;
stats->std.num_index_tuples = 0;
stack = (GistBDItem *) palloc0(sizeof(GistBDItem));
stack->blkno = GIST_ROOT_BLKNO;
while (stack)
{
Buffer buffer;
Page page;
OffsetNumber i,
maxoff;
IndexTuple idxtuple;
ItemId iid;
buffer = ReadBufferExtended(rel, MAIN_FORKNUM, stack->blkno,
RBM_NORMAL, info->strategy);
LockBuffer(buffer, GIST_SHARE);
gistcheckpage(rel, buffer);
page = (Page) BufferGetPage(buffer);
if (GistPageIsLeaf(page))
{
OffsetNumber todelete[MaxOffsetNumber];
int ntodelete = 0;
LockBuffer(buffer, GIST_UNLOCK);
LockBuffer(buffer, GIST_EXCLUSIVE);
page = (Page) BufferGetPage(buffer);
if (stack->blkno == GIST_ROOT_BLKNO && !GistPageIsLeaf(page))
{
/* only the root can become non-leaf during relock */
UnlockReleaseBuffer(buffer);
/* one more check */
continue;
}
/*
* check for split proceeded after look at parent, we should check
* it after relock
*/
pushStackIfSplited(page, stack);
/*
* Remove deletable tuples from page
*/
maxoff = PageGetMaxOffsetNumber(page);
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
iid = PageGetItemId(page, i);
idxtuple = (IndexTuple) PageGetItem(page, iid);
if (callback(&(idxtuple->t_tid), callback_state))
{
todelete[ntodelete] = i - ntodelete;
ntodelete++;
stats->std.tuples_removed += 1;
}
else
stats->std.num_index_tuples += 1;
}
if (ntodelete)
{
START_CRIT_SECTION();
MarkBufferDirty(buffer);
for (i = 0; i < ntodelete; i++)
PageIndexTupleDelete(page, todelete[i]);
GistMarkTuplesDeleted(page);
if (!rel->rd_istemp)
{
XLogRecData *rdata;
XLogRecPtr recptr;
gistxlogPageUpdate *xlinfo;
rdata = formUpdateRdata(rel->rd_node, buffer,
todelete, ntodelete,
NULL, 0,
NULL);
xlinfo = (gistxlogPageUpdate *) rdata->next->data;
recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_PAGE_UPDATE, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
pfree(xlinfo);
pfree(rdata);
}
else
PageSetLSN(page, GetXLogRecPtrForTemp());
END_CRIT_SECTION();
}
}
else
{
/* check for split proceeded after look at parent */
pushStackIfSplited(page, stack);
maxoff = PageGetMaxOffsetNumber(page);
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
iid = PageGetItemId(page, i);
idxtuple = (IndexTuple) PageGetItem(page, iid);
ptr = (GistBDItem *) palloc(sizeof(GistBDItem));
ptr->blkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
ptr->parentlsn = PageGetLSN(page);
ptr->next = stack->next;
stack->next = ptr;
if (GistTupleIsInvalid(idxtuple))
stats->needReindex = true;
}
}
UnlockReleaseBuffer(buffer);
ptr = stack->next;
pfree(stack);
stack = ptr;
vacuum_delay_point();
}
PG_RETURN_POINTER(stats);
}
/*
* Scan through posting tree, delete empty tuples from leaf pages.
* Also, this function collects empty subtrees (with all empty leafs).
* For parents of these subtrees CleanUp lock is taken, then we call
* ScanToDelete. This is done for every inner page, which points to
* empty subtree.
*/
static bool
ginVacuumPostingTreeLeaves(GinVacuumState *gvs, BlockNumber blkno, bool isRoot)
{
Buffer buffer;
Page page;
bool hasVoidPage = FALSE;
MemoryContext oldCxt;
buffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, blkno,
RBM_NORMAL, gvs->strategy);
page = BufferGetPage(buffer);
ginTraverseLock(buffer, false);
Assert(GinPageIsData(page));
if (GinPageIsLeaf(page))
{
oldCxt = MemoryContextSwitchTo(gvs->tmpCxt);
ginVacuumPostingTreeLeaf(gvs->index, buffer, gvs);
MemoryContextSwitchTo(oldCxt);
MemoryContextReset(gvs->tmpCxt);
/* if root is a leaf page, we don't desire further processing */
if (GinDataLeafPageIsEmpty(page))
hasVoidPage = TRUE;
UnlockReleaseBuffer(buffer);
return hasVoidPage;
}
else
{
OffsetNumber i;
bool hasEmptyChild = FALSE;
bool hasNonEmptyChild = FALSE;
OffsetNumber maxoff = GinPageGetOpaque(page)->maxoff;
BlockNumber *children = palloc(sizeof(BlockNumber) * (maxoff + 1));
/*
* Read all children BlockNumbers. Not sure it is safe if there are
* many concurrent vacuums.
*/
for (i = FirstOffsetNumber; i <= maxoff; i++)
{
PostingItem *pitem = GinDataPageGetPostingItem(page, i);
children[i] = PostingItemGetBlockNumber(pitem);
}
UnlockReleaseBuffer(buffer);
for (i = FirstOffsetNumber; i <= maxoff; i++)
{
if (ginVacuumPostingTreeLeaves(gvs, children[i], FALSE))
hasEmptyChild = TRUE;
else
hasNonEmptyChild = TRUE;
}
pfree(children);
vacuum_delay_point();
/*
* All subtree is empty - just return TRUE to indicate that parent
* must do a cleanup. Unless we are ROOT an there is way to go upper.
*/
if (hasEmptyChild && !hasNonEmptyChild && !isRoot)
return TRUE;
if (hasEmptyChild)
{
DataPageDeleteStack root,
*ptr,
*tmp;
buffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, blkno,
RBM_NORMAL, gvs->strategy);
LockBufferForCleanup(buffer);
memset(&root, 0, sizeof(DataPageDeleteStack));
root.leftBlkno = InvalidBlockNumber;
root.isRoot = TRUE;
ginScanToDelete(gvs, blkno, TRUE, &root, InvalidOffsetNumber);
ptr = root.child;
while (ptr)
{
tmp = ptr->child;
pfree(ptr);
ptr = tmp;
}
UnlockReleaseBuffer(buffer);
}
/* Here we have deleted all empty subtrees */
return FALSE;
}
}
IndexBulkDeleteResult *
ginvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
{
Relation index = info->index;
bool needLock;
BlockNumber npages,
blkno;
BlockNumber totFreePages;
GinState ginstate;
GinStatsData idxStat;
/*
* In an autovacuum analyze, we want to clean up pending insertions.
* Otherwise, an ANALYZE-only call is a no-op.
*/
if (info->analyze_only)
{
if (IsAutoVacuumWorkerProcess())
{
initGinState(&ginstate, index);
ginInsertCleanup(&ginstate, false, true, stats);
}
return stats;
}
/*
* Set up all-zero stats and cleanup pending inserts if ginbulkdelete
* wasn't called
*/
if (stats == NULL)
{
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
initGinState(&ginstate, index);
ginInsertCleanup(&ginstate, !IsAutoVacuumWorkerProcess(),
false, stats);
}
memset(&idxStat, 0, sizeof(idxStat));
/*
* XXX we always report the heap tuple count as the number of index
* entries. This is bogus if the index is partial, but it's real hard to
* tell how many distinct heap entries are referenced by a GIN index.
*/
stats->num_index_tuples = info->num_heap_tuples;
stats->estimated_count = info->estimated_count;
/*
* Need lock unless it's local to this backend.
*/
needLock = !RELATION_IS_LOCAL(index);
if (needLock)
LockRelationForExtension(index, ExclusiveLock);
npages = RelationGetNumberOfBlocks(index);
if (needLock)
UnlockRelationForExtension(index, ExclusiveLock);
totFreePages = 0;
for (blkno = GIN_ROOT_BLKNO; blkno < npages; blkno++)
{
Buffer buffer;
Page page;
vacuum_delay_point();
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
LockBuffer(buffer, GIN_SHARE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew(page) || GinPageIsDeleted(page))
{
Assert(blkno != GIN_ROOT_BLKNO);
RecordFreeIndexPage(index, blkno);
totFreePages++;
}
else if (GinPageIsData(page))
{
idxStat.nDataPages++;
}
else if (!GinPageIsList(page))
{
idxStat.nEntryPages++;
if (GinPageIsLeaf(page))
idxStat.nEntries += PageGetMaxOffsetNumber(page);
}
UnlockReleaseBuffer(buffer);
}
/* Update the metapage with accurate page and entry counts */
idxStat.nTotalPages = npages;
ginUpdateStats(info->index, &idxStat);
/* Finally, vacuum the FSM */
IndexFreeSpaceMapVacuum(info->index);
stats->pages_free = totFreePages;
if (needLock)
LockRelationForExtension(index, ExclusiveLock);
stats->num_pages = RelationGetNumberOfBlocks(index);
if (needLock)
UnlockRelationForExtension(index, ExclusiveLock);
return stats;
}
/*
* btvacuumpage --- VACUUM one page
*
* This processes a single page for btvacuumscan(). In some cases we
* must go back and re-examine previously-scanned pages; this routine
* recurses when necessary to handle that case.
*
* blkno is the page to process. orig_blkno is the highest block number
* reached by the outer btvacuumscan loop (the same as blkno, unless we
* are recursing to re-examine a previous page).
*/
static void
btvacuumpage(BTVacState *vstate, BlockNumber blkno, BlockNumber orig_blkno)
{
IndexVacuumInfo *info = vstate->info;
IndexBulkDeleteResult *stats = vstate->stats;
IndexBulkDeleteCallback callback = vstate->callback;
void *callback_state = vstate->callback_state;
Relation rel = info->index;
bool delete_now;
BlockNumber recurse_to;
Buffer buf;
Page page;
BTPageOpaque opaque;
restart:
delete_now = false;
recurse_to = P_NONE;
/* call vacuum_delay_point while not holding any buffer lock */
vacuum_delay_point();
/*
* We can't use _bt_getbuf() here because it always applies
* _bt_checkpage(), which will barf on an all-zero page. We want to
* recycle all-zero pages, not fail. Also, we want to use a nondefault
* buffer access strategy.
*/
buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL,
info->strategy);
LockBuffer(buf, BT_READ);
page = BufferGetPage(buf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
if (!PageIsNew(page))
_bt_checkpage(rel, buf);
/*
* If we are recursing, the only case we want to do anything with is a
* live leaf page having the current vacuum cycle ID. Any other state
* implies we already saw the page (eg, deleted it as being empty).
*/
if (blkno != orig_blkno)
{
if (_bt_page_recyclable(page) ||
P_IGNORE(opaque) ||
!P_ISLEAF(opaque) ||
opaque->btpo_cycleid != vstate->cycleid)
{
_bt_relbuf(rel, buf);
return;
}
}
/* Page is valid, see what to do with it */
if (_bt_page_recyclable(page))
{
/* Okay to recycle this page */
RecordFreeIndexPage(rel, blkno);
vstate->totFreePages++;
stats->pages_deleted++;
}
else if (P_ISDELETED(opaque))
{
/* Already deleted, but can't recycle yet */
stats->pages_deleted++;
}
else if (P_ISHALFDEAD(opaque))
{
/* Half-dead, try to delete */
delete_now = true;
}
else if (P_ISLEAF(opaque))
{
OffsetNumber deletable[MaxOffsetNumber];
int ndeletable;
OffsetNumber offnum,
minoff,
maxoff;
/*
* Trade in the initial read lock for a super-exclusive write lock on
* this page. We must get such a lock on every leaf page over the
* course of the vacuum scan, whether or not it actually contains any
* deletable tuples --- see nbtree/README.
*/
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
LockBufferForCleanup(buf);
/*
* Remember highest leaf page number we've taken cleanup lock on; see
* notes in btvacuumscan
*/
if (blkno > vstate->lastBlockLocked)
vstate->lastBlockLocked = blkno;
/*
* Check whether we need to recurse back to earlier pages. What we
* are concerned about is a page split that happened since we started
* the vacuum scan. If the split moved some tuples to a lower page
* then we might have missed 'em. If so, set up for tail recursion.
* (Must do this before possibly clearing btpo_cycleid below!)
*/
if (vstate->cycleid != 0 &&
opaque->btpo_cycleid == vstate->cycleid &&
!(opaque->btpo_flags & BTP_SPLIT_END) &&
!P_RIGHTMOST(opaque) &&
opaque->btpo_next < orig_blkno)
recurse_to = opaque->btpo_next;
/*
* Scan over all items to see which ones need deleted according to the
* callback function.
*/
ndeletable = 0;
minoff = P_FIRSTDATAKEY(opaque);
maxoff = PageGetMaxOffsetNumber(page);
if (callback)
{
for (offnum = minoff;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
IndexTuple itup;
ItemPointer htup;
itup = (IndexTuple) PageGetItem(page,
PageGetItemId(page, offnum));
htup = &(itup->t_tid);
/*
* During Hot Standby we currently assume that
* XLOG_BTREE_VACUUM records do not produce conflicts. That is
* only true as long as the callback function depends only
* upon whether the index tuple refers to heap tuples removed
* in the initial heap scan. When vacuum starts it derives a
* value of OldestXmin. Backends taking later snapshots could
* have a RecentGlobalXmin with a later xid than the vacuum's
* OldestXmin, so it is possible that row versions deleted
* after OldestXmin could be marked as killed by other
* backends. The callback function *could* look at the index
* tuple state in isolation and decide to delete the index
* tuple, though currently it does not. If it ever did, we
* would need to reconsider whether XLOG_BTREE_VACUUM records
* should cause conflicts. If they did cause conflicts they
* would be fairly harsh conflicts, since we haven't yet
* worked out a way to pass a useful value for
* latestRemovedXid on the XLOG_BTREE_VACUUM records. This
* applies to *any* type of index that marks index tuples as
* killed.
*/
if (callback(htup, callback_state))
deletable[ndeletable++] = offnum;
}
}
/*
* Apply any needed deletes. We issue just one _bt_delitems_vacuum()
* call per page, so as to minimize WAL traffic.
*/
if (ndeletable > 0)
{
/*
* Notice that the issued XLOG_BTREE_VACUUM WAL record includes an
* instruction to the replay code to get cleanup lock on all pages
* between the previous lastBlockVacuumed and this page. This
* ensures that WAL replay locks all leaf pages at some point.
*
* Since we can visit leaf pages out-of-order when recursing,
* replay might end up locking such pages an extra time, but it
* doesn't seem worth the amount of bookkeeping it'd take to avoid
* that.
*/
_bt_delitems_vacuum(rel, buf, deletable, ndeletable,
vstate->lastBlockVacuumed);
/*
* Remember highest leaf page number we've issued a
* XLOG_BTREE_VACUUM WAL record for.
*/
if (blkno > vstate->lastBlockVacuumed)
vstate->lastBlockVacuumed = blkno;
stats->tuples_removed += ndeletable;
/* must recompute maxoff */
maxoff = PageGetMaxOffsetNumber(page);
}
else
{
/*
* If the page has been split during this vacuum cycle, it seems
* worth expending a write to clear btpo_cycleid even if we don't
* have any deletions to do. (If we do, _bt_delitems_vacuum takes
* care of this.) This ensures we won't process the page again.
*
* We treat this like a hint-bit update because there's no need to
* WAL-log it.
*/
if (vstate->cycleid != 0 &&
opaque->btpo_cycleid == vstate->cycleid)
{
opaque->btpo_cycleid = 0;
MarkBufferDirtyHint(buf, true);
}
}
/*
* If it's now empty, try to delete; else count the live tuples. We
* don't delete when recursing, though, to avoid putting entries into
* freePages out-of-order (doesn't seem worth any extra code to handle
* the case).
*/
if (minoff > maxoff)
delete_now = (blkno == orig_blkno);
else
stats->num_index_tuples += maxoff - minoff + 1;
}
if (delete_now)
{
MemoryContext oldcontext;
int ndel;
/* Run pagedel in a temp context to avoid memory leakage */
MemoryContextReset(vstate->pagedelcontext);
oldcontext = MemoryContextSwitchTo(vstate->pagedelcontext);
ndel = _bt_pagedel(rel, buf, NULL);
/* count only this page, else may double-count parent */
if (ndel)
stats->pages_deleted++;
MemoryContextSwitchTo(oldcontext);
/* pagedel released buffer, so we shouldn't */
}
else
_bt_relbuf(rel, buf);
/*
* This is really tail recursion, but if the compiler is too stupid to
* optimize it as such, we'd eat an uncomfortably large amount of stack
* space per recursion level (due to the deletable[] array). A failure is
* improbable since the number of levels isn't likely to be large ... but
* just in case, let's hand-optimize into a loop.
*/
if (recurse_to != P_NONE)
{
blkno = recurse_to;
goto restart;
}
}
/*
* Delete a posting tree page.
*/
static void
ginDeletePage(GinVacuumState *gvs, BlockNumber deleteBlkno, BlockNumber leftBlkno,
BlockNumber parentBlkno, OffsetNumber myoff, bool isParentRoot)
{
Buffer dBuffer;
Buffer lBuffer;
Buffer pBuffer;
Page page,
parentPage;
BlockNumber rightlink;
/*
* This function MUST be called only if someone of parent pages hold
* exclusive cleanup lock. This guarantees that no insertions currently
* happen in this subtree. Caller also acquire Exclusive lock on deletable
* page and is acquiring and releasing exclusive lock on left page before.
* Left page was locked and released. Then parent and this page are
* locked. We acquire left page lock here only to mark page dirty after
* changing right pointer.
*/
lBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, leftBlkno,
RBM_NORMAL, gvs->strategy);
dBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, deleteBlkno,
RBM_NORMAL, gvs->strategy);
pBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, parentBlkno,
RBM_NORMAL, gvs->strategy);
LockBuffer(lBuffer, GIN_EXCLUSIVE);
START_CRIT_SECTION();
/* Unlink the page by changing left sibling's rightlink */
page = BufferGetPage(dBuffer);
rightlink = GinPageGetOpaque(page)->rightlink;
page = BufferGetPage(lBuffer);
GinPageGetOpaque(page)->rightlink = rightlink;
/* Delete downlink from parent */
parentPage = BufferGetPage(pBuffer);
#ifdef USE_ASSERT_CHECKING
do
{
PostingItem *tod = GinDataPageGetPostingItem(parentPage, myoff);
Assert(PostingItemGetBlockNumber(tod) == deleteBlkno);
} while (0);
#endif
GinPageDeletePostingItem(parentPage, myoff);
page = BufferGetPage(dBuffer);
/*
* we shouldn't change rightlink field to save workability of running
* search scan
*/
GinPageGetOpaque(page)->flags = GIN_DELETED;
MarkBufferDirty(pBuffer);
MarkBufferDirty(lBuffer);
MarkBufferDirty(dBuffer);
if (RelationNeedsWAL(gvs->index))
{
XLogRecPtr recptr;
ginxlogDeletePage data;
/*
* We can't pass REGBUF_STANDARD for the deleted page, because we
* didn't set pd_lower on pre-9.4 versions. The page might've been
* binary-upgraded from an older version, and hence not have pd_lower
* set correctly. Ditto for the left page, but removing the item from
* the parent updated its pd_lower, so we know that's OK at this
* point.
*/
XLogBeginInsert();
XLogRegisterBuffer(0, dBuffer, 0);
XLogRegisterBuffer(1, pBuffer, REGBUF_STANDARD);
XLogRegisterBuffer(2, lBuffer, 0);
data.parentOffset = myoff;
data.rightLink = GinPageGetOpaque(page)->rightlink;
XLogRegisterData((char *) &data, sizeof(ginxlogDeletePage));
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_DELETE_PAGE);
PageSetLSN(page, recptr);
PageSetLSN(parentPage, recptr);
PageSetLSN(BufferGetPage(lBuffer), recptr);
}
ReleaseBuffer(pBuffer);
UnlockReleaseBuffer(lBuffer);
ReleaseBuffer(dBuffer);
END_CRIT_SECTION();
gvs->result->pages_deleted++;
}
/*
* lazy_scan_heap() -- scan an open heap relation
*
* This routine prunes each page in the heap, which will among other
* things truncate dead tuples to dead line pointers, defragment the
* page, and set commit status bits (see heap_page_prune). It also builds
* lists of dead tuples and pages with free space, calculates statistics
* on the number of live tuples in the heap, and marks pages as
* all-visible if appropriate. When done, or when we run low on space for
* dead-tuple TIDs, invoke vacuuming of indexes and call lazy_vacuum_heap
* to reclaim dead line pointers.
*
* If there are no indexes then we can reclaim line pointers on the fly;
* dead line pointers need only be retained until all index pointers that
* reference them have been killed.
*/
static void
lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
Relation *Irel, int nindexes, bool scan_all)
{
BlockNumber nblocks,
blkno;
HeapTupleData tuple;
char *relname;
BlockNumber empty_pages,
vacuumed_pages;
double num_tuples,
tups_vacuumed,
nkeep,
nunused;
IndexBulkDeleteResult **indstats;
int i;
PGRUsage ru0;
Buffer vmbuffer = InvalidBuffer;
BlockNumber next_not_all_visible_block;
bool skipping_all_visible_blocks;
pg_rusage_init(&ru0);
relname = RelationGetRelationName(onerel);
ereport(elevel,
(errmsg("vacuuming \"%s.%s\"",
get_namespace_name(RelationGetNamespace(onerel)),
relname)));
empty_pages = vacuumed_pages = 0;
num_tuples = tups_vacuumed = nkeep = nunused = 0;
indstats = (IndexBulkDeleteResult **)
palloc0(nindexes * sizeof(IndexBulkDeleteResult *));
nblocks = RelationGetNumberOfBlocks(onerel);
vacrelstats->rel_pages = nblocks;
vacrelstats->scanned_pages = 0;
vacrelstats->nonempty_pages = 0;
vacrelstats->latestRemovedXid = InvalidTransactionId;
lazy_space_alloc(vacrelstats, nblocks);
/*
* We want to skip pages that don't require vacuuming according to the
* visibility map, but only when we can skip at least SKIP_PAGES_THRESHOLD
* consecutive pages. Since we're reading sequentially, the OS should be
* doing readahead for us, so there's no gain in skipping a page now and
* then; that's likely to disable readahead and so be counterproductive.
* Also, skipping even a single page means that we can't update
* relfrozenxid, so we only want to do it if we can skip a goodly number
* of pages.
*
* Before entering the main loop, establish the invariant that
* next_not_all_visible_block is the next block number >= blkno that's not
* all-visible according to the visibility map, or nblocks if there's no
* such block. Also, we set up the skipping_all_visible_blocks flag,
* which is needed because we need hysteresis in the decision: once we've
* started skipping blocks, we may as well skip everything up to the next
* not-all-visible block.
*
* Note: if scan_all is true, we won't actually skip any pages; but we
* 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
* 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,
* we might fail to vacuum the page. But it's OK to skip pages when
* scan_all is not set, so no great harm done; the next vacuum will find
* them. If we make the reverse mistake and vacuum a page unnecessarily,
* it'll just be a no-op.
*/
for (next_not_all_visible_block = 0;
next_not_all_visible_block < nblocks;
next_not_all_visible_block++)
{
if (!visibilitymap_test(onerel, next_not_all_visible_block, &vmbuffer))
break;
vacuum_delay_point();
}
if (next_not_all_visible_block >= SKIP_PAGES_THRESHOLD)
skipping_all_visible_blocks = true;
else
skipping_all_visible_blocks = false;
for (blkno = 0; blkno < nblocks; blkno++)
{
Buffer buf;
Page page;
OffsetNumber offnum,
maxoff;
bool tupgone,
hastup;
int prev_dead_count;
OffsetNumber frozen[MaxOffsetNumber];
int nfrozen;
Size freespace;
bool all_visible_according_to_vm;
bool all_visible;
bool has_dead_tuples;
TransactionId visibility_cutoff_xid = InvalidTransactionId;
if (blkno == next_not_all_visible_block)
{
/* Time to advance next_not_all_visible_block */
for (next_not_all_visible_block++;
next_not_all_visible_block < nblocks;
next_not_all_visible_block++)
{
if (!visibilitymap_test(onerel, next_not_all_visible_block,
&vmbuffer))
break;
vacuum_delay_point();
}
/*
* We know we can't skip the current block. But set up
* skipping_all_visible_blocks to do the right thing at the
* following blocks.
*/
if (next_not_all_visible_block - blkno > SKIP_PAGES_THRESHOLD)
skipping_all_visible_blocks = true;
else
skipping_all_visible_blocks = false;
all_visible_according_to_vm = false;
}
else
{
/* Current block is all-visible */
if (skipping_all_visible_blocks && !scan_all)
continue;
all_visible_according_to_vm = true;
}
vacuum_delay_point();
/*
* If we are close to overrunning the available space for dead-tuple
* TIDs, pause and do a cycle of vacuuming before we tackle this page.
*/
if ((vacrelstats->max_dead_tuples - vacrelstats->num_dead_tuples) < MaxHeapTuplesPerPage &&
vacrelstats->num_dead_tuples > 0)
{
/*
* Before beginning index vacuuming, we release any pin we may
* hold on the visibility map page. This isn't necessary for
* correctness, but we do it anyway to avoid holding the pin
* across a lengthy, unrelated operation.
*/
if (BufferIsValid(vmbuffer))
{
ReleaseBuffer(vmbuffer);
vmbuffer = InvalidBuffer;
}
/* Log cleanup info before we touch indexes */
vacuum_log_cleanup_info(onerel, vacrelstats);
/* Remove index entries */
for (i = 0; i < nindexes; i++)
lazy_vacuum_index(Irel[i],
&indstats[i],
vacrelstats);
/* Remove tuples from heap */
lazy_vacuum_heap(onerel, vacrelstats);
/*
* Forget the now-vacuumed tuples, and press on, but be careful
* not to reset latestRemovedXid since we want that value to be
* valid.
*/
vacrelstats->num_dead_tuples = 0;
vacrelstats->num_index_scans++;
}
/*
* Pin the visibility map page in case we need to mark the page
* all-visible. In most cases this will be very cheap, because we'll
* already have the correct page pinned anyway. However, it's
* possible that (a) next_not_all_visible_block is covered by a
* different VM page than the current block or (b) we released our pin
* and did a cycle of index vacuuming.
*/
visibilitymap_pin(onerel, blkno, &vmbuffer);
buf = ReadBufferExtended(onerel, MAIN_FORKNUM, blkno,
RBM_NORMAL, vac_strategy);
/* We need buffer cleanup lock so that we can prune HOT chains. */
if (!ConditionalLockBufferForCleanup(buf))
{
/*
* If we're not scanning the whole relation to guard against XID
* wraparound, it's OK to skip vacuuming a page. The next vacuum
* will clean it up.
*/
if (!scan_all)
{
ReleaseBuffer(buf);
continue;
}
/*
* If this is a wraparound checking vacuum, then we read the page
* with share lock to see if any xids need to be frozen. If the
* page doesn't need attention we just skip and continue. If it
* does, we wait for cleanup lock.
*
* We could defer the lock request further by remembering the page
* and coming back to it later, or we could even register
* ourselves for multiple buffers and then service whichever one
* is received first. For now, this seems good enough.
*/
LockBuffer(buf, BUFFER_LOCK_SHARE);
if (!lazy_check_needs_freeze(buf))
{
UnlockReleaseBuffer(buf);
continue;
}
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
LockBufferForCleanup(buf);
/* drop through to normal processing */
}
vacrelstats->scanned_pages++;
page = BufferGetPage(buf);
if (PageIsNew(page))
{
/*
* An all-zeroes page could be left over if a backend extends the
* relation but crashes before initializing the page. Reclaim such
* pages for use.
*
* We have to be careful here because we could be looking at a
* page that someone has just added to the relation and not yet
* been able to initialize (see RelationGetBufferForTuple). To
* protect against that, release the buffer lock, grab the
* relation extension lock momentarily, and re-lock the buffer. If
* the page is still uninitialized by then, it must be left over
* from a crashed backend, and we can initialize it.
*
* We don't really need the relation lock when this is a new or
* temp relation, but it's probably not worth the code space to
* check that, since this surely isn't a critical path.
*
* Note: the comparable code in vacuum.c need not worry because
* it's got exclusive lock on the whole relation.
*/
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
LockRelationForExtension(onerel, ExclusiveLock);
UnlockRelationForExtension(onerel, ExclusiveLock);
LockBufferForCleanup(buf);
if (PageIsNew(page))
{
ereport(WARNING,
(errmsg("relation \"%s\" page %u is uninitialized --- fixing",
relname, blkno)));
PageInit(page, BufferGetPageSize(buf), 0);
empty_pages++;
}
freespace = PageGetHeapFreeSpace(page);
MarkBufferDirty(buf);
UnlockReleaseBuffer(buf);
RecordPageWithFreeSpace(onerel, blkno, freespace);
continue;
}
if (PageIsEmpty(page))
{
empty_pages++;
freespace = PageGetHeapFreeSpace(page);
/* empty pages are always all-visible */
if (!PageIsAllVisible(page))
{
PageSetAllVisible(page);
MarkBufferDirty(buf);
visibilitymap_set(onerel, blkno, InvalidXLogRecPtr, vmbuffer,
InvalidTransactionId);
}
UnlockReleaseBuffer(buf);
RecordPageWithFreeSpace(onerel, blkno, freespace);
continue;
}
/*
* Prune all HOT-update chains in this page.
*
* We count tuples removed by the pruning step as removed by VACUUM.
*/
tups_vacuumed += heap_page_prune(onerel, buf, OldestXmin, false,
&vacrelstats->latestRemovedXid);
/*
* Now scan the page to collect vacuumable items and check for tuples
* requiring freezing.
*/
all_visible = true;
has_dead_tuples = false;
nfrozen = 0;
hastup = false;
prev_dead_count = vacrelstats->num_dead_tuples;
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
ItemId itemid;
itemid = PageGetItemId(page, offnum);
/* Unused items require no processing, but we count 'em */
if (!ItemIdIsUsed(itemid))
{
nunused += 1;
continue;
}
/* Redirect items mustn't be touched */
if (ItemIdIsRedirected(itemid))
{
hastup = true; /* this page won't be truncatable */
continue;
}
ItemPointerSet(&(tuple.t_self), blkno, offnum);
/*
* DEAD item pointers are to be vacuumed normally; but we don't
* count them in tups_vacuumed, else we'd be double-counting (at
* least in the common case where heap_page_prune() just freed up
* a non-HOT tuple).
*/
if (ItemIdIsDead(itemid))
{
lazy_record_dead_tuple(vacrelstats, &(tuple.t_self));
all_visible = false;
continue;
}
Assert(ItemIdIsNormal(itemid));
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
tuple.t_len = ItemIdGetLength(itemid);
tupgone = false;
switch (HeapTupleSatisfiesVacuum(tuple.t_data, OldestXmin, buf))
{
case HEAPTUPLE_DEAD:
/*
* Ordinarily, DEAD tuples would have been removed by
* heap_page_prune(), but it's possible that the tuple
* state changed since heap_page_prune() looked. In
* particular an INSERT_IN_PROGRESS tuple could have
* changed to DEAD if the inserter aborted. So this
* cannot be considered an error condition.
*
* If the tuple is HOT-updated then it must only be
* removed by a prune operation; so we keep it just as if
* it were RECENTLY_DEAD. Also, if it's a heap-only
* tuple, we choose to keep it, because it'll be a lot
* cheaper to get rid of it in the next pruning pass than
* to treat it like an indexed tuple.
*/
if (HeapTupleIsHotUpdated(&tuple) ||
HeapTupleIsHeapOnly(&tuple))
nkeep += 1;
else
tupgone = true; /* we can delete the tuple */
all_visible = false;
break;
case HEAPTUPLE_LIVE:
/* Tuple is good --- but let's do some validity checks */
if (onerel->rd_rel->relhasoids &&
!OidIsValid(HeapTupleGetOid(&tuple)))
elog(WARNING, "relation \"%s\" TID %u/%u: OID is invalid",
relname, blkno, offnum);
/*
* Is the tuple definitely visible to all transactions?
*
* NB: Like with per-tuple hint bits, we can't set the
* PD_ALL_VISIBLE flag if the inserter committed
* asynchronously. See SetHintBits for more info. Check
* that the HEAP_XMIN_COMMITTED hint bit is set because of
* that.
*/
if (all_visible)
{
TransactionId xmin;
if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
{
all_visible = false;
break;
}
/*
* The inserter definitely committed. But is it old
* enough that everyone sees it as committed?
*/
xmin = HeapTupleHeaderGetXmin(tuple.t_data);
if (!TransactionIdPrecedes(xmin, OldestXmin))
{
all_visible = false;
break;
}
/* Track newest xmin on page. */
if (TransactionIdFollows(xmin, visibility_cutoff_xid))
visibility_cutoff_xid = xmin;
}
break;
case HEAPTUPLE_RECENTLY_DEAD:
/*
* If tuple is recently deleted then we must not remove it
* from relation.
*/
nkeep += 1;
all_visible = false;
break;
case HEAPTUPLE_INSERT_IN_PROGRESS:
/* This is an expected case during concurrent vacuum */
all_visible = false;
break;
case HEAPTUPLE_DELETE_IN_PROGRESS:
/* This is an expected case during concurrent vacuum */
all_visible = false;
break;
default:
elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
break;
}
if (tupgone)
{
lazy_record_dead_tuple(vacrelstats, &(tuple.t_self));
HeapTupleHeaderAdvanceLatestRemovedXid(tuple.t_data,
&vacrelstats->latestRemovedXid);
tups_vacuumed += 1;
has_dead_tuples = true;
}
else
{
num_tuples += 1;
hastup = true;
/*
* Each non-removable tuple must be checked to see if it needs
* freezing. Note we already have exclusive buffer lock.
*/
if (heap_freeze_tuple(tuple.t_data, FreezeLimit))
frozen[nfrozen++] = offnum;
}
} /* scan along page */
/*
* If we froze any tuples, mark the buffer dirty, and write a WAL
* record recording the changes. We must log the changes to be
* crash-safe against future truncation of CLOG.
*/
if (nfrozen > 0)
{
MarkBufferDirty(buf);
if (RelationNeedsWAL(onerel))
{
XLogRecPtr recptr;
recptr = log_heap_freeze(onerel, buf, FreezeLimit,
frozen, nfrozen);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
}
/*
* If there are no indexes then we can vacuum the page right now
* instead of doing a second scan.
*/
if (nindexes == 0 &&
vacrelstats->num_dead_tuples > 0)
{
/* Remove tuples from heap */
lazy_vacuum_page(onerel, blkno, buf, 0, vacrelstats);
/*
* Forget the now-vacuumed tuples, and press on, but be careful
* not to reset latestRemovedXid since we want that value to be
* valid.
*/
vacrelstats->num_dead_tuples = 0;
vacuumed_pages++;
}
freespace = PageGetHeapFreeSpace(page);
/* mark page all-visible, if appropriate */
if (all_visible)
{
if (!PageIsAllVisible(page))
{
PageSetAllVisible(page);
MarkBufferDirty(buf);
visibilitymap_set(onerel, blkno, InvalidXLogRecPtr, vmbuffer,
visibility_cutoff_xid);
}
else if (!all_visible_according_to_vm)
{
/*
* 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. Set the visibility map bit as well so that we get
* back in sync.
*/
visibilitymap_set(onerel, blkno, InvalidXLogRecPtr, vmbuffer,
visibility_cutoff_xid);
}
}
/*
* As of PostgreSQL 9.2, the visibility map bit should never be set if
* the page-level bit is clear. However, it's possible that the bit
* got cleared after we checked it and before we took the buffer
* content lock, so we must recheck before jumping to the conclusion
* that something bad has happened.
*/
else if (all_visible_according_to_vm && !PageIsAllVisible(page)
&& visibilitymap_test(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);
}
/*
* It's possible for the value returned by GetOldestXmin() to move
* backwards, so it's not wrong for us to see tuples that appear to
* not be visible to everyone yet, while PD_ALL_VISIBLE is already
* set. The real safe xmin value never moves backwards, but
* GetOldestXmin() is conservative and sometimes returns a value
* that's unnecessarily small, so if we see that contradiction it just
* means that the tuples that we think are not visible to everyone yet
* actually are, and the PD_ALL_VISIBLE flag is correct.
*
* There should never be dead tuples on a page with PD_ALL_VISIBLE
* set, however.
*/
else if (PageIsAllVisible(page) && has_dead_tuples)
{
elog(WARNING, "page containing dead tuples is marked as all-visible in relation \"%s\" page %u",
relname, blkno);
PageClearAllVisible(page);
MarkBufferDirty(buf);
visibilitymap_clear(onerel, blkno, vmbuffer);
}
UnlockReleaseBuffer(buf);
/* Remember the location of the last page with nonremovable tuples */
if (hastup)
vacrelstats->nonempty_pages = blkno + 1;
/*
* If we remembered any tuples for deletion, then the page will be
* visited again by lazy_vacuum_heap, which will compute and record
* its post-compaction free space. If not, then we're done with this
* page, so remember its free space as-is. (This path will always be
* taken if there are no indexes.)
*/
if (vacrelstats->num_dead_tuples == prev_dead_count)
RecordPageWithFreeSpace(onerel, blkno, freespace);
}
/* save stats for use later */
vacrelstats->scanned_tuples = num_tuples;
vacrelstats->tuples_deleted = tups_vacuumed;
/* now we can compute the new value for pg_class.reltuples */
vacrelstats->new_rel_tuples = vac_estimate_reltuples(onerel, false,
nblocks,
vacrelstats->scanned_pages,
num_tuples);
/*
* Release any remaining pin on visibility map page.
*/
if (BufferIsValid(vmbuffer))
{
ReleaseBuffer(vmbuffer);
vmbuffer = InvalidBuffer;
}
/* If any tuples need to be deleted, perform final vacuum cycle */
/* XXX put a threshold on min number of tuples here? */
if (vacrelstats->num_dead_tuples > 0)
{
/* Log cleanup info before we touch indexes */
vacuum_log_cleanup_info(onerel, vacrelstats);
/* Remove index entries */
for (i = 0; i < nindexes; i++)
lazy_vacuum_index(Irel[i],
&indstats[i],
vacrelstats);
/* Remove tuples from heap */
lazy_vacuum_heap(onerel, vacrelstats);
vacrelstats->num_index_scans++;
}
/* Do post-vacuum cleanup and statistics update for each index */
for (i = 0; i < nindexes; i++)
lazy_cleanup_index(Irel[i], indstats[i], vacrelstats);
/* If no indexes, make log report that lazy_vacuum_heap would've made */
if (vacuumed_pages)
ereport(elevel,
(errmsg("\"%s\": removed %.0f row versions in %u pages",
RelationGetRelationName(onerel),
tups_vacuumed, vacuumed_pages)));
ereport(elevel,
(errmsg("\"%s\": found %.0f removable, %.0f nonremovable row versions in %u out of %u pages",
RelationGetRelationName(onerel),
tups_vacuumed, num_tuples,
vacrelstats->scanned_pages, nblocks),
errdetail("%.0f dead row versions cannot be removed yet.\n"
"There were %.0f unused item pointers.\n"
"%u pages are entirely empty.\n"
"%s.",
nkeep,
nunused,
empty_pages,
pg_rusage_show(&ru0))));
}
/*
* VACUUM cleanup: update FSM
*/
IndexBulkDeleteResult *
gistvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
{
Relation rel = info->index;
BlockNumber npages,
blkno;
BlockNumber totFreePages;
bool needLock;
/* No-op in ANALYZE ONLY mode */
if (info->analyze_only)
return stats;
/* Set up all-zero stats if gistbulkdelete wasn't called */
if (stats == NULL)
{
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
/* use heap's tuple count */
stats->num_index_tuples = info->num_heap_tuples;
stats->estimated_count = info->estimated_count;
/*
* XXX the above is wrong if index is partial. Would it be OK to just
* return NULL, or is there work we must do below?
*/
}
/*
* Need lock unless it's local to this backend.
*/
needLock = !RELATION_IS_LOCAL(rel);
/* try to find deleted pages */
if (needLock)
LockRelationForExtension(rel, ExclusiveLock);
npages = RelationGetNumberOfBlocks(rel);
if (needLock)
UnlockRelationForExtension(rel, ExclusiveLock);
totFreePages = 0;
for (blkno = GIST_ROOT_BLKNO + 1; blkno < npages; blkno++)
{
Buffer buffer;
Page page;
vacuum_delay_point();
buffer = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL,
info->strategy);
LockBuffer(buffer, GIST_SHARE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew(page) || GistPageIsDeleted(page))
{
totFreePages++;
RecordFreeIndexPage(rel, blkno);
}
UnlockReleaseBuffer(buffer);
}
/* Finally, vacuum the FSM */
IndexFreeSpaceMapVacuum(info->index);
/* return statistics */
stats->pages_free = totFreePages;
if (needLock)
LockRelationForExtension(rel, ExclusiveLock);
stats->num_pages = RelationGetNumberOfBlocks(rel);
if (needLock)
UnlockRelationForExtension(rel, ExclusiveLock);
return stats;
}
/*
* Bulk deletion of all index entries pointing to a set of heap tuples.
* The set of target tuples is specified via a callback routine that tells
* whether any given heap tuple (identified by ItemPointer) is being deleted.
*
* This function also deletes the tuples that are moved by split to other
* bucket.
*
* Result: a palloc'd struct containing statistical info for VACUUM displays.
*/
IndexBulkDeleteResult *
hashbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback, void *callback_state)
{
Relation rel = info->index;
double tuples_removed;
double num_index_tuples;
double orig_ntuples;
Bucket orig_maxbucket;
Bucket cur_maxbucket;
Bucket cur_bucket;
Buffer metabuf = InvalidBuffer;
HashMetaPage metap;
HashMetaPage cachedmetap;
tuples_removed = 0;
num_index_tuples = 0;
/*
* We need a copy of the metapage so that we can use its hashm_spares[]
* values to compute bucket page addresses, but a cached copy should be
* good enough. (If not, we'll detect that further down and refresh the
* cache as necessary.)
*/
cachedmetap = _hash_getcachedmetap(rel, &metabuf, false);
Assert(cachedmetap != NULL);
orig_maxbucket = cachedmetap->hashm_maxbucket;
orig_ntuples = cachedmetap->hashm_ntuples;
/* Scan the buckets that we know exist */
cur_bucket = 0;
cur_maxbucket = orig_maxbucket;
loop_top:
while (cur_bucket <= cur_maxbucket)
{
BlockNumber bucket_blkno;
BlockNumber blkno;
Buffer bucket_buf;
Buffer buf;
HashPageOpaque bucket_opaque;
Page page;
bool split_cleanup = false;
/* Get address of bucket's start page */
bucket_blkno = BUCKET_TO_BLKNO(cachedmetap, cur_bucket);
blkno = bucket_blkno;
/*
* We need to acquire a cleanup lock on the primary bucket page to out
* wait concurrent scans before deleting the dead tuples.
*/
buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, info->strategy);
LockBufferForCleanup(buf);
_hash_checkpage(rel, buf, LH_BUCKET_PAGE);
page = BufferGetPage(buf);
bucket_opaque = (HashPageOpaque) PageGetSpecialPointer(page);
/*
* If the bucket contains tuples that are moved by split, then we need
* to delete such tuples. We can't delete such tuples if the split
* operation on bucket is not finished as those are needed by scans.
*/
if (!H_BUCKET_BEING_SPLIT(bucket_opaque) &&
H_NEEDS_SPLIT_CLEANUP(bucket_opaque))
{
split_cleanup = true;
/*
* This bucket might have been split since we last held a lock on
* the metapage. If so, hashm_maxbucket, hashm_highmask and
* hashm_lowmask might be old enough to cause us to fail to remove
* tuples left behind by the most recent split. To prevent that,
* now that the primary page of the target bucket has been locked
* (and thus can't be further split), check whether we need to
* update our cached metapage data.
*
* NB: The check for InvalidBlockNumber is only needed for
* on-disk compatibility with indexes created before we started
* storing hashm_maxbucket in the primary page's hasho_prevblkno.
*/
if (bucket_opaque->hasho_prevblkno != InvalidBlockNumber &&
bucket_opaque->hasho_prevblkno > cachedmetap->hashm_maxbucket)
{
cachedmetap = _hash_getcachedmetap(rel, &metabuf, true);
Assert(cachedmetap != NULL);
}
}
bucket_buf = buf;
hashbucketcleanup(rel, cur_bucket, bucket_buf, blkno, info->strategy,
cachedmetap->hashm_maxbucket,
cachedmetap->hashm_highmask,
cachedmetap->hashm_lowmask, &tuples_removed,
&num_index_tuples, split_cleanup,
callback, callback_state);
_hash_dropbuf(rel, bucket_buf);
/* Advance to next bucket */
cur_bucket++;
}
if (BufferIsInvalid(metabuf))
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_NOLOCK, LH_META_PAGE);
/* Write-lock metapage and check for split since we started */
LockBuffer(metabuf, BUFFER_LOCK_EXCLUSIVE);
metap = HashPageGetMeta(BufferGetPage(metabuf));
if (cur_maxbucket != metap->hashm_maxbucket)
{
/* There's been a split, so process the additional bucket(s) */
LockBuffer(metabuf, BUFFER_LOCK_UNLOCK);
cachedmetap = _hash_getcachedmetap(rel, &metabuf, true);
Assert(cachedmetap != NULL);
cur_maxbucket = cachedmetap->hashm_maxbucket;
goto loop_top;
}
/* Okay, we're really done. Update tuple count in metapage. */
START_CRIT_SECTION();
if (orig_maxbucket == metap->hashm_maxbucket &&
orig_ntuples == metap->hashm_ntuples)
{
/*
* No one has split or inserted anything since start of scan, so
* believe our count as gospel.
*/
metap->hashm_ntuples = num_index_tuples;
}
else
{
/*
* Otherwise, our count is untrustworthy since we may have
* double-scanned tuples in split buckets. Proceed by dead-reckoning.
* (Note: we still return estimated_count = false, because using this
* count is better than not updating reltuples at all.)
*/
if (metap->hashm_ntuples > tuples_removed)
metap->hashm_ntuples -= tuples_removed;
else
metap->hashm_ntuples = 0;
num_index_tuples = metap->hashm_ntuples;
}
MarkBufferDirty(metabuf);
/* XLOG stuff */
if (RelationNeedsWAL(rel))
{
xl_hash_update_meta_page xlrec;
XLogRecPtr recptr;
xlrec.ntuples = metap->hashm_ntuples;
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(SizeOfHashUpdateMetaPage));
XLogRegisterBuffer(0, metabuf, REGBUF_STANDARD);
recptr = XLogInsert(RM_HASH_ID, XLOG_HASH_UPDATE_META_PAGE);
PageSetLSN(BufferGetPage(metabuf), recptr);
}
END_CRIT_SECTION();
_hash_relbuf(rel, metabuf);
/* return statistics */
if (stats == NULL)
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
stats->estimated_count = false;
stats->num_index_tuples = num_index_tuples;
stats->tuples_removed += tuples_removed;
/* hashvacuumcleanup will fill in num_pages */
return stats;
}
/*
* Read a FSM page.
*
* If the page doesn't exist, InvalidBuffer is returned, or if 'extend' is
* true, the FSM file is extended.
*/
static Buffer
fsm_readbuf(Relation rel, FSMAddress addr, bool extend)
{
BlockNumber blkno = fsm_logical_to_physical(addr);
Buffer buf;
RelationOpenSmgr(rel);
/*
* If we haven't cached the size of the FSM yet, check it first. Also
* recheck if the requested block seems to be past end, since our cached
* value might be stale. (We send smgr inval messages on truncation, but
* not on extension.)
*/
if (rel->rd_smgr->smgr_fsm_nblocks == InvalidBlockNumber ||
blkno >= rel->rd_smgr->smgr_fsm_nblocks)
{
if (smgrexists(rel->rd_smgr, FSM_FORKNUM))
rel->rd_smgr->smgr_fsm_nblocks = smgrnblocks(rel->rd_smgr,
FSM_FORKNUM);
else
rel->rd_smgr->smgr_fsm_nblocks = 0;
}
/* Handle requests beyond EOF */
if (blkno >= rel->rd_smgr->smgr_fsm_nblocks)
{
if (extend)
fsm_extend(rel, blkno + 1);
else
return InvalidBuffer;
}
/*
* Use ZERO_ON_ERROR mode, and initialize the page if necessary. The FSM
* information is not accurate anyway, so it's better to clear corrupt
* pages than error out. Since the FSM changes are not WAL-logged, the
* so-called torn page problem on crash can lead to pages with corrupt
* headers, for example.
*
* The initialize-the-page part is trickier than it looks, because of the
* possibility of multiple backends doing this concurrently, and our
* desire to not uselessly take the buffer lock in the normal path where
* the page is OK. We must take the lock to initialize the page, so
* recheck page newness after we have the lock, in case someone else
* already did it. Also, because we initially check PageIsNew with no
* lock, it's possible to fall through and return the buffer while someone
* else is still initializing the page (i.e., we might see pd_upper as set
* but other page header fields are still zeroes). This is harmless for
* callers that will take a buffer lock themselves, but some callers
* inspect the page without any lock at all. The latter is OK only so
* long as it doesn't depend on the page header having correct contents.
* Current usage is safe because PageGetContents() does not require that.
*/
buf = ReadBufferExtended(rel, FSM_FORKNUM, blkno, RBM_ZERO_ON_ERROR, NULL);
if (PageIsNew(BufferGetPage(buf)))
{
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
if (PageIsNew(BufferGetPage(buf)))
PageInit(BufferGetPage(buf), BLCKSZ, 0);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
return buf;
}
/*
* Delete a posting tree page.
*/
static void
ginDeletePage(GinVacuumState *gvs, BlockNumber deleteBlkno, BlockNumber leftBlkno,
BlockNumber parentBlkno, OffsetNumber myoff, bool isParentRoot)
{
Buffer dBuffer;
Buffer lBuffer;
Buffer pBuffer;
Page page,
parentPage;
BlockNumber rightlink;
/*
* Lock the pages in the same order as an insertion would, to avoid
* deadlocks: left, then right, then parent.
*/
lBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, leftBlkno,
RBM_NORMAL, gvs->strategy);
dBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, deleteBlkno,
RBM_NORMAL, gvs->strategy);
pBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, parentBlkno,
RBM_NORMAL, gvs->strategy);
LockBuffer(lBuffer, GIN_EXCLUSIVE);
LockBuffer(dBuffer, GIN_EXCLUSIVE);
if (!isParentRoot) /* parent is already locked by
* LockBufferForCleanup() */
LockBuffer(pBuffer, GIN_EXCLUSIVE);
START_CRIT_SECTION();
/* Unlink the page by changing left sibling's rightlink */
page = BufferGetPage(dBuffer);
rightlink = GinPageGetOpaque(page)->rightlink;
page = BufferGetPage(lBuffer);
GinPageGetOpaque(page)->rightlink = rightlink;
/* Delete downlink from parent */
parentPage = BufferGetPage(pBuffer);
#ifdef USE_ASSERT_CHECKING
do
{
PostingItem *tod = GinDataPageGetPostingItem(parentPage, myoff);
Assert(PostingItemGetBlockNumber(tod) == deleteBlkno);
} while (0);
#endif
GinPageDeletePostingItem(parentPage, myoff);
page = BufferGetPage(dBuffer);
/*
* we shouldn't change rightlink field to save workability of running
* search scan
*/
GinPageGetOpaque(page)->flags = GIN_DELETED;
MarkBufferDirty(pBuffer);
MarkBufferDirty(lBuffer);
MarkBufferDirty(dBuffer);
if (RelationNeedsWAL(gvs->index))
{
XLogRecPtr recptr;
ginxlogDeletePage data;
/*
* We can't pass REGBUF_STANDARD for the deleted page, because we
* didn't set pd_lower on pre-9.4 versions. The page might've been
* binary-upgraded from an older version, and hence not have pd_lower
* set correctly. Ditto for the left page, but removing the item from
* the parent updated its pd_lower, so we know that's OK at this
* point.
*/
XLogBeginInsert();
XLogRegisterBuffer(0, dBuffer, 0);
XLogRegisterBuffer(1, pBuffer, REGBUF_STANDARD);
XLogRegisterBuffer(2, lBuffer, 0);
data.parentOffset = myoff;
data.rightLink = GinPageGetOpaque(page)->rightlink;
XLogRegisterData((char *) &data, sizeof(ginxlogDeletePage));
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_DELETE_PAGE);
PageSetLSN(page, recptr);
PageSetLSN(parentPage, recptr);
PageSetLSN(BufferGetPage(lBuffer), recptr);
}
if (!isParentRoot)
LockBuffer(pBuffer, GIN_UNLOCK);
ReleaseBuffer(pBuffer);
UnlockReleaseBuffer(lBuffer);
UnlockReleaseBuffer(dBuffer);
END_CRIT_SECTION();
gvs->result->pages_deleted++;
}
/*
* Insert all matching tuples into a bitmap.
*/
int64
blgetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
{
int64 ntids = 0;
BlockNumber blkno = BLOOM_HEAD_BLKNO,
npages;
int i;
BufferAccessStrategy bas;
BloomScanOpaque so = (BloomScanOpaque) scan->opaque;
if (so->sign == NULL)
{
/* New search: have to calculate search signature */
ScanKey skey = scan->keyData;
so->sign = palloc0(sizeof(BloomSignatureWord) * so->state.opts.bloomLength);
for (i = 0; i < scan->numberOfKeys; i++)
{
/*
* Assume bloom-indexable operators to be strict, so nothing could
* be found for NULL key.
*/
if (skey->sk_flags & SK_ISNULL)
{
pfree(so->sign);
so->sign = NULL;
return 0;
}
/* Add next value to the signature */
signValue(&so->state, so->sign, skey->sk_argument,
skey->sk_attno - 1);
skey++;
}
}
/*
* We're going to read the whole index. This is why we use appropriate
* buffer access strategy.
*/
bas = GetAccessStrategy(BAS_BULKREAD);
npages = RelationGetNumberOfBlocks(scan->indexRelation);
for (blkno = BLOOM_HEAD_BLKNO; blkno < npages; blkno++)
{
Buffer buffer;
Page page;
buffer = ReadBufferExtended(scan->indexRelation, MAIN_FORKNUM,
blkno, RBM_NORMAL, bas);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = BufferGetPage(buffer);
TestForOldSnapshot(scan->xs_snapshot, scan->indexRelation, page);
if (!PageIsNew(page) && !BloomPageIsDeleted(page))
{
OffsetNumber offset,
maxOffset = BloomPageGetMaxOffset(page);
for (offset = 1; offset <= maxOffset; offset++)
{
BloomTuple *itup = BloomPageGetTuple(&so->state, page, offset);
bool res = true;
/* Check index signature with scan signature */
for (i = 0; i < so->state.opts.bloomLength; i++)
{
if ((itup->sign[i] & so->sign[i]) != so->sign[i])
{
res = false;
break;
}
}
/* Add matching tuples to bitmap */
if (res)
{
tbm_add_tuples(tbm, &itup->heapPtr, 1, true);
ntids++;
}
}
}
UnlockReleaseBuffer(buffer);
CHECK_FOR_INTERRUPTS();
}
FreeAccessStrategy(bas);
return ntids;
}
static bool
ginVacuumPostingTreeLeaves(GinVacuumState *gvs, BlockNumber blkno, bool isRoot, Buffer *rootBuffer)
{
Buffer buffer;
Page page;
bool hasVoidPage = FALSE;
MemoryContext oldCxt;
buffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, blkno,
RBM_NORMAL, gvs->strategy);
page = BufferGetPage(buffer);
/*
* We should be sure that we don't concurrent with inserts, insert process
* never release root page until end (but it can unlock it and lock
* again). New scan can't start but previously started ones work
* concurrently.
*/
if (isRoot)
LockBufferForCleanup(buffer);
else
LockBuffer(buffer, GIN_EXCLUSIVE);
Assert(GinPageIsData(page));
if (GinPageIsLeaf(page))
{
oldCxt = MemoryContextSwitchTo(gvs->tmpCxt);
ginVacuumPostingTreeLeaf(gvs->index, buffer, gvs);
MemoryContextSwitchTo(oldCxt);
MemoryContextReset(gvs->tmpCxt);
/* if root is a leaf page, we don't desire further processing */
if (!isRoot && !hasVoidPage && GinDataLeafPageIsEmpty(page))
hasVoidPage = TRUE;
}
else
{
OffsetNumber i;
bool isChildHasVoid = FALSE;
for (i = FirstOffsetNumber; i <= GinPageGetOpaque(page)->maxoff; i++)
{
PostingItem *pitem = GinDataPageGetPostingItem(page, i);
if (ginVacuumPostingTreeLeaves(gvs, PostingItemGetBlockNumber(pitem), FALSE, NULL))
isChildHasVoid = TRUE;
}
if (isChildHasVoid)
hasVoidPage = TRUE;
}
/*
* if we have root and there are empty pages in tree, then we don't
* release lock to go further processing and guarantee that tree is unused
*/
if (!(isRoot && hasVoidPage))
{
UnlockReleaseBuffer(buffer);
}
else
{
Assert(rootBuffer);
*rootBuffer = buffer;
}
return hasVoidPage;
}
/*
* workhorse
*/
static bytea *
get_raw_page_internal(text *relname, ForkNumber forknum, BlockNumber blkno)
{
bytea *raw_page;
RangeVar *relrv;
Relation rel;
char *raw_page_data;
Buffer buf;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to use raw functions"))));
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
rel = relation_openrv(relrv, AccessShareLock);
/* Check that this relation has storage */
if (rel->rd_rel->relkind == RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot get raw page from view \"%s\"",
RelationGetRelationName(rel))));
if (rel->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot get raw page from composite type \"%s\"",
RelationGetRelationName(rel))));
/*
* Reject attempts to read non-local temporary relations; we would be
* likely to get wrong data since we have no visibility into the owning
* session's local buffers.
*/
if (RELATION_IS_OTHER_TEMP(rel))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot access temporary tables of other sessions")));
if (blkno >= RelationGetNumberOfBlocks(rel))
elog(ERROR, "block number %u is out of range for relation \"%s\"",
blkno, RelationGetRelationName(rel));
/* Initialize buffer to copy to */
raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);
SET_VARSIZE(raw_page, BLCKSZ + VARHDRSZ);
raw_page_data = VARDATA(raw_page);
/* Take a verbatim copy of the page */
buf = ReadBufferExtended(rel, forknum, blkno, RBM_NORMAL, NULL);
LockBuffer(buf, BUFFER_LOCK_SHARE);
memcpy(raw_page_data, BufferGetPage(buf), BLCKSZ);
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
ReleaseBuffer(buf);
relation_close(rel, AccessShareLock);
return raw_page;
}
/*
* VACUUM cleanup: update FSM
*/
Datum
gistvacuumcleanup(PG_FUNCTION_ARGS)
{
IndexVacuumInfo *info = (IndexVacuumInfo *) PG_GETARG_POINTER(0);
GistBulkDeleteResult *stats = (GistBulkDeleteResult *) PG_GETARG_POINTER(1);
Relation rel = info->index;
BlockNumber npages,
blkno;
BlockNumber totFreePages;
BlockNumber lastBlock = GIST_ROOT_BLKNO,
lastFilledBlock = GIST_ROOT_BLKNO;
bool needLock;
/* No-op in ANALYZE ONLY mode */
if (info->analyze_only)
PG_RETURN_POINTER(stats);
/* Set up all-zero stats if gistbulkdelete wasn't called */
if (stats == NULL)
{
stats = (GistBulkDeleteResult *) palloc0(sizeof(GistBulkDeleteResult));
/* use heap's tuple count */
stats->std.num_index_tuples = info->num_heap_tuples;
stats->std.estimated_count = info->estimated_count;
/*
* XXX the above is wrong if index is partial. Would it be OK to just
* return NULL, or is there work we must do below?
*/
}
if (stats->needReindex)
ereport(NOTICE,
(errmsg("index \"%s\" needs VACUUM FULL or REINDEX to finish crash recovery",
RelationGetRelationName(rel))));
/*
* Need lock unless it's local to this backend.
*/
needLock = !RELATION_IS_LOCAL(rel);
/* try to find deleted pages */
if (needLock)
LockRelationForExtension(rel, ExclusiveLock);
npages = RelationGetNumberOfBlocks(rel);
if (needLock)
UnlockRelationForExtension(rel, ExclusiveLock);
totFreePages = 0;
for (blkno = GIST_ROOT_BLKNO + 1; blkno < npages; blkno++)
{
Buffer buffer;
Page page;
vacuum_delay_point();
buffer = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL,
info->strategy);
LockBuffer(buffer, GIST_SHARE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew(page) || GistPageIsDeleted(page))
{
totFreePages++;
RecordFreeIndexPage(rel, blkno);
}
else
lastFilledBlock = blkno;
UnlockReleaseBuffer(buffer);
}
lastBlock = npages - 1;
/* Finally, vacuum the FSM */
IndexFreeSpaceMapVacuum(info->index);
/* return statistics */
stats->std.pages_free = totFreePages;
if (needLock)
LockRelationForExtension(rel, ExclusiveLock);
stats->std.num_pages = RelationGetNumberOfBlocks(rel);
if (needLock)
UnlockRelationForExtension(rel, ExclusiveLock);
PG_RETURN_POINTER(stats);
}
/*
* pg_prewarm(regclass, mode text, fork text,
* first_block int8, last_block int8)
*
* The first argument is the relation to be prewarmed; the second controls
* how prewarming is done; legal options are 'prefetch', 'read', and 'buffer'.
* The third is the name of the relation fork to be prewarmed. The fourth
* and fifth arguments specify the first and last block to be prewarmed.
* If the fourth argument is NULL, it will be taken as 0; if the fifth argument
* is NULL, it will be taken as the number of blocks in the relation. The
* return value is the number of blocks successfully prewarmed.
*/
Datum
pg_prewarm(PG_FUNCTION_ARGS)
{
Oid relOid;
text *forkName;
text *type;
int64 first_block;
int64 last_block;
int64 nblocks;
int64 blocks_done = 0;
int64 block;
Relation rel;
ForkNumber forkNumber;
char *forkString;
char *ttype;
PrewarmType ptype;
AclResult aclresult;
/* Basic sanity checking. */
if (PG_ARGISNULL(0))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("relation cannot be null")));
relOid = PG_GETARG_OID(0);
if (PG_ARGISNULL(1))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
(errmsg("prewarm type cannot be null"))));
type = PG_GETARG_TEXT_P(1);
ttype = text_to_cstring(type);
if (strcmp(ttype, "prefetch") == 0)
ptype = PREWARM_PREFETCH;
else if (strcmp(ttype, "read") == 0)
ptype = PREWARM_READ;
else if (strcmp(ttype, "buffer") == 0)
ptype = PREWARM_BUFFER;
else
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid prewarm type"),
errhint("Valid prewarm types are \"prefetch\", \"read\", and \"buffer\".")));
PG_RETURN_INT64(0); /* Placate compiler. */
}
if (PG_ARGISNULL(2))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
(errmsg("relation fork cannot be null"))));
forkName = PG_GETARG_TEXT_P(2);
forkString = text_to_cstring(forkName);
forkNumber = forkname_to_number(forkString);
/* Open relation and check privileges. */
rel = relation_open(relOid, AccessShareLock);
aclresult = pg_class_aclcheck(relOid, GetUserId(), ACL_SELECT);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS, get_rel_name(relOid));
/* Check that the fork exists. */
RelationOpenSmgr(rel);
if (!smgrexists(rel->rd_smgr, forkNumber))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("fork \"%s\" does not exist for this relation",
forkString)));
/* Validate block numbers, or handle nulls. */
nblocks = RelationGetNumberOfBlocksInFork(rel, forkNumber);
if (PG_ARGISNULL(3))
first_block = 0;
else
{
first_block = PG_GETARG_INT64(3);
if (first_block < 0 || first_block >= nblocks)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("starting block number must be between 0 and " INT64_FORMAT,
nblocks - 1)));
}
if (PG_ARGISNULL(4))
last_block = nblocks - 1;
else
{
last_block = PG_GETARG_INT64(4);
if (last_block < 0 || last_block >= nblocks)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("ending block number must be between 0 and " INT64_FORMAT,
nblocks - 1)));
}
/* Now we're ready to do the real work. */
if (ptype == PREWARM_PREFETCH)
{
#ifdef USE_PREFETCH
/*
* In prefetch mode, we just hint the OS to read the blocks, but we
* don't know whether it really does it, and we don't wait for it to
* finish.
*
* It would probably be better to pass our prefetch requests in chunks
* of a megabyte or maybe even a whole segment at a time, but there's
* no practical way to do that at present without a gross modularity
* violation, so we just do this.
*/
for (block = first_block; block <= last_block; ++block)
{
CHECK_FOR_INTERRUPTS();
PrefetchBuffer(rel, forkNumber, block);
++blocks_done;
}
#else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("prefetch is not supported by this build")));
#endif
}
else if (ptype == PREWARM_READ)
{
/*
* In read mode, we actually read the blocks, but not into shared
* buffers. This is more portable than prefetch mode (it works
* everywhere) and is synchronous.
*/
for (block = first_block; block <= last_block; ++block)
{
CHECK_FOR_INTERRUPTS();
smgrread(rel->rd_smgr, forkNumber, block, blockbuffer);
++blocks_done;
}
}
else if (ptype == PREWARM_BUFFER)
{
/*
* In buffer mode, we actually pull the data into shared_buffers.
*/
for (block = first_block; block <= last_block; ++block)
{
Buffer buf;
CHECK_FOR_INTERRUPTS();
buf = ReadBufferExtended(rel, forkNumber, block, RBM_NORMAL, NULL);
ReleaseBuffer(buf);
++blocks_done;
}
}
/* Close relation, release lock. */
relation_close(rel, AccessShareLock);
PG_RETURN_INT64(blocks_done);
}
/*
* This function takes an already open relation and scans its pages,
* skipping those that have the corresponding visibility map bit set.
* For pages we skip, we find the free space from the free space map
* and approximate tuple_len on that basis. For the others, we count
* the exact number of dead tuples etc.
*
* This scan is loosely based on vacuumlazy.c:lazy_scan_heap(), but
* we do not try to avoid skipping single pages.
*/
static void
statapprox_heap(Relation rel, output_type *stat)
{
BlockNumber scanned,
nblocks,
blkno;
Buffer vmbuffer = InvalidBuffer;
BufferAccessStrategy bstrategy;
TransactionId OldestXmin;
uint64 misc_count = 0;
OldestXmin = GetOldestXmin(rel, true);
bstrategy = GetAccessStrategy(BAS_BULKREAD);
nblocks = RelationGetNumberOfBlocks(rel);
scanned = 0;
for (blkno = 0; blkno < nblocks; blkno++)
{
Buffer buf;
Page page;
OffsetNumber offnum,
maxoff;
Size freespace;
CHECK_FOR_INTERRUPTS();
/*
* If the page has only visible tuples, then we can find out the
* free space from the FSM and move on.
*/
if (visibilitymap_test(rel, blkno, &vmbuffer))
{
freespace = GetRecordedFreeSpace(rel, blkno);
stat->tuple_len += BLCKSZ - freespace;
stat->free_space += freespace;
continue;
}
buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno,
RBM_NORMAL, bstrategy);
LockBuffer(buf, BUFFER_LOCK_SHARE);
page = BufferGetPage(buf);
/*
* It's not safe to call PageGetHeapFreeSpace() on new pages, so
* we treat them as being free space for our purposes.
*/
if (!PageIsNew(page))
stat->free_space += PageGetHeapFreeSpace(page);
else
stat->free_space += BLCKSZ - SizeOfPageHeaderData;
if (PageIsNew(page) || PageIsEmpty(page))
{
UnlockReleaseBuffer(buf);
continue;
}
scanned++;
/*
* Look at each tuple on the page and decide whether it's live
* or dead, then count it and its size. Unlike lazy_scan_heap,
* we can afford to ignore problems and special cases.
*/
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
ItemId itemid;
HeapTupleData tuple;
itemid = PageGetItemId(page, offnum);
if (!ItemIdIsUsed(itemid) || ItemIdIsRedirected(itemid) ||
ItemIdIsDead(itemid))
{
continue;
}
Assert(ItemIdIsNormal(itemid));
ItemPointerSet(&(tuple.t_self), blkno, offnum);
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
tuple.t_len = ItemIdGetLength(itemid);
tuple.t_tableOid = RelationGetRelid(rel);
/*
* We count live and dead tuples, but we also need to add up
* others in order to feed vac_estimate_reltuples.
*/
switch (HeapTupleSatisfiesVacuum(&tuple, OldestXmin, buf))
{
case HEAPTUPLE_RECENTLY_DEAD:
misc_count++;
/* Fall through */
case HEAPTUPLE_DEAD:
stat->dead_tuple_len += tuple.t_len;
stat->dead_tuple_count++;
break;
case HEAPTUPLE_LIVE:
stat->tuple_len += tuple.t_len;
stat->tuple_count++;
break;
case HEAPTUPLE_INSERT_IN_PROGRESS:
case HEAPTUPLE_DELETE_IN_PROGRESS:
misc_count++;
break;
default:
elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
break;
}
}
UnlockReleaseBuffer(buf);
}
stat->table_len = (uint64) nblocks * BLCKSZ;
stat->tuple_count = vac_estimate_reltuples(rel, false, nblocks, scanned,
stat->tuple_count+misc_count);
/*
* Calculate percentages if the relation has one or more pages.
*/
if (nblocks != 0)
{
stat->scanned_percent = 100 * scanned / nblocks;
stat->tuple_percent = 100.0 * stat->tuple_len / stat->table_len;
stat->dead_tuple_percent = 100.0 * stat->dead_tuple_len / stat->table_len;
stat->free_percent = 100.0 * stat->free_space / stat->table_len;
}
if (BufferIsValid(vmbuffer))
{
ReleaseBuffer(vmbuffer);
vmbuffer = InvalidBuffer;
}
}
/*
* Rescan end pages to verify that they are (still) empty of tuples.
*
* Returns number of nondeletable pages (last nonempty page + 1).
*/
static BlockNumber
count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
{
BlockNumber blkno;
instr_time starttime;
instr_time currenttime;
instr_time elapsed;
/* Initialize the starttime if we check for conflicting lock requests */
INSTR_TIME_SET_CURRENT(starttime);
/* Strange coding of loop control is needed because blkno is unsigned */
blkno = vacrelstats->rel_pages;
while (blkno > vacrelstats->nonempty_pages)
{
Buffer buf;
Page page;
OffsetNumber offnum,
maxoff;
bool hastup;
/*
* Check if another process requests a lock on our relation. We are
* holding an AccessExclusiveLock here, so they will be waiting. We
* only do this in autovacuum_truncate_lock_check millisecond
* intervals, and we only check if that interval has elapsed once
* every 32 blocks to keep the number of system calls and actual
* shared lock table lookups to a minimum.
*/
if ((blkno % 32) == 0)
{
INSTR_TIME_SET_CURRENT(currenttime);
elapsed = currenttime;
INSTR_TIME_SUBTRACT(elapsed, starttime);
if ((INSTR_TIME_GET_MICROSEC(elapsed) / 1000)
>= AUTOVACUUM_TRUNCATE_LOCK_CHECK_INTERVAL)
{
if (LockHasWaitersRelation(onerel, AccessExclusiveLock))
{
ereport(elevel,
(errmsg("\"%s\": suspending truncate "
"due to conflicting lock request",
RelationGetRelationName(onerel))));
vacrelstats->lock_waiter_detected = true;
return blkno;
}
starttime = currenttime;
}
}
/*
* We don't insert a vacuum delay point here, because we have an
* exclusive lock on the table which we want to hold for as short a
* time as possible. We still need to check for interrupts however.
*/
CHECK_FOR_INTERRUPTS();
blkno--;
buf = ReadBufferExtended(onerel, MAIN_FORKNUM, blkno,
RBM_NORMAL, vac_strategy);
/* In this phase we only need shared access to the buffer */
LockBuffer(buf, BUFFER_LOCK_SHARE);
page = BufferGetPage(buf);
if (PageIsNew(page) || PageIsEmpty(page))
{
/* PageIsNew probably shouldn't happen... */
UnlockReleaseBuffer(buf);
continue;
}
hastup = false;
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
ItemId itemid;
itemid = PageGetItemId(page, offnum);
/*
* Note: any non-unused item should be taken as a reason to keep
* this page. We formerly thought that DEAD tuples could be
* thrown away, but that's not so, because we'd not have cleaned
* out their index entries.
*/
if (ItemIdIsUsed(itemid))
{
hastup = true;
break; /* can stop scanning */
}
} /* scan along page */
UnlockReleaseBuffer(buf);
/* Done scanning if we found a tuple here */
if (hastup)
return blkno + 1;
}
/*
* If we fall out of the loop, all the previously-thought-to-be-empty
* pages still are; we need not bother to look at the last known-nonempty
* page.
*/
return vacrelstats->nonempty_pages;
}
static bool
ginVacuumPostingTreeLeaves(GinVacuumState *gvs, BlockNumber blkno, bool isRoot, Buffer *rootBuffer)
{
Buffer buffer;
Page page;
bool hasVoidPage = FALSE;
buffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, blkno,
RBM_NORMAL, gvs->strategy);
page = BufferGetPage(buffer);
/*
* We should be sure that we don't concurrent with inserts, insert process
* never release root page until end (but it can unlock it and lock
* again). New scan can't start but previously started ones work
* concurrently.
*/
if (isRoot)
LockBufferForCleanup(buffer);
else
LockBuffer(buffer, GIN_EXCLUSIVE);
Assert(GinPageIsData(page));
if (GinPageIsLeaf(page))
{
OffsetNumber newMaxOff,
oldMaxOff = GinPageGetOpaque(page)->maxoff;
ItemPointerData *cleaned = NULL;
newMaxOff = ginVacuumPostingList(gvs,
(ItemPointer) GinDataPageGetData(page), oldMaxOff, &cleaned);
/* saves changes about deleted tuple ... */
if (oldMaxOff != newMaxOff)
{
START_CRIT_SECTION();
if (newMaxOff > 0)
memcpy(GinDataPageGetData(page), cleaned, sizeof(ItemPointerData) * newMaxOff);
pfree(cleaned);
GinPageGetOpaque(page)->maxoff = newMaxOff;
MarkBufferDirty(buffer);
xlogVacuumPage(gvs->index, buffer);
END_CRIT_SECTION();
/* if root is a leaf page, we don't desire further processing */
if (!isRoot && GinPageGetOpaque(page)->maxoff < FirstOffsetNumber)
hasVoidPage = TRUE;
}
}
else
{
OffsetNumber i;
bool isChildHasVoid = FALSE;
for (i = FirstOffsetNumber; i <= GinPageGetOpaque(page)->maxoff; i++)
{
PostingItem *pitem = (PostingItem *) GinDataPageGetItem(page, i);
if (ginVacuumPostingTreeLeaves(gvs, PostingItemGetBlockNumber(pitem), FALSE, NULL))
isChildHasVoid = TRUE;
}
if (isChildHasVoid)
hasVoidPage = TRUE;
}
/*
* if we have root and theres void pages in tree, then we don't release
* lock to go further processing and guarantee that tree is unused
*/
if (!(isRoot && hasVoidPage))
{
UnlockReleaseBuffer(buffer);
}
else
{
Assert(rootBuffer);
*rootBuffer = buffer;
}
return hasVoidPage;
}
/*
* Bulk deletion of all index entries pointing to a set of heap tuples and
* check invalid tuples left after upgrade.
* The set of target tuples is specified via a callback routine that tells
* whether any given heap tuple (identified by ItemPointer) is being deleted.
*
* Result: a palloc'd struct containing statistical info for VACUUM displays.
*/
IndexBulkDeleteResult *
gistbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback, void *callback_state)
{
Relation rel = info->index;
GistBDItem *stack,
*ptr;
/* first time through? */
if (stats == NULL)
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
/* we'll re-count the tuples each time */
stats->estimated_count = false;
stats->num_index_tuples = 0;
stack = (GistBDItem *) palloc0(sizeof(GistBDItem));
stack->blkno = GIST_ROOT_BLKNO;
while (stack)
{
Buffer buffer;
Page page;
OffsetNumber i,
maxoff;
IndexTuple idxtuple;
ItemId iid;
buffer = ReadBufferExtended(rel, MAIN_FORKNUM, stack->blkno,
RBM_NORMAL, info->strategy);
LockBuffer(buffer, GIST_SHARE);
gistcheckpage(rel, buffer);
page = (Page) BufferGetPage(buffer);
if (GistPageIsLeaf(page))
{
OffsetNumber todelete[MaxOffsetNumber];
int ntodelete = 0;
LockBuffer(buffer, GIST_UNLOCK);
LockBuffer(buffer, GIST_EXCLUSIVE);
page = (Page) BufferGetPage(buffer);
if (stack->blkno == GIST_ROOT_BLKNO && !GistPageIsLeaf(page))
{
/* only the root can become non-leaf during relock */
UnlockReleaseBuffer(buffer);
/* one more check */
continue;
}
/*
* check for split proceeded after look at parent, we should check
* it after relock
*/
pushStackIfSplited(page, stack);
/*
* Remove deletable tuples from page
*/
maxoff = PageGetMaxOffsetNumber(page);
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
iid = PageGetItemId(page, i);
idxtuple = (IndexTuple) PageGetItem(page, iid);
if (callback(&(idxtuple->t_tid), callback_state))
todelete[ntodelete++] = i;
else
stats->num_index_tuples += 1;
}
stats->tuples_removed += ntodelete;
if (ntodelete)
{
START_CRIT_SECTION();
MarkBufferDirty(buffer);
PageIndexMultiDelete(page, todelete, ntodelete);
GistMarkTuplesDeleted(page);
if (RelationNeedsWAL(rel))
{
XLogRecPtr recptr;
recptr = gistXLogUpdate(rel->rd_node, buffer,
todelete, ntodelete,
NULL, 0, InvalidBuffer);
PageSetLSN(page, recptr);
}
else
PageSetLSN(page, gistGetFakeLSN(rel));
END_CRIT_SECTION();
}
}
else
{
/* check for split proceeded after look at parent */
pushStackIfSplited(page, stack);
maxoff = PageGetMaxOffsetNumber(page);
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
iid = PageGetItemId(page, i);
idxtuple = (IndexTuple) PageGetItem(page, iid);
ptr = (GistBDItem *) palloc(sizeof(GistBDItem));
ptr->blkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
ptr->parentlsn = PageGetLSN(page);
ptr->next = stack->next;
stack->next = ptr;
if (GistTupleIsInvalid(idxtuple))
ereport(LOG,
(errmsg("index \"%s\" contains an inner tuple marked as invalid",
RelationGetRelationName(rel)),
errdetail("This is caused by an incomplete page split at crash recovery before upgrading to PostgreSQL 9.1."),
errhint("Please REINDEX it.")));
}
}
UnlockReleaseBuffer(buffer);
ptr = stack->next;
pfree(stack);
stack = ptr;
vacuum_delay_point();
}
return stats;
}
static void
ginDeletePage(GinVacuumState *gvs, BlockNumber deleteBlkno, BlockNumber leftBlkno,
BlockNumber parentBlkno, OffsetNumber myoff, bool isParentRoot)
{
Buffer dBuffer;
Buffer lBuffer;
Buffer pBuffer;
Page page,
parentPage;
dBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, deleteBlkno,
RBM_NORMAL, gvs->strategy);
if (leftBlkno != InvalidBlockNumber)
lBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, leftBlkno,
RBM_NORMAL, gvs->strategy);
else
lBuffer = InvalidBuffer;
pBuffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, parentBlkno,
RBM_NORMAL, gvs->strategy);
LockBuffer(dBuffer, GIN_EXCLUSIVE);
if (!isParentRoot) /* parent is already locked by
* LockBufferForCleanup() */
LockBuffer(pBuffer, GIN_EXCLUSIVE);
if (leftBlkno != InvalidBlockNumber)
LockBuffer(lBuffer, GIN_EXCLUSIVE);
START_CRIT_SECTION();
if (leftBlkno != InvalidBlockNumber)
{
BlockNumber rightlink;
page = BufferGetPage(dBuffer);
rightlink = GinPageGetOpaque(page)->rightlink;
page = BufferGetPage(lBuffer);
GinPageGetOpaque(page)->rightlink = rightlink;
}
parentPage = BufferGetPage(pBuffer);
#ifdef USE_ASSERT_CHECKING
do
{
PostingItem *tod = (PostingItem *) GinDataPageGetItem(parentPage, myoff);
Assert(PostingItemGetBlockNumber(tod) == deleteBlkno);
} while (0);
#endif
PageDeletePostingItem(parentPage, myoff);
page = BufferGetPage(dBuffer);
/*
* we shouldn't change rightlink field to save workability of running
* search scan
*/
GinPageGetOpaque(page)->flags = GIN_DELETED;
MarkBufferDirty(pBuffer);
if (leftBlkno != InvalidBlockNumber)
MarkBufferDirty(lBuffer);
MarkBufferDirty(dBuffer);
if (!gvs->index->rd_istemp)
{
XLogRecPtr recptr;
XLogRecData rdata[4];
ginxlogDeletePage data;
int n;
data.node = gvs->index->rd_node;
data.blkno = deleteBlkno;
data.parentBlkno = parentBlkno;
data.parentOffset = myoff;
data.leftBlkno = leftBlkno;
data.rightLink = GinPageGetOpaque(page)->rightlink;
rdata[0].buffer = dBuffer;
rdata[0].buffer_std = FALSE;
rdata[0].data = NULL;
rdata[0].len = 0;
rdata[0].next = rdata + 1;
rdata[1].buffer = pBuffer;
rdata[1].buffer_std = FALSE;
rdata[1].data = NULL;
rdata[1].len = 0;
rdata[1].next = rdata + 2;
if (leftBlkno != InvalidBlockNumber)
{
rdata[2].buffer = lBuffer;
rdata[2].buffer_std = FALSE;
rdata[2].data = NULL;
rdata[2].len = 0;
rdata[2].next = rdata + 3;
n = 3;
}
else
n = 2;
rdata[n].buffer = InvalidBuffer;
rdata[n].buffer_std = FALSE;
rdata[n].len = sizeof(ginxlogDeletePage);
rdata[n].data = (char *) &data;
rdata[n].next = NULL;
recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_DELETE_PAGE, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
PageSetLSN(parentPage, recptr);
PageSetTLI(parentPage, ThisTimeLineID);
if (leftBlkno != InvalidBlockNumber)
{
page = BufferGetPage(lBuffer);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
}
if (!isParentRoot)
LockBuffer(pBuffer, GIN_UNLOCK);
ReleaseBuffer(pBuffer);
if (leftBlkno != InvalidBlockNumber)
UnlockReleaseBuffer(lBuffer);
UnlockReleaseBuffer(dBuffer);
END_CRIT_SECTION();
gvs->result->pages_deleted++;
}
/*
* btvacuumscan --- scan the index for VACUUMing purposes
*
* This combines the functions of looking for leaf tuples that are deletable
* according to the vacuum callback, looking for empty pages that can be
* deleted, and looking for old deleted pages that can be recycled. Both
* btbulkdelete and btvacuumcleanup invoke this (the latter only if no
* btbulkdelete call occurred).
*
* The caller is responsible for initially allocating/zeroing a stats struct
* and for obtaining a vacuum cycle ID if necessary.
*/
static void
btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback, void *callback_state,
BTCycleId cycleid)
{
Relation rel = info->index;
BTVacState vstate;
BlockNumber num_pages;
BlockNumber blkno;
bool needLock;
/*
* Reset counts that will be incremented during the scan; needed in case
* of multiple scans during a single VACUUM command
*/
stats->estimated_count = false;
stats->num_index_tuples = 0;
stats->pages_deleted = 0;
/* Set up info to pass down to btvacuumpage */
vstate.info = info;
vstate.stats = stats;
vstate.callback = callback;
vstate.callback_state = callback_state;
vstate.cycleid = cycleid;
vstate.lastBlockVacuumed = BTREE_METAPAGE; /* Initialise at first block */
vstate.lastBlockLocked = BTREE_METAPAGE;
vstate.totFreePages = 0;
/* Create a temporary memory context to run _bt_pagedel in */
vstate.pagedelcontext = AllocSetContextCreate(CurrentMemoryContext,
"_bt_pagedel",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/*
* The outer loop iterates over all index pages except the metapage, in
* physical order (we hope the kernel will cooperate in providing
* read-ahead for speed). It is critical that we visit all leaf pages,
* including ones added after we start the scan, else we might fail to
* delete some deletable tuples. Hence, we must repeatedly check the
* relation length. We must acquire the relation-extension lock while
* doing so to avoid a race condition: if someone else is extending the
* relation, there is a window where bufmgr/smgr have created a new
* all-zero page but it hasn't yet been write-locked by _bt_getbuf(). If
* we manage to scan such a page here, we'll improperly assume it can be
* recycled. Taking the lock synchronizes things enough to prevent a
* problem: either num_pages won't include the new page, or _bt_getbuf
* already has write lock on the buffer and it will be fully initialized
* before we can examine it. (See also vacuumlazy.c, which has the same
* issue.) Also, we need not worry if a page is added immediately after
* we look; the page splitting code already has write-lock on the left
* page before it adds a right page, so we must already have processed any
* tuples due to be moved into such a page.
*
* We can skip locking for new or temp relations, however, since no one
* else could be accessing them.
*/
needLock = !RELATION_IS_LOCAL(rel);
blkno = BTREE_METAPAGE + 1;
for (;;)
{
/* Get the current relation length */
if (needLock)
LockRelationForExtension(rel, ExclusiveLock);
num_pages = RelationGetNumberOfBlocks(rel);
if (needLock)
UnlockRelationForExtension(rel, ExclusiveLock);
/* Quit if we've scanned the whole relation */
if (blkno >= num_pages)
break;
/* Iterate over pages, then loop back to recheck length */
for (; blkno < num_pages; blkno++)
{
btvacuumpage(&vstate, blkno, blkno);
}
}
/*
* If the WAL is replayed in hot standby, the replay process needs to get
* cleanup locks on all index leaf pages, just as we've been doing here.
* However, we won't issue any WAL records about pages that have no items
* to be deleted. For pages between pages we've vacuumed, the replay code
* will take locks under the direction of the lastBlockVacuumed fields in
* the XLOG_BTREE_VACUUM WAL records. To cover pages after the last one
* we vacuum, we need to issue a dummy XLOG_BTREE_VACUUM WAL record
* against the last leaf page in the index, if that one wasn't vacuumed.
*/
if (XLogStandbyInfoActive() &&
vstate.lastBlockVacuumed < vstate.lastBlockLocked)
{
Buffer buf;
/*
* The page should be valid, but we can't use _bt_getbuf() because we
* want to use a nondefault buffer access strategy. Since we aren't
* going to delete any items, getting cleanup lock again is probably
* overkill, but for consistency do that anyway.
*/
buf = ReadBufferExtended(rel, MAIN_FORKNUM, vstate.lastBlockLocked,
RBM_NORMAL, info->strategy);
LockBufferForCleanup(buf);
_bt_checkpage(rel, buf);
_bt_delitems_vacuum(rel, buf, NULL, 0, vstate.lastBlockVacuumed);
_bt_relbuf(rel, buf);
}
MemoryContextDelete(vstate.pagedelcontext);
/* update statistics */
stats->num_pages = num_pages;
stats->pages_free = vstate.totFreePages;
}
Datum
ginbulkdelete(PG_FUNCTION_ARGS)
{
IndexVacuumInfo *info = (IndexVacuumInfo *) PG_GETARG_POINTER(0);
IndexBulkDeleteResult *stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(1);
IndexBulkDeleteCallback callback = (IndexBulkDeleteCallback) PG_GETARG_POINTER(2);
void *callback_state = (void *) PG_GETARG_POINTER(3);
Relation index = info->index;
BlockNumber blkno = GIN_ROOT_BLKNO;
GinVacuumState gvs;
Buffer buffer;
BlockNumber rootOfPostingTree[BLCKSZ / (sizeof(IndexTupleData) + sizeof(ItemId))];
uint32 nRoot;
gvs.index = index;
gvs.callback = callback;
gvs.callback_state = callback_state;
gvs.strategy = info->strategy;
initGinState(&gvs.ginstate, index);
/* first time through? */
if (stats == NULL)
{
/* Yes, so initialize stats to zeroes */
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
/* and cleanup any pending inserts */
ginInsertCleanup(index, &gvs.ginstate, true, stats);
}
/* we'll re-count the tuples each time */
stats->num_index_tuples = 0;
gvs.result = stats;
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
/* find leaf page */
for (;;)
{
Page page = BufferGetPage(buffer);
IndexTuple itup;
LockBuffer(buffer, GIN_SHARE);
Assert(!GinPageIsData(page));
if (GinPageIsLeaf(page))
{
LockBuffer(buffer, GIN_UNLOCK);
LockBuffer(buffer, GIN_EXCLUSIVE);
if (blkno == GIN_ROOT_BLKNO && !GinPageIsLeaf(page))
{
LockBuffer(buffer, GIN_UNLOCK);
continue; /* check it one more */
}
break;
}
Assert(PageGetMaxOffsetNumber(page) >= FirstOffsetNumber);
itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, FirstOffsetNumber));
blkno = GinItemPointerGetBlockNumber(&(itup)->t_tid);
Assert(blkno != InvalidBlockNumber);
UnlockReleaseBuffer(buffer);
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
}
/* right now we found leftmost page in entry's BTree */
for (;;)
{
Page page = BufferGetPage(buffer);
Page resPage;
uint32 i;
Assert(!GinPageIsData(page));
resPage = ginVacuumEntryPage(&gvs, buffer, rootOfPostingTree, &nRoot);
blkno = GinPageGetOpaque(page)->rightlink;
if (resPage)
{
START_CRIT_SECTION();
PageRestoreTempPage(resPage, page);
MarkBufferDirty(buffer);
xlogVacuumPage(gvs.index, buffer);
UnlockReleaseBuffer(buffer);
END_CRIT_SECTION();
}
else
{
UnlockReleaseBuffer(buffer);
}
vacuum_delay_point();
for (i = 0; i < nRoot; i++)
{
ginVacuumPostingTree(&gvs, rootOfPostingTree[i]);
vacuum_delay_point();
}
if (blkno == InvalidBlockNumber) /* rightmost page */
break;
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
LockBuffer(buffer, GIN_EXCLUSIVE);
}
PG_RETURN_POINTER(gvs.result);
}
/*
* Bulk deletion of all index entries pointing to a set of heap tuples.
* The set of target tuples is specified via a callback routine that tells
* whether any given heap tuple (identified by ItemPointer) is being deleted.
*
* Result: a palloc'd struct containing statistical info for VACUUM displays.
*/
IndexBulkDeleteResult *
blbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback, void *callback_state)
{
Relation index = info->index;
BlockNumber blkno,
npages;
FreeBlockNumberArray notFullPage;
int countPage = 0;
BloomState state;
Buffer buffer;
Page page;
GenericXLogState *gxlogState;
if (stats == NULL)
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
initBloomState(&state, index);
/*
* Interate over the pages. We don't care about concurrently added pages,
* they can't contain tuples to delete.
*/
npages = RelationGetNumberOfBlocks(index);
for (blkno = BLOOM_HEAD_BLKNO; blkno < npages; blkno++)
{
BloomTuple *itup,
*itupPtr,
*itupEnd;
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
gxlogState = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(gxlogState, buffer, 0);
if (BloomPageIsDeleted(page))
{
UnlockReleaseBuffer(buffer);
GenericXLogAbort(gxlogState);
CHECK_FOR_INTERRUPTS();
continue;
}
/* Iterate over the tuples */
itup = itupPtr = BloomPageGetTuple(&state, page, FirstOffsetNumber);
itupEnd = BloomPageGetTuple(&state, page,
OffsetNumberNext(BloomPageGetMaxOffset(page)));
while (itup < itupEnd)
{
/* Do we have to delete this tuple? */
if (callback(&itup->heapPtr, callback_state))
{
stats->tuples_removed += 1;
BloomPageGetOpaque(page)->maxoff--;
}
else
{
if (itupPtr != itup)
{
/*
* If we already delete something before, we have to move
* this tuple backward.
*/
memmove((Pointer) itupPtr, (Pointer) itup,
state.sizeOfBloomTuple);
}
stats->num_index_tuples++;
itupPtr = BloomPageGetNextTuple(&state, itupPtr);
}
itup = BloomPageGetNextTuple(&state, itup);
}
Assert(itupPtr == BloomPageGetTuple(&state, page,
OffsetNumberNext(BloomPageGetMaxOffset(page))));
/*
* Add page to notFullPage list if we will not mark page as deleted and
* there is a free space on it
*/
if (BloomPageGetMaxOffset(page) != 0 &&
BloomPageGetFreeSpace(&state, page) > state.sizeOfBloomTuple &&
countPage < BloomMetaBlockN)
notFullPage[countPage++] = blkno;
/* Did we delete something? */
if (itupPtr != itup)
{
/* Is it empty page now? */
if (BloomPageGetMaxOffset(page) == 0)
BloomPageSetDeleted(page);
/* Adjust pg_lower */
((PageHeader) page)->pd_lower = (Pointer) itupPtr - page;
/* Finish WAL-logging */
GenericXLogFinish(gxlogState);
}
else
{
/* Didn't change anything: abort WAL-logging */
GenericXLogAbort(gxlogState);
}
UnlockReleaseBuffer(buffer);
CHECK_FOR_INTERRUPTS();
}
if (countPage > 0)
{
BloomMetaPageData *metaData;
buffer = ReadBuffer(index, BLOOM_METAPAGE_BLKNO);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
gxlogState = GenericXLogStart(index);
page = GenericXLogRegisterBuffer(gxlogState, buffer, 0);
metaData = BloomPageGetMeta(page);
memcpy(metaData->notFullPage, notFullPage, sizeof(BlockNumber) * countPage);
metaData->nStart = 0;
metaData->nEnd = countPage;
GenericXLogFinish(gxlogState);
UnlockReleaseBuffer(buffer);
}
return stats;
}
Datum
ginvacuumcleanup(PG_FUNCTION_ARGS)
{
IndexVacuumInfo *info = (IndexVacuumInfo *) PG_GETARG_POINTER(0);
IndexBulkDeleteResult *stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(1);
Relation index = info->index;
bool needLock;
BlockNumber npages,
blkno;
BlockNumber totFreePages;
BlockNumber lastBlock = GIN_ROOT_BLKNO,
lastFilledBlock = GIN_ROOT_BLKNO;
GinState ginstate;
/*
* In an autovacuum analyze, we want to clean up pending insertions.
* Otherwise, an ANALYZE-only call is a no-op.
*/
if (info->analyze_only)
{
if (IsAutoVacuumWorkerProcess())
{
initGinState(&ginstate, index);
ginInsertCleanup(index, &ginstate, true, stats);
}
PG_RETURN_POINTER(stats);
}
/*
* Set up all-zero stats and cleanup pending inserts if ginbulkdelete
* wasn't called
*/
if (stats == NULL)
{
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
initGinState(&ginstate, index);
ginInsertCleanup(index, &ginstate, true, stats);
}
/*
* XXX we always report the heap tuple count as the number of index
* entries. This is bogus if the index is partial, but it's real hard to
* tell how many distinct heap entries are referenced by a GIN index.
*/
stats->num_index_tuples = info->num_heap_tuples;
stats->estimated_count = info->estimated_count;
/*
* Need lock unless it's local to this backend.
*/
needLock = !RELATION_IS_LOCAL(index);
if (needLock)
LockRelationForExtension(index, ExclusiveLock);
npages = RelationGetNumberOfBlocks(index);
if (needLock)
UnlockRelationForExtension(index, ExclusiveLock);
totFreePages = 0;
for (blkno = GIN_ROOT_BLKNO + 1; blkno < npages; blkno++)
{
Buffer buffer;
Page page;
vacuum_delay_point();
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
LockBuffer(buffer, GIN_SHARE);
page = (Page) BufferGetPage(buffer);
if (GinPageIsDeleted(page))
{
RecordFreeIndexPage(index, blkno);
totFreePages++;
}
else
lastFilledBlock = blkno;
UnlockReleaseBuffer(buffer);
}
lastBlock = npages - 1;
/* Finally, vacuum the FSM */
IndexFreeSpaceMapVacuum(info->index);
stats->pages_free = totFreePages;
if (needLock)
LockRelationForExtension(index, ExclusiveLock);
stats->num_pages = RelationGetNumberOfBlocks(index);
if (needLock)
UnlockRelationForExtension(index, ExclusiveLock);
PG_RETURN_POINTER(stats);
}
/*
* scans posting tree and deletes empty pages
*/
static bool
ginScanToDelete(GinVacuumState *gvs, BlockNumber blkno, bool isRoot,
DataPageDeleteStack *parent, OffsetNumber myoff)
{
DataPageDeleteStack *me;
Buffer buffer;
Page page;
bool meDelete = FALSE;
bool isempty;
if (isRoot)
{
me = parent;
}
else
{
if (!parent->child)
{
me = (DataPageDeleteStack *) palloc0(sizeof(DataPageDeleteStack));
me->parent = parent;
parent->child = me;
me->leftBlkno = InvalidBlockNumber;
}
else
me = parent->child;
}
buffer = ReadBufferExtended(gvs->index, MAIN_FORKNUM, blkno,
RBM_NORMAL, gvs->strategy);
if (!isRoot)
LockBuffer(buffer, GIN_EXCLUSIVE);
page = BufferGetPage(buffer);
Assert(GinPageIsData(page));
if (!GinPageIsLeaf(page))
{
OffsetNumber i;
me->blkno = blkno;
for (i = FirstOffsetNumber; i <= GinPageGetOpaque(page)->maxoff; i++)
{
PostingItem *pitem = GinDataPageGetPostingItem(page, i);
if (ginScanToDelete(gvs, PostingItemGetBlockNumber(pitem), FALSE, me, i))
i--;
}
}
if (GinPageIsLeaf(page))
isempty = GinDataLeafPageIsEmpty(page);
else
isempty = GinPageGetOpaque(page)->maxoff < FirstOffsetNumber;
if (isempty)
{
/* we never delete the left- or rightmost branch */
if (me->leftBlkno != InvalidBlockNumber && !GinPageRightMost(page))
{
Assert(!isRoot);
ginDeletePage(gvs, blkno, me->leftBlkno, me->parent->blkno, myoff, me->parent->isRoot);
meDelete = TRUE;
}
}
if (!isRoot)
LockBuffer(buffer, GIN_UNLOCK);
ReleaseBuffer(buffer);
if (!meDelete)
me->leftBlkno = blkno;
return meDelete;
}
/*
* Process one page during a bulkdelete scan
*/
static void
spgvacuumpage(spgBulkDeleteState *bds, BlockNumber blkno)
{
Relation index = bds->info->index;
Buffer buffer;
Page page;
/* call vacuum_delay_point while not holding any buffer lock */
vacuum_delay_point();
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, bds->info->strategy);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew(page))
{
/*
* We found an all-zero page, which could happen if the database
* crashed just after extending the file. Recycle it.
*/
}
else if (PageIsEmpty(page))
{
/* nothing to do */
}
else if (SpGistPageIsLeaf(page))
{
if (SpGistBlockIsRoot(blkno))
{
vacuumLeafRoot(bds, index, buffer);
/* no need for vacuumRedirectAndPlaceholder */
}
else
{
vacuumLeafPage(bds, index, buffer, false);
vacuumRedirectAndPlaceholder(index, buffer);
}
}
else
{
/* inner page */
vacuumRedirectAndPlaceholder(index, buffer);
}
/*
* The root pages must never be deleted, nor marked as available in FSM,
* because we don't want them ever returned by a search for a place to put
* a new tuple. Otherwise, check for empty page, and make sure the FSM
* knows about it.
*/
if (!SpGistBlockIsRoot(blkno))
{
if (PageIsNew(page) || PageIsEmpty(page))
{
RecordFreeIndexPage(index, blkno);
bds->stats->pages_deleted++;
}
else
{
SpGistSetLastUsedPage(index, buffer);
bds->lastFilledBlock = blkno;
}
}
UnlockReleaseBuffer(buffer);
}
IndexBulkDeleteResult *
ginbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback, void *callback_state)
{
Relation index = info->index;
BlockNumber blkno = GIN_ROOT_BLKNO;
GinVacuumState gvs;
Buffer buffer;
BlockNumber rootOfPostingTree[BLCKSZ / (sizeof(IndexTupleData) + sizeof(ItemId))];
uint32 nRoot;
gvs.tmpCxt = AllocSetContextCreate(CurrentMemoryContext,
"Gin vacuum temporary context",
ALLOCSET_DEFAULT_SIZES);
gvs.index = index;
gvs.callback = callback;
gvs.callback_state = callback_state;
gvs.strategy = info->strategy;
initGinState(&gvs.ginstate, index);
/* first time through? */
if (stats == NULL)
{
/* Yes, so initialize stats to zeroes */
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
/*
* and cleanup any pending inserts
*/
ginInsertCleanup(&gvs.ginstate, !IsAutoVacuumWorkerProcess(),
false, stats);
}
/* we'll re-count the tuples each time */
stats->num_index_tuples = 0;
gvs.result = stats;
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
/* find leaf page */
for (;;)
{
Page page = BufferGetPage(buffer);
IndexTuple itup;
LockBuffer(buffer, GIN_SHARE);
Assert(!GinPageIsData(page));
if (GinPageIsLeaf(page))
{
LockBuffer(buffer, GIN_UNLOCK);
LockBuffer(buffer, GIN_EXCLUSIVE);
if (blkno == GIN_ROOT_BLKNO && !GinPageIsLeaf(page))
{
LockBuffer(buffer, GIN_UNLOCK);
continue; /* check it one more */
}
break;
}
Assert(PageGetMaxOffsetNumber(page) >= FirstOffsetNumber);
itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, FirstOffsetNumber));
blkno = GinGetDownlink(itup);
Assert(blkno != InvalidBlockNumber);
UnlockReleaseBuffer(buffer);
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
}
/* right now we found leftmost page in entry's BTree */
for (;;)
{
Page page = BufferGetPage(buffer);
Page resPage;
uint32 i;
Assert(!GinPageIsData(page));
resPage = ginVacuumEntryPage(&gvs, buffer, rootOfPostingTree, &nRoot);
blkno = GinPageGetOpaque(page)->rightlink;
if (resPage)
{
START_CRIT_SECTION();
PageRestoreTempPage(resPage, page);
MarkBufferDirty(buffer);
xlogVacuumPage(gvs.index, buffer);
UnlockReleaseBuffer(buffer);
END_CRIT_SECTION();
}
else
{
UnlockReleaseBuffer(buffer);
}
vacuum_delay_point();
for (i = 0; i < nRoot; i++)
{
ginVacuumPostingTree(&gvs, rootOfPostingTree[i]);
vacuum_delay_point();
}
if (blkno == InvalidBlockNumber) /* rightmost page */
break;
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, info->strategy);
LockBuffer(buffer, GIN_EXCLUSIVE);
}
MemoryContextDelete(gvs.tmpCxt);
return gvs.result;
}
/*
* Process the pending-TID list between pages of the main scan
*/
static void
spgprocesspending(spgBulkDeleteState *bds)
{
Relation index = bds->info->index;
spgVacPendingItem *pitem;
spgVacPendingItem *nitem;
BlockNumber blkno;
Buffer buffer;
Page page;
for (pitem = bds->pendingList; pitem != NULL; pitem = pitem->next)
{
if (pitem->done)
continue; /* ignore already-done items */
/* call vacuum_delay_point while not holding any buffer lock */
vacuum_delay_point();
/* examine the referenced page */
blkno = ItemPointerGetBlockNumber(&pitem->tid);
buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
RBM_NORMAL, bds->info->strategy);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
page = (Page) BufferGetPage(buffer);
if (PageIsNew(page) || SpGistPageIsDeleted(page))
{
/* Probably shouldn't happen, but ignore it */
}
else if (SpGistPageIsLeaf(page))
{
if (SpGistBlockIsRoot(blkno))
{
/* this should definitely not happen */
elog(ERROR, "redirection leads to root page of index \"%s\"",
RelationGetRelationName(index));
}
/* deal with any deletable tuples */
vacuumLeafPage(bds, index, buffer, true);
/* might as well do this while we are here */
vacuumRedirectAndPlaceholder(index, buffer);
SpGistSetLastUsedPage(index, buffer);
/*
* We can mark as done not only this item, but any later ones
* pointing at the same page, since we vacuumed the whole page.
*/
pitem->done = true;
for (nitem = pitem->next; nitem != NULL; nitem = nitem->next)
{
if (ItemPointerGetBlockNumber(&nitem->tid) == blkno)
nitem->done = true;
}
}
else
{
/*
* On an inner page, visit the referenced inner tuple and add all
* its downlinks to the pending list. We might have pending items
* for more than one inner tuple on the same page (in fact this is
* pretty likely given the way space allocation works), so get
* them all while we are here.
*/
for (nitem = pitem; nitem != NULL; nitem = nitem->next)
{
if (nitem->done)
continue;
if (ItemPointerGetBlockNumber(&nitem->tid) == blkno)
{
OffsetNumber offset;
SpGistInnerTuple innerTuple;
offset = ItemPointerGetOffsetNumber(&nitem->tid);
innerTuple = (SpGistInnerTuple) PageGetItem(page,
PageGetItemId(page, offset));
if (innerTuple->tupstate == SPGIST_LIVE)
{
SpGistNodeTuple node;
int i;
SGITITERATE(innerTuple, i, node)
{
if (ItemPointerIsValid(&node->t_tid))
spgAddPendingTID(bds, &node->t_tid);
}
}
else if (innerTuple->tupstate == SPGIST_REDIRECT)
{
/* transfer attention to redirect point */
spgAddPendingTID(bds,
&((SpGistDeadTuple) innerTuple)->pointer);
}
else
elog(ERROR, "unexpected SPGiST tuple state: %d",
innerTuple->tupstate);
nitem->done = true;
}
}
/*
* Rescan end pages to verify that they are (still) empty of tuples.
*
* Returns number of nondeletable pages (last nonempty page + 1).
*/
static BlockNumber
count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats)
{
BlockNumber blkno;
/* Strange coding of loop control is needed because blkno is unsigned */
blkno = vacrelstats->rel_pages;
while (blkno > vacrelstats->nonempty_pages)
{
Buffer buf;
Page page;
OffsetNumber offnum,
maxoff;
bool hastup;
/*
* We don't insert a vacuum delay point here, because we have an
* exclusive lock on the table which we want to hold for as short a
* time as possible. We still need to check for interrupts however.
*/
CHECK_FOR_INTERRUPTS();
blkno--;
buf = ReadBufferExtended(onerel, MAIN_FORKNUM, blkno,
RBM_NORMAL, vac_strategy);
/* In this phase we only need shared access to the buffer */
LockBuffer(buf, BUFFER_LOCK_SHARE);
page = BufferGetPage(buf);
if (PageIsNew(page) || PageIsEmpty(page))
{
/* PageIsNew probably shouldn't happen... */
UnlockReleaseBuffer(buf);
continue;
}
hastup = false;
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
ItemId itemid;
itemid = PageGetItemId(page, offnum);
/*
* Note: any non-unused item should be taken as a reason to keep
* this page. We formerly thought that DEAD tuples could be
* thrown away, but that's not so, because we'd not have cleaned
* out their index entries.
*/
if (ItemIdIsUsed(itemid))
{
hastup = true;
break; /* can stop scanning */
}
} /* scan along page */
UnlockReleaseBuffer(buf);
/* Done scanning if we found a tuple here */
if (hastup)
return blkno + 1;
}
/*
* If we fall out of the loop, all the previously-thought-to-be-empty
* pages still are; we need not bother to look at the last known-nonempty
* page.
*/
return vacrelstats->nonempty_pages;
}
/*
* Bulk deletion of all index entries pointing to a set of heap tuples.
* The set of target tuples is specified via a callback routine that tells
* whether any given heap tuple (identified by ItemPointer) is being deleted.
*
* This function also deletes the tuples that are moved by split to other
* bucket.
*
* Result: a palloc'd struct containing statistical info for VACUUM displays.
*/
IndexBulkDeleteResult *
hashbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback, void *callback_state)
{
Relation rel = info->index;
double tuples_removed;
double num_index_tuples;
double orig_ntuples;
Bucket orig_maxbucket;
Bucket cur_maxbucket;
Bucket cur_bucket;
Buffer metabuf;
HashMetaPage metap;
HashMetaPageData local_metapage;
tuples_removed = 0;
num_index_tuples = 0;
/*
* Read the metapage to fetch original bucket and tuple counts. Also, we
* keep a copy of the last-seen metapage so that we can use its
* hashm_spares[] values to compute bucket page addresses. This is a bit
* hokey but perfectly safe, since the interesting entries in the spares
* array cannot change under us; and it beats rereading the metapage for
* each bucket.
*/
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ, LH_META_PAGE);
metap = HashPageGetMeta(BufferGetPage(metabuf));
orig_maxbucket = metap->hashm_maxbucket;
orig_ntuples = metap->hashm_ntuples;
memcpy(&local_metapage, metap, sizeof(local_metapage));
/* release the lock, but keep pin */
LockBuffer(metabuf, BUFFER_LOCK_UNLOCK);
/* Scan the buckets that we know exist */
cur_bucket = 0;
cur_maxbucket = orig_maxbucket;
loop_top:
while (cur_bucket <= cur_maxbucket)
{
BlockNumber bucket_blkno;
BlockNumber blkno;
Buffer bucket_buf;
Buffer buf;
HashPageOpaque bucket_opaque;
Page page;
bool split_cleanup = false;
/* Get address of bucket's start page */
bucket_blkno = BUCKET_TO_BLKNO(&local_metapage, cur_bucket);
blkno = bucket_blkno;
/*
* We need to acquire a cleanup lock on the primary bucket page to out
* wait concurrent scans before deleting the dead tuples.
*/
buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, info->strategy);
LockBufferForCleanup(buf);
_hash_checkpage(rel, buf, LH_BUCKET_PAGE);
page = BufferGetPage(buf);
bucket_opaque = (HashPageOpaque) PageGetSpecialPointer(page);
/*
* If the bucket contains tuples that are moved by split, then we need
* to delete such tuples. We can't delete such tuples if the split
* operation on bucket is not finished as those are needed by scans.
*/
if (!H_BUCKET_BEING_SPLIT(bucket_opaque) &&
H_NEEDS_SPLIT_CLEANUP(bucket_opaque))
{
split_cleanup = true;
/*
* This bucket might have been split since we last held a lock on
* the metapage. If so, hashm_maxbucket, hashm_highmask and
* hashm_lowmask might be old enough to cause us to fail to remove
* tuples left behind by the most recent split. To prevent that,
* now that the primary page of the target bucket has been locked
* (and thus can't be further split), update our cached metapage
* data.
*/
LockBuffer(metabuf, BUFFER_LOCK_SHARE);
memcpy(&local_metapage, metap, sizeof(local_metapage));
LockBuffer(metabuf, BUFFER_LOCK_UNLOCK);
}
bucket_buf = buf;
hashbucketcleanup(rel, cur_bucket, bucket_buf, blkno, info->strategy,
local_metapage.hashm_maxbucket,
local_metapage.hashm_highmask,
local_metapage.hashm_lowmask, &tuples_removed,
&num_index_tuples, split_cleanup,
callback, callback_state);
_hash_dropbuf(rel, bucket_buf);
/* Advance to next bucket */
cur_bucket++;
}
/* Write-lock metapage and check for split since we started */
LockBuffer(metabuf, BUFFER_LOCK_EXCLUSIVE);
metap = HashPageGetMeta(BufferGetPage(metabuf));
if (cur_maxbucket != metap->hashm_maxbucket)
{
/* There's been a split, so process the additional bucket(s) */
cur_maxbucket = metap->hashm_maxbucket;
memcpy(&local_metapage, metap, sizeof(local_metapage));
LockBuffer(metabuf, BUFFER_LOCK_UNLOCK);
goto loop_top;
}
/* Okay, we're really done. Update tuple count in metapage. */
if (orig_maxbucket == metap->hashm_maxbucket &&
orig_ntuples == metap->hashm_ntuples)
{
/*
* No one has split or inserted anything since start of scan, so
* believe our count as gospel.
*/
metap->hashm_ntuples = num_index_tuples;
}
else
{
/*
* Otherwise, our count is untrustworthy since we may have
* double-scanned tuples in split buckets. Proceed by dead-reckoning.
* (Note: we still return estimated_count = false, because using this
* count is better than not updating reltuples at all.)
*/
if (metap->hashm_ntuples > tuples_removed)
metap->hashm_ntuples -= tuples_removed;
else
metap->hashm_ntuples = 0;
num_index_tuples = metap->hashm_ntuples;
}
MarkBufferDirty(metabuf);
_hash_relbuf(rel, metabuf);
/* return statistics */
if (stats == NULL)
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
stats->estimated_count = false;
stats->num_index_tuples = num_index_tuples;
stats->tuples_removed += tuples_removed;
/* hashvacuumcleanup will fill in num_pages */
return stats;
}
