Exemple #1
0
/*
 * Allocate a new page (either by recycling, or by extending the index file).
 *
 * The returned buffer is already pinned and exclusive-locked.
 * Caller is responsible for initializing the page by calling SpGistInitBuffer.
 */
Buffer
SpGistNewBuffer(Relation index)
{
	Buffer		buffer;
	bool		needLock;

	/* First, try to get a page from FSM */
	for (;;)
	{
		BlockNumber blkno = GetFreeIndexPage(index);

		if (blkno == InvalidBlockNumber)
			break;				/* nothing known to FSM */

		/*
		 * The fixed pages shouldn't ever be listed in FSM, but just in case
		 * one is, ignore it.
		 */
		if (SpGistBlockIsFixed(blkno))
			continue;

		buffer = ReadBuffer(index, blkno);

		/*
		 * We have to guard against the possibility that someone else already
		 * recycled this page; the buffer may be locked if so.
		 */
		if (ConditionalLockBuffer(buffer))
		{
			Page		page = BufferGetPage(buffer);

			if (PageIsNew(page))
				return buffer;	/* OK to use, if never initialized */

			if (SpGistPageIsDeleted(page) || PageIsEmpty(page))
				return buffer;	/* OK to use */

			LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
		}

		/* Can't use it, so release buffer and try again */
		ReleaseBuffer(buffer);
	}

	/* Must extend the file */
	needLock = !RELATION_IS_LOCAL(index);
	if (needLock)
		LockRelationForExtension(index, ExclusiveLock);

	buffer = ReadBuffer(index, P_NEW);
	LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);

	if (needLock)
		UnlockRelationForExtension(index, ExclusiveLock);

	return buffer;
}
Exemple #2
0
void
_rtdump(Relation r)
{
	Buffer		buf;
	Page		page;
	OffsetNumber offnum,
				maxoff;
	BlockNumber blkno;
	BlockNumber nblocks;
	RTreePageOpaque po;
	IndexTuple	itup;
	BlockNumber itblkno;
	OffsetNumber itoffno;
	Datum		datum;
	char	   *itkey;

	nblocks = RelationGetNumberOfBlocks(r);
	for (blkno = 0; blkno < nblocks; blkno++)
	{
		buf = ReadBuffer(r, blkno);
		page = BufferGetPage(buf);
		po = (RTreePageOpaque) PageGetSpecialPointer(page);
		maxoff = PageGetMaxOffsetNumber(page);
		printf("Page %d maxoff %d <%s>\n", blkno, maxoff,
			   (po->flags & F_LEAF ? "LEAF" : "INTERNAL"));

		if (PageIsEmpty(page))
		{
			ReleaseBuffer(buf);
			continue;
		}

		for (offnum = FirstOffsetNumber;
			 offnum <= maxoff;
			 offnum = OffsetNumberNext(offnum))
		{
			itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, offnum));
			itblkno = ItemPointerGetBlockNumber(&(itup->t_tid));
			itoffno = ItemPointerGetOffsetNumber(&(itup->t_tid));
			datum = IndexTupleGetDatum(itup);
			itkey = DatumGetCString(DirectFunctionCall1(box_out,
														datum));
			printf("\t[%d] size %d heap <%d,%d> key:%s\n",
				   offnum, IndexTupleSize(itup), itblkno, itoffno, itkey);
			pfree(itkey);
		}

		ReleaseBuffer(buf);
	}
}
Exemple #3
0
/*
 * slide an array of ItemIds back one slot (from P_FIRSTKEY to
 * P_HIKEY, overwriting P_HIKEY).  we need to do this when we discover
 * that we have built an ItemId array in what has turned out to be a
 * P_RIGHTMOST page.
 */
static void
_bt_slideleft(Page page)
{
	OffsetNumber off;
	OffsetNumber maxoff;
	ItemId		previi;
	ItemId		thisii;

	if (!PageIsEmpty(page))
	{
		maxoff = PageGetMaxOffsetNumber(page);
		previi = PageGetItemId(page, P_HIKEY);
		for (off = P_FIRSTKEY; off <= maxoff; off = OffsetNumberNext(off))
		{
			thisii = PageGetItemId(page, off);
			*previi = *thisii;
			previi = thisii;
		}
		((PageHeader) page)->pd_lower -= sizeof(ItemIdData);
	}
}
Exemple #4
0
/*
 * Write itup vector to page, has no control of free space.
 */
void
gistfillbuffer(Page page, IndexTuple *itup, int len, OffsetNumber off)
{
	OffsetNumber l = InvalidOffsetNumber;
	int			i;

	if (off == InvalidOffsetNumber)
		off = (PageIsEmpty(page)) ? FirstOffsetNumber :
			OffsetNumberNext(PageGetMaxOffsetNumber(page));

	for (i = 0; i < len; i++)
	{
		Size		sz = IndexTupleSize(itup[i]);

		l = PageAddItem(page, (Item) itup[i], sz, off, false, false);
		if (l == InvalidOffsetNumber)
			elog(ERROR, "failed to add item to GiST index page, item %d out of %d, size %d bytes",
				 i, len, (int) sz);
		off++;
	}
}
/*
 * Write itup vector to page, has no control of free space
 */
OffsetNumber
gistfillbuffer(Relation r, Page page, IndexTuple *itup,
			   int len, OffsetNumber off)
{
	OffsetNumber l = InvalidOffsetNumber;
	int			i;

	if (off == InvalidOffsetNumber)
		off = (PageIsEmpty(page)) ? FirstOffsetNumber :
			OffsetNumberNext(PageGetMaxOffsetNumber(page));

	for (i = 0; i < len; i++)
	{
		l = PageAddItem(page, (Item) itup[i], IndexTupleSize(itup[i]),
						off, LP_USED);
		if (l == InvalidOffsetNumber)
			elog(ERROR, "failed to add item to index page in \"%s\"",
				 RelationGetRelationName(r));
		off++;
	}
	return l;
}
Exemple #6
0
/*
 *	lazy_check_needs_freeze() -- scan page to see if any tuples
 *					 need to be cleaned to avoid wraparound
 *
 * Returns true if the page needs to be vacuumed using cleanup lock.
 */
static bool
lazy_check_needs_freeze(Buffer buf)
{
	Page		page;
	OffsetNumber offnum,
				maxoff;
	HeapTupleHeader tupleheader;

	page = BufferGetPage(buf);

	if (PageIsNew(page) || PageIsEmpty(page))
	{
		/* PageIsNew probably shouldn't happen... */
		return false;
	}

	maxoff = PageGetMaxOffsetNumber(page);
	for (offnum = FirstOffsetNumber;
		 offnum <= maxoff;
		 offnum = OffsetNumberNext(offnum))
	{
		ItemId		itemid;

		itemid = PageGetItemId(page, offnum);

		if (!ItemIdIsNormal(itemid))
			continue;

		tupleheader = (HeapTupleHeader) PageGetItem(page, itemid);

		if (heap_tuple_needs_freeze(tupleheader, FreezeLimit, buf))
			return true;
	}						/* scan along page */

	return false;
}
Exemple #7
0
/*
 *	_bt_step() -- Step one item in the requested direction in a scan on
 *				  the tree.
 *
 *		*bufP is the current buffer (read-locked and pinned).  If we change
 *		pages, it's updated appropriately.
 *
 *		If successful, update scan's currentItemData and return true.
 *		If no adjacent record exists in the requested direction,
 *		release buffer pin/locks and return false.
 */
bool
_bt_step(IndexScanDesc scan, Buffer *bufP, ScanDirection dir)
{
	Relation	rel = scan->indexRelation;
	ItemPointer current = &(scan->currentItemData);
	BTScanOpaque so = (BTScanOpaque) scan->opaque;
	Page		page;
	BTPageOpaque opaque;
	OffsetNumber offnum,
				maxoff;
	BlockNumber blkno;

	/*
	 * Don't use ItemPointerGetOffsetNumber or you risk to get assertion
	 * due to ability of ip_posid to be equal 0.
	 */
	offnum = current->ip_posid;

	page = BufferGetPage(*bufP);
	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
	maxoff = PageGetMaxOffsetNumber(page);

	if (ScanDirectionIsForward(dir))
	{
		if (!PageIsEmpty(page) && offnum < maxoff)
			offnum = OffsetNumberNext(offnum);
		else
		{
			/* Walk right to the next page with data */
			for (;;)
			{
				/* if we're at end of scan, release the buffer and return */
				if (P_RIGHTMOST(opaque))
				{
					_bt_relbuf(rel, *bufP);
					ItemPointerSetInvalid(current);
					*bufP = so->btso_curbuf = InvalidBuffer;
					return false;
				}
				/* step right one page */
				blkno = opaque->btpo_next;
				_bt_relbuf(rel, *bufP);
				*bufP = _bt_getbuf(rel, blkno, BT_READ);
				page = BufferGetPage(*bufP);
				opaque = (BTPageOpaque) PageGetSpecialPointer(page);
				if (!P_IGNORE(opaque))
				{
					maxoff = PageGetMaxOffsetNumber(page);
					/* done if it's not empty */
					offnum = P_FIRSTDATAKEY(opaque);
					if (!PageIsEmpty(page) && offnum <= maxoff)
						break;
				}
			}
		}
	}
	else
/* backwards scan */
	{
		if (offnum > P_FIRSTDATAKEY(opaque))
			offnum = OffsetNumberPrev(offnum);
		else
		{
			/*
			 * Walk left to the next page with data.  This is much more
			 * complex than the walk-right case because of the possibility
			 * that the page to our left splits while we are in flight to
			 * it, plus the possibility that the page we were on gets
			 * deleted after we leave it.  See nbtree/README for details.
			 */
			for (;;)
			{
				*bufP = _bt_walk_left(rel, *bufP);

				/* if we're at end of scan, return failure */
				if (*bufP == InvalidBuffer)
				{
					ItemPointerSetInvalid(current);
					so->btso_curbuf = InvalidBuffer;
					return false;
				}
				page = BufferGetPage(*bufP);
				opaque = (BTPageOpaque) PageGetSpecialPointer(page);

				/*
				 * Okay, we managed to move left to a non-deleted page.
				 * Done if it's not half-dead and not empty.  Else loop
				 * back and do it all again.
				 */
				if (!P_IGNORE(opaque))
				{
					maxoff = PageGetMaxOffsetNumber(page);
					offnum = maxoff;
					if (!PageIsEmpty(page) &&
						maxoff >= P_FIRSTDATAKEY(opaque))
						break;
				}
			}
		}
	}

	/* Update scan state */
	so->btso_curbuf = *bufP;
	blkno = BufferGetBlockNumber(*bufP);
	ItemPointerSet(current, blkno, offnum);

	return true;
}
Exemple #8
0
static void
ginRedoUpdateMetapage(XLogReaderState *record)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	ginxlogUpdateMeta *data = (ginxlogUpdateMeta *) XLogRecGetData(record);
	Buffer		metabuffer;
	Page		metapage;
	Buffer		buffer;

	/*
	 * Restore the metapage. This is essentially the same as a full-page
	 * image, so restore the metapage unconditionally without looking at the
	 * LSN, to avoid torn page hazards.
	 */
	metabuffer = XLogInitBufferForRedo(record, 0);
	Assert(BufferGetBlockNumber(metabuffer) == GIN_METAPAGE_BLKNO);
	metapage = BufferGetPage(metabuffer);

	memcpy(GinPageGetMeta(metapage), &data->metadata, sizeof(GinMetaPageData));
	PageSetLSN(metapage, lsn);
	MarkBufferDirty(metabuffer);

	if (data->ntuples > 0)
	{
		/*
		 * insert into tail page
		 */
		if (XLogReadBufferForRedo(record, 1, &buffer) == BLK_NEEDS_REDO)
		{
			Page		page = BufferGetPage(buffer);
			OffsetNumber off;
			int			i;
			Size		tupsize;
			char	   *payload;
			IndexTuple	tuples;
			Size		totaltupsize;

			payload = XLogRecGetBlockData(record, 1, &totaltupsize);
			tuples = (IndexTuple) payload;

			if (PageIsEmpty(page))
				off = FirstOffsetNumber;
			else
				off = OffsetNumberNext(PageGetMaxOffsetNumber(page));

			for (i = 0; i < data->ntuples; i++)
			{
				tupsize = IndexTupleSize(tuples);

				if (PageAddItem(page, (Item) tuples, tupsize, off,
								false, false) == InvalidOffsetNumber)
					elog(ERROR, "failed to add item to index page");

				tuples = (IndexTuple) (((char *) tuples) + tupsize);

				off++;
			}
			Assert(payload + totaltupsize == (char *) tuples);

			/*
			 * Increase counter of heap tuples
			 */
			GinPageGetOpaque(page)->maxoff++;

			PageSetLSN(page, lsn);
			MarkBufferDirty(buffer);
		}
		if (BufferIsValid(buffer))
			UnlockReleaseBuffer(buffer);
	}
	else if (data->prevTail != InvalidBlockNumber)
	{
		/*
		 * New tail
		 */
		if (XLogReadBufferForRedo(record, 1, &buffer) == BLK_NEEDS_REDO)
		{
			Page		page = BufferGetPage(buffer);

			GinPageGetOpaque(page)->rightlink = data->newRightlink;

			PageSetLSN(page, lsn);
			MarkBufferDirty(buffer);
		}
		if (BufferIsValid(buffer))
			UnlockReleaseBuffer(buffer);
	}

	UnlockReleaseBuffer(metabuffer);
}
/*
 * 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, PROCARRAY_FLAGS_VACUUM);
	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 (VM_ALL_VISIBLE(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;
	}
}
Exemple #10
0
static void
ginRedoUpdateMetapage(XLogRecPtr lsn, XLogRecord *record)
{
    ginxlogUpdateMeta *data = (ginxlogUpdateMeta *) XLogRecGetData(record);
    Buffer		metabuffer;
    Page		metapage;
    Buffer		buffer;

    /*
     * Restore the metapage. This is essentially the same as a full-page
     * image, so restore the metapage unconditionally without looking at the
     * LSN, to avoid torn page hazards.
     */
    metabuffer = XLogReadBuffer(data->node, GIN_METAPAGE_BLKNO, false);
    if (!BufferIsValid(metabuffer))
        return;					/* assume index was deleted, nothing to do */
    metapage = BufferGetPage(metabuffer);

    memcpy(GinPageGetMeta(metapage), &data->metadata, sizeof(GinMetaPageData));
    PageSetLSN(metapage, lsn);
    MarkBufferDirty(metabuffer);

    if (data->ntuples > 0)
    {
        /*
         * insert into tail page
         */
        if (record->xl_info & XLR_BKP_BLOCK(0))
            (void) RestoreBackupBlock(lsn, record, 0, false, false);
        else
        {
            buffer = XLogReadBuffer(data->node, data->metadata.tail, false);
            if (BufferIsValid(buffer))
            {
                Page		page = BufferGetPage(buffer);

                if (lsn > PageGetLSN(page))
                {
                    OffsetNumber l,
                                 off = (PageIsEmpty(page)) ? FirstOffsetNumber :
                                       OffsetNumberNext(PageGetMaxOffsetNumber(page));
                    int			i,
                                tupsize;
                    IndexTuple	tuples = (IndexTuple) (XLogRecGetData(record) + sizeof(ginxlogUpdateMeta));

                    for (i = 0; i < data->ntuples; i++)
                    {
                        tupsize = IndexTupleSize(tuples);

                        l = PageAddItem(page, (Item) tuples, tupsize, off, false, false);

                        if (l == InvalidOffsetNumber)
                            elog(ERROR, "failed to add item to index page");

                        tuples = (IndexTuple) (((char *) tuples) + tupsize);

                        off++;
                    }

                    /*
                     * Increase counter of heap tuples
                     */
                    GinPageGetOpaque(page)->maxoff++;

                    PageSetLSN(page, lsn);
                    MarkBufferDirty(buffer);
                }
                UnlockReleaseBuffer(buffer);
            }
        }
    }
    else if (data->prevTail != InvalidBlockNumber)
    {
        /*
         * New tail
         */
        if (record->xl_info & XLR_BKP_BLOCK(0))
            (void) RestoreBackupBlock(lsn, record, 0, false, false);
        else
        {
            buffer = XLogReadBuffer(data->node, data->prevTail, false);
            if (BufferIsValid(buffer))
            {
                Page		page = BufferGetPage(buffer);

                if (lsn > PageGetLSN(page))
                {
                    GinPageGetOpaque(page)->rightlink = data->newRightlink;

                    PageSetLSN(page, lsn);
                    MarkBufferDirty(buffer);
                }
                UnlockReleaseBuffer(buffer);
            }
        }
    }

    UnlockReleaseBuffer(metabuffer);
}
Exemple #11
0
/*
 * Write the index tuples contained in *collector into the index's
 * pending list.
 *
 * Function guarantees that all these tuples will be inserted consecutively,
 * preserving order
 */
void
ginHeapTupleFastInsert(GinState *ginstate, GinTupleCollector *collector)
{
	Relation	index = ginstate->index;
	Buffer		metabuffer;
	Page		metapage;
	GinMetaPageData *metadata = NULL;
	XLogRecData rdata[2];
	Buffer		buffer = InvalidBuffer;
	Page		page = NULL;
	ginxlogUpdateMeta data;
	bool		separateList = false;
	bool		needCleanup = false;

	if (collector->ntuples == 0)
		return;

	data.node = index->rd_node;
	data.ntuples = 0;
	data.newRightlink = data.prevTail = InvalidBlockNumber;

	rdata[0].buffer = InvalidBuffer;
	rdata[0].data = (char *) &data;
	rdata[0].len = sizeof(ginxlogUpdateMeta);
	rdata[0].next = NULL;

	metabuffer = ReadBuffer(index, GIN_METAPAGE_BLKNO);
	metapage = BufferGetPage(metabuffer);

	if (collector->sumsize + collector->ntuples * sizeof(ItemIdData) > GinListPageSize)
	{
		/*
		 * Total size is greater than one page => make sublist
		 */
		separateList = true;
	}
	else
	{
		LockBuffer(metabuffer, GIN_EXCLUSIVE);
		metadata = GinPageGetMeta(metapage);

		if (metadata->head == InvalidBlockNumber ||
			collector->sumsize + collector->ntuples * sizeof(ItemIdData) > metadata->tailFreeSize)
		{
			/*
			 * Pending list is empty or total size is greater than freespace
			 * on tail page => make sublist
			 *
			 * We unlock metabuffer to keep high concurrency
			 */
			separateList = true;
			LockBuffer(metabuffer, GIN_UNLOCK);
		}
	}

	if (separateList)
	{
		/*
		 * We should make sublist separately and append it to the tail
		 */
		GinMetaPageData sublist;

		memset(&sublist, 0, sizeof(GinMetaPageData));
		makeSublist(index, collector->tuples, collector->ntuples, &sublist);

		/*
		 * metapage was unlocked, see above
		 */
		LockBuffer(metabuffer, GIN_EXCLUSIVE);
		metadata = GinPageGetMeta(metapage);

		if (metadata->head == InvalidBlockNumber)
		{
			/*
			 * Main list is empty, so just insert sublist as main list
			 */
			START_CRIT_SECTION();

			metadata->head = sublist.head;
			metadata->tail = sublist.tail;
			metadata->tailFreeSize = sublist.tailFreeSize;

			metadata->nPendingPages = sublist.nPendingPages;
			metadata->nPendingHeapTuples = sublist.nPendingHeapTuples;
		}
		else
		{
			/*
			 * Merge lists
			 */
			data.prevTail = metadata->tail;
			data.newRightlink = sublist.head;

			buffer = ReadBuffer(index, metadata->tail);
			LockBuffer(buffer, GIN_EXCLUSIVE);
			page = BufferGetPage(buffer);

			rdata[0].next = rdata + 1;

			rdata[1].buffer = buffer;
			rdata[1].buffer_std = true;
			rdata[1].data = NULL;
			rdata[1].len = 0;
			rdata[1].next = NULL;

			Assert(GinPageGetOpaque(page)->rightlink == InvalidBlockNumber);

			START_CRIT_SECTION();

			GinPageGetOpaque(page)->rightlink = sublist.head;

			MarkBufferDirty(buffer);

			metadata->tail = sublist.tail;
			metadata->tailFreeSize = sublist.tailFreeSize;

			metadata->nPendingPages += sublist.nPendingPages;
			metadata->nPendingHeapTuples += sublist.nPendingHeapTuples;
		}
	}
	else
	{
		/*
		 * Insert into tail page.  Metapage is already locked
		 */
		OffsetNumber l,
					off;
		int			i,
					tupsize;
		char	   *ptr;

		buffer = ReadBuffer(index, metadata->tail);
		LockBuffer(buffer, GIN_EXCLUSIVE);
		page = BufferGetPage(buffer);

		off = (PageIsEmpty(page)) ? FirstOffsetNumber :
			OffsetNumberNext(PageGetMaxOffsetNumber(page));

		rdata[0].next = rdata + 1;

		rdata[1].buffer = buffer;
		rdata[1].buffer_std = true;
		ptr = rdata[1].data = (char *) palloc(collector->sumsize);
		rdata[1].len = collector->sumsize;
		rdata[1].next = NULL;

		data.ntuples = collector->ntuples;

		START_CRIT_SECTION();

		/*
		 * Increase counter of heap tuples
		 */
		Assert(GinPageGetOpaque(page)->maxoff <= metadata->nPendingHeapTuples);
		GinPageGetOpaque(page)->maxoff++;
		metadata->nPendingHeapTuples++;

		for (i = 0; i < collector->ntuples; i++)
		{
			tupsize = IndexTupleSize(collector->tuples[i]);
			l = PageAddItem(page, (Item) collector->tuples[i], tupsize, off, false, false);

			if (l == InvalidOffsetNumber)
				elog(ERROR, "failed to add item to index page in \"%s\"",
					 RelationGetRelationName(index));

			memcpy(ptr, collector->tuples[i], tupsize);
			ptr += tupsize;

			off++;
		}

		Assert((ptr - rdata[1].data) <= collector->sumsize);

		metadata->tailFreeSize = PageGetExactFreeSpace(page);

		MarkBufferDirty(buffer);
	}

	/*
	 * Write metabuffer, make xlog entry
	 */
	MarkBufferDirty(metabuffer);

	if (RelationNeedsWAL(index))
	{
		XLogRecPtr	recptr;

		memcpy(&data.metadata, metadata, sizeof(GinMetaPageData));

		recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_UPDATE_META_PAGE, rdata);
		PageSetLSN(metapage, recptr);
		PageSetTLI(metapage, ThisTimeLineID);

		if (buffer != InvalidBuffer)
		{
			PageSetLSN(page, recptr);
			PageSetTLI(page, ThisTimeLineID);
		}
	}

	if (buffer != InvalidBuffer)
		UnlockReleaseBuffer(buffer);

	/*
	 * Force pending list cleanup when it becomes too long. And,
	 * ginInsertCleanup could take significant amount of time, so we prefer to
	 * call it when it can do all the work in a single collection cycle. In
	 * non-vacuum mode, it shouldn't require maintenance_work_mem, so fire it
	 * while pending list is still small enough to fit into work_mem.
	 *
	 * ginInsertCleanup() should not be called inside our CRIT_SECTION.
	 */
	if (metadata->nPendingPages * GIN_PAGE_FREESIZE > work_mem * 1024L)
		needCleanup = true;

	UnlockReleaseBuffer(metabuffer);

	END_CRIT_SECTION();

	if (needCleanup)
		ginInsertCleanup(ginstate, false, NULL);
}
/*
 * redo any page update (except page split)
 */
static void
gistRedoPageUpdateRecord(XLogReaderState *record)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	gistxlogPageUpdate *xldata = (gistxlogPageUpdate *) XLogRecGetData(record);
	Buffer		buffer;
	Page		page;

	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
	{
		char	   *begin;
		char	   *data;
		Size		datalen;
		int			ninserted = 0;

		data = begin = XLogRecGetBlockData(record, 0, &datalen);

		page = (Page) BufferGetPage(buffer);

		/* Delete old tuples */
		if (xldata->ntodelete > 0)
		{
			int			i;
			OffsetNumber *todelete = (OffsetNumber *) data;

			data += sizeof(OffsetNumber) * xldata->ntodelete;

			for (i = 0; i < xldata->ntodelete; i++)
				PageIndexTupleDelete(page, todelete[i]);
			if (GistPageIsLeaf(page))
				GistMarkTuplesDeleted(page);
		}

		/* add tuples */
		if (data - begin < datalen)
		{
			OffsetNumber off = (PageIsEmpty(page)) ? FirstOffsetNumber :
			OffsetNumberNext(PageGetMaxOffsetNumber(page));

			while (data - begin < datalen)
			{
				IndexTuple	itup = (IndexTuple) data;
				Size		sz = IndexTupleSize(itup);
				OffsetNumber l;

				data += sz;

				l = PageAddItem(page, (Item) itup, sz, off, false, false);
				if (l == InvalidOffsetNumber)
					elog(ERROR, "failed to add item to GiST index page, size %d bytes",
						 (int) sz);
				off++;
				ninserted++;
			}
		}

		Assert(ninserted == xldata->ntoinsert);

		PageSetLSN(page, lsn);
		MarkBufferDirty(buffer);
	}

	/*
	 * Fix follow-right data on left child page
	 *
	 * This must be done while still holding the lock on the target page. Note
	 * that even if the target page no longer exists, we still attempt to
	 * replay the change on the child page.
	 */
	if (XLogRecHasBlockRef(record, 1))
		gistRedoClearFollowRight(record, 1);

	if (BufferIsValid(buffer))
		UnlockReleaseBuffer(buffer);
}
/*
 * 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.  Initialize and recycle it.
		 */
		SpGistInitBuffer(buffer, 0);
		SpGistPageSetDeleted(page);
		/* We don't bother to WAL-log this action; easy to redo */
		MarkBufferDirty(buffer);
	}
	else if (SpGistPageIsDeleted(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/deletable page, and make sure
	 * FSM knows about it.
	 */
	if (!SpGistBlockIsRoot(blkno))
	{
		/* If page is now empty, mark it deleted */
		if (PageIsEmpty(page) && !SpGistPageIsDeleted(page))
		{
			SpGistPageSetDeleted(page);
			/* We don't bother to WAL-log this action; easy to redo */
			MarkBufferDirty(buffer);
		}

		if (SpGistPageIsDeleted(page))
		{
			RecordFreeIndexPage(index, blkno);
			bds->stats->pages_deleted++;
		}
		else
			bds->lastFilledBlock = blkno;
	}

	SpGistSetLastUsedPage(index, buffer);

	UnlockReleaseBuffer(buffer);
}
Exemple #14
0
/*
 * redo any page update (except page split)
 */
static void
gistRedoPageUpdateRecord(XLogReaderState *record)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	gistxlogPageUpdate *xldata = (gistxlogPageUpdate *) XLogRecGetData(record);
	Buffer		buffer;
	Page		page;

	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
	{
		char	   *begin;
		char	   *data;
		Size		datalen;
		int			ninserted = 0;

		data = begin = XLogRecGetBlockData(record, 0, &datalen);

		page = (Page) BufferGetPage(buffer);

		if (xldata->ntodelete == 1 && xldata->ntoinsert == 1)
		{
			/*
			 * When replacing one tuple with one other tuple, we must use
			 * PageIndexTupleOverwrite for consistency with gistplacetopage.
			 */
			OffsetNumber offnum = *((OffsetNumber *) data);
			IndexTuple	itup;
			Size		itupsize;

			data += sizeof(OffsetNumber);
			itup = (IndexTuple) data;
			itupsize = IndexTupleSize(itup);
			if (!PageIndexTupleOverwrite(page, offnum, (Item) itup, itupsize))
				elog(ERROR, "failed to add item to GiST index page, size %d bytes",
					 (int) itupsize);
			data += itupsize;
			/* should be nothing left after consuming 1 tuple */
			Assert(data - begin == datalen);
			/* update insertion count for assert check below */
			ninserted++;
		}
		else if (xldata->ntodelete > 0)
		{
			/* Otherwise, delete old tuples if any */
			OffsetNumber *todelete = (OffsetNumber *) data;

			data += sizeof(OffsetNumber) * xldata->ntodelete;

			PageIndexMultiDelete(page, todelete, xldata->ntodelete);
			if (GistPageIsLeaf(page))
				GistMarkTuplesDeleted(page);
		}

		/* Add new tuples if any */
		if (data - begin < datalen)
		{
			OffsetNumber off = (PageIsEmpty(page)) ? FirstOffsetNumber :
			OffsetNumberNext(PageGetMaxOffsetNumber(page));

			while (data - begin < datalen)
			{
				IndexTuple	itup = (IndexTuple) data;
				Size		sz = IndexTupleSize(itup);
				OffsetNumber l;

				data += sz;

				l = PageAddItem(page, (Item) itup, sz, off, false, false);
				if (l == InvalidOffsetNumber)
					elog(ERROR, "failed to add item to GiST index page, size %d bytes",
						 (int) sz);
				off++;
				ninserted++;
			}
		}

		/* Check that XLOG record contained expected number of tuples */
		Assert(ninserted == xldata->ntoinsert);

		PageSetLSN(page, lsn);
		MarkBufferDirty(buffer);
	}

	/*
	 * Fix follow-right data on left child page
	 *
	 * This must be done while still holding the lock on the target page. Note
	 * that even if the target page no longer exists, we still attempt to
	 * replay the change on the child page.
	 */
	if (XLogRecHasBlockRef(record, 1))
		gistRedoClearFollowRight(record, 1);

	if (BufferIsValid(buffer))
		UnlockReleaseBuffer(buffer);
}
Exemple #15
0
/*
 * 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;
}
Exemple #16
0
static int
gistlayerinsert(Relation r, BlockNumber blkno,
				IndexTuple **itup,		/* in - out, has compressed entry */
				int *len,		/* in - out */
				InsertIndexResult *res, /* out */
				GISTSTATE *giststate)
{
	Buffer		buffer;
	Page		page;
	OffsetNumber child;
	int			ret;
	GISTPageOpaque opaque;

	buffer = ReadBuffer(r, blkno);
	page = (Page) BufferGetPage(buffer);
	opaque = (GISTPageOpaque) PageGetSpecialPointer(page);

	if (!(opaque->flags & F_LEAF))
	{
		/* internal page, so we must walk on tree */
		/* len IS equal 1 */
		ItemId		iid;
		BlockNumber nblkno;
		ItemPointerData oldtid;
		IndexTuple	oldtup;

		child = gistchoose(r, page, *(*itup), giststate);
		iid = PageGetItemId(page, child);
		oldtup = (IndexTuple) PageGetItem(page, iid);
		nblkno = ItemPointerGetBlockNumber(&(oldtup->t_tid));

		/*
		 * After this call: 1. if child page was splited, then itup
		 * contains keys for each page 2. if  child page wasn't splited,
		 * then itup contains additional for adjustment of current key
		 */
		ret = gistlayerinsert(r, nblkno, itup, len, res, giststate);

		/* nothing inserted in child */
		if (!(ret & INSERTED))
		{
			ReleaseBuffer(buffer);
			return 0x00;
		}

		/* child does not splited */
		if (!(ret & SPLITED))
		{
			IndexTuple	newtup = gistgetadjusted(r, oldtup, (*itup)[0], giststate);

			if (!newtup)
			{
				/* not need to update key */
				ReleaseBuffer(buffer);
				return 0x00;
			}

			pfree((*itup)[0]);	/* !!! */
			(*itup)[0] = newtup;
		}

		/* key is modified, so old version must be deleted */
		ItemPointerSet(&oldtid, blkno, child);
		gistdelete(r, &oldtid);

		/*
		 * if child was splitted, new key for child will be inserted in
		 * the end list of child, so we must say to any scans that page is
		 * changed beginning from 'child' offset
		 */
		if (ret & SPLITED)
			gistadjscans(r, GISTOP_SPLIT, blkno, child);
	}

	ret = INSERTED;

	if (gistnospace(page, (*itup), *len))
	{
		/* no space for insertion */
		IndexTuple *itvec,
				   *newitup;
		int			tlen,
					oldlen;

		ret |= SPLITED;
		itvec = gistreadbuffer(buffer, &tlen);
		itvec = gistjoinvector(itvec, &tlen, (*itup), *len);
		oldlen = *len;
		newitup = gistSplit(r, buffer, itvec, &tlen, giststate,
							(opaque->flags & F_LEAF) ? res : NULL);		/* res only for
																		 * inserting in leaf */
		ReleaseBuffer(buffer);
		do
			pfree((*itup)[oldlen - 1]);
		while ((--oldlen) > 0);
		pfree((*itup));
		pfree(itvec);
		*itup = newitup;
		*len = tlen;			/* now tlen >= 2 */
	}
	else
	{
		/* enogth space */
		OffsetNumber off,
					l;

		off = (PageIsEmpty(page)) ?
			FirstOffsetNumber
			:
			OffsetNumberNext(PageGetMaxOffsetNumber(page));
		l = gistwritebuffer(r, page, (*itup), *len, off);
		WriteBuffer(buffer);

		/*
		 * set res if insert into leaf page, in this case, len = 1 always
		 */
		if (res && (opaque->flags & F_LEAF))
			ItemPointerSet(&((*res)->pointerData), blkno, l);

		if (*len > 1)
		{						/* previous insert ret & SPLITED != 0 */
			int			i;

			/*
			 * child was splited, so we must form union for insertion in
			 * parent
			 */
			IndexTuple	newtup = gistunion(r, (*itup), *len, giststate);

			ItemPointerSet(&(newtup->t_tid), blkno, 1);

			for (i = 0; i < *len; i++)
				pfree((*itup)[i]);
			(*itup)[0] = newtup;
			*len = 1;
		}
	}

	return ret;
}
Exemple #17
0
/*
 * PageIndexTupleDelete
 *
 * This routine does the work of removing a tuple from an index page.
 *
 * Unlike heap pages, we compact out the line pointer for the removed tuple.
 */
void
PageIndexTupleDelete(Page page, OffsetNumber offnum)
{
	PageHeader	phdr = (PageHeader) page;
	char	   *addr;
	ItemId		tup;
	Size		size;
	unsigned	offset;
	int			nbytes;
	int			offidx;
	int			nline;

	/*
	 * As with PageRepairFragmentation, paranoia seems justified.
	 */
	if (phdr->pd_lower < SizeOfPageHeaderData ||
		phdr->pd_lower > phdr->pd_upper ||
		phdr->pd_upper > phdr->pd_special ||
		phdr->pd_special > BLCKSZ ||
		phdr->pd_special != MAXALIGN(phdr->pd_special))
		ereport(ERROR,
				(errcode(ERRCODE_DATA_CORRUPTED),
				 errmsg("corrupted page pointers: lower = %u, upper = %u, special = %u",
						phdr->pd_lower, phdr->pd_upper, phdr->pd_special)));

	nline = PageGetMaxOffsetNumber(page);
	if ((int) offnum <= 0 || (int) offnum > nline)
		elog(ERROR, "invalid index offnum: %u", offnum);

	/* change offset number to offset index */
	offidx = offnum - 1;

	tup = PageGetItemId(page, offnum);
	Assert(ItemIdHasStorage(tup));
	size = ItemIdGetLength(tup);
	offset = ItemIdGetOffset(tup);

	if (offset < phdr->pd_upper || (offset + size) > phdr->pd_special ||
		offset != MAXALIGN(offset))
		ereport(ERROR,
				(errcode(ERRCODE_DATA_CORRUPTED),
				 errmsg("corrupted item pointer: offset = %u, size = %u",
						offset, (unsigned int) size)));

	/* Amount of space to actually be deleted */
	size = MAXALIGN(size);

	/*
	 * First, we want to get rid of the pd_linp entry for the index tuple. We
	 * copy all subsequent linp's back one slot in the array. We don't use
	 * PageGetItemId, because we are manipulating the _array_, not individual
	 * linp's.
	 */
	nbytes = phdr->pd_lower -
		((char *) &phdr->pd_linp[offidx + 1] - (char *) phdr);

	if (nbytes > 0)
		memmove((char *) &(phdr->pd_linp[offidx]),
				(char *) &(phdr->pd_linp[offidx + 1]),
				nbytes);

	/*
	 * Now move everything between the old upper bound (beginning of tuple
	 * space) and the beginning of the deleted tuple forward, so that space in
	 * the middle of the page is left free.  If we've just deleted the tuple
	 * at the beginning of tuple space, then there's no need to do the copy.
	 */

	/* beginning of tuple space */
	addr = (char *) page + phdr->pd_upper;

	if (offset > phdr->pd_upper)
		memmove(addr + size, addr, offset - phdr->pd_upper);

	/* adjust free space boundary pointers */
	phdr->pd_upper += size;
	phdr->pd_lower -= sizeof(ItemIdData);

	/*
	 * Finally, we need to adjust the linp entries that remain.
	 *
	 * Anything that used to be before the deleted tuple's data was moved
	 * forward by the size of the deleted tuple.
	 */
	if (!PageIsEmpty(page))
	{
		int			i;

		nline--;				/* there's one less than when we started */
		for (i = 1; i <= nline; i++)
		{
			ItemId		ii = PageGetItemId(phdr, i);

			Assert(ItemIdHasStorage(ii));
			if (ItemIdGetOffset(ii) <= offset)
				ii->lp_off += size;
		}
	}
}
Exemple #18
0
/*
 * redo any page update (except page split)
 */
static void
gistRedoPageUpdateRecord(XLogRecPtr lsn, XLogRecord *record)
{
	char	   *begin = XLogRecGetData(record);
	gistxlogPageUpdate *xldata = (gistxlogPageUpdate *) begin;
	Buffer		buffer;
	Page		page;
	char	   *data;

	if (BlockNumberIsValid(xldata->leftchild))
		gistRedoClearFollowRight(xldata->node, lsn, xldata->leftchild);

	/* nothing more to do if page was backed up (and no info to do it with) */
	if (record->xl_info & XLR_BKP_BLOCK_1)
		return;

	buffer = XLogReadBuffer(xldata->node, xldata->blkno, false);
	if (!BufferIsValid(buffer))
		return;
	page = (Page) BufferGetPage(buffer);

	if (XLByteLE(lsn, PageGetLSN(page)))
	{
		UnlockReleaseBuffer(buffer);
		return;
	}

	data = begin + sizeof(gistxlogPageUpdate);

	/* Delete old tuples */
	if (xldata->ntodelete > 0)
	{
		int			i;
		OffsetNumber *todelete = (OffsetNumber *) data;

		data += sizeof(OffsetNumber) * xldata->ntodelete;

		for (i = 0; i < xldata->ntodelete; i++)
			PageIndexTupleDelete(page, todelete[i]);
		if (GistPageIsLeaf(page))
			GistMarkTuplesDeleted(page);
	}

	/* add tuples */
	if (data - begin < record->xl_len)
	{
		OffsetNumber off = (PageIsEmpty(page)) ? FirstOffsetNumber :
		OffsetNumberNext(PageGetMaxOffsetNumber(page));

		while (data - begin < record->xl_len)
		{
			IndexTuple	itup = (IndexTuple) data;
			Size		sz = IndexTupleSize(itup);
			OffsetNumber l;

			data += sz;

			l = PageAddItem(page, (Item) itup, sz, off, false, false);
			if (l == InvalidOffsetNumber)
				elog(ERROR, "failed to add item to GiST index page, size %d bytes",
					 (int) sz);
			off++;
		}
	}
	else
	{
		/*
		 * special case: leafpage, nothing to insert, nothing to delete, then
		 * vacuum marks page
		 */
		if (GistPageIsLeaf(page) && xldata->ntodelete == 0)
			GistClearTuplesDeleted(page);
	}

	if (!GistPageIsLeaf(page) && PageGetMaxOffsetNumber(page) == InvalidOffsetNumber && xldata->blkno == GIST_ROOT_BLKNO)

		/*
		 * all links on non-leaf root page was deleted by vacuum full, so root
		 * page becomes a leaf
		 */
		GistPageSetLeaf(page);

	GistPageGetOpaque(page)->rightlink = InvalidBlockNumber;
	PageSetLSN(page, lsn);
	PageSetTLI(page, ThisTimeLineID);
	MarkBufferDirty(buffer);
	UnlockReleaseBuffer(buffer);
}
Exemple #19
0
/*
 * Get a buffer of the type and parity specified by flags, having at least
 * as much free space as indicated by needSpace.  We use the lastUsedPages
 * cache to assign the same buffer previously requested when possible.
 * The returned buffer is already pinned and exclusive-locked.
 *
 * *isNew is set true if the page was initialized here, false if it was
 * already valid.
 */
Buffer
SpGistGetBuffer(Relation index, int flags, int needSpace, bool *isNew)
{
	SpGistCache *cache = spgGetCache(index);
	SpGistLastUsedPage *lup;

	/* Bail out if even an empty page wouldn't meet the demand */
	if (needSpace > SPGIST_PAGE_CAPACITY)
		elog(ERROR, "desired SPGiST tuple size is too big");

	/*
	 * If possible, increase the space request to include relation's
	 * fillfactor.	This ensures that when we add unrelated tuples to a page,
	 * we try to keep 100-fillfactor% available for adding tuples that are
	 * related to the ones already on it.  But fillfactor mustn't cause an
	 * error for requests that would otherwise be legal.
	 */
	needSpace += RelationGetTargetPageFreeSpace(index,
												SPGIST_DEFAULT_FILLFACTOR);
	needSpace = Min(needSpace, SPGIST_PAGE_CAPACITY);

	/* Get the cache entry for this flags setting */
	lup = GET_LUP(cache, flags);

	/* If we have nothing cached, just turn it over to allocNewBuffer */
	if (lup->blkno == InvalidBlockNumber)
	{
		*isNew = true;
		return allocNewBuffer(index, flags);
	}

	/* fixed pages should never be in cache */
	Assert(!SpGistBlockIsFixed(lup->blkno));

	/* If cached freeSpace isn't enough, don't bother looking at the page */
	if (lup->freeSpace >= needSpace)
	{
		Buffer		buffer;
		Page		page;

		buffer = ReadBuffer(index, lup->blkno);

		if (!ConditionalLockBuffer(buffer))
		{
			/*
			 * buffer is locked by another process, so return a new buffer
			 */
			ReleaseBuffer(buffer);
			*isNew = true;
			return allocNewBuffer(index, flags);
		}

		page = BufferGetPage(buffer);

		if (PageIsNew(page) || SpGistPageIsDeleted(page) || PageIsEmpty(page))
		{
			/* OK to initialize the page */
			uint16		pageflags = 0;

			if (GBUF_REQ_LEAF(flags))
				pageflags |= SPGIST_LEAF;
			if (GBUF_REQ_NULLS(flags))
				pageflags |= SPGIST_NULLS;
			SpGistInitBuffer(buffer, pageflags);
			lup->freeSpace = PageGetExactFreeSpace(page) - needSpace;
			*isNew = true;
			return buffer;
		}

		/*
		 * Check that page is of right type and has enough space.  We must
		 * recheck this since our cache isn't necessarily up to date.
		 */
		if ((GBUF_REQ_LEAF(flags) ? SpGistPageIsLeaf(page) : !SpGistPageIsLeaf(page)) &&
			(GBUF_REQ_NULLS(flags) ? SpGistPageStoresNulls(page) : !SpGistPageStoresNulls(page)))
		{
			int			freeSpace = PageGetExactFreeSpace(page);

			if (freeSpace >= needSpace)
			{
				/* Success, update freespace info and return the buffer */
				lup->freeSpace = freeSpace - needSpace;
				*isNew = false;
				return buffer;
			}
		}

		/*
		 * fallback to allocation of new buffer
		 */
		UnlockReleaseBuffer(buffer);
	}

	/* No success with cache, so return a new buffer */
	*isNew = true;
	return allocNewBuffer(index, flags);
}
Exemple #20
0
/*
 *	_hash_squeezebucket(rel, bucket)
 *
 *	Try to squeeze the tuples onto pages occurring earlier in the
 *	bucket chain in an attempt to free overflow pages. When we start
 *	the "squeezing", the page from which we start taking tuples (the
 *	"read" page) is the last bucket in the bucket chain and the page
 *	onto which we start squeezing tuples (the "write" page) is the
 *	first page in the bucket chain.  The read page works backward and
 *	the write page works forward; the procedure terminates when the
 *	read page and write page are the same page.
 *
 *	At completion of this procedure, it is guaranteed that all pages in
 *	the bucket are nonempty, unless the bucket is totally empty (in
 *	which case all overflow pages will be freed).  The original implementation
 *	required that to be true on entry as well, but it's a lot easier for
 *	callers to leave empty overflow pages and let this guy clean it up.
 *
 *	Caller must acquire cleanup lock on the primary page of the target
 *	bucket to exclude any scans that are in progress, which could easily
 *	be confused into returning the same tuple more than once or some tuples
 *	not at all by the rearrangement we are performing here.  To prevent
 *	any concurrent scan to cross the squeeze scan we use lock chaining
 *	similar to hasbucketcleanup.  Refer comments atop hashbucketcleanup.
 *
 *	We need to retain a pin on the primary bucket to ensure that no concurrent
 *	split can start.
 *
 *	Since this function is invoked in VACUUM, we provide an access strategy
 *	parameter that controls fetches of the bucket pages.
 */
void
_hash_squeezebucket(Relation rel,
					Bucket bucket,
					BlockNumber bucket_blkno,
					Buffer bucket_buf,
					BufferAccessStrategy bstrategy)
{
	BlockNumber wblkno;
	BlockNumber rblkno;
	Buffer		wbuf;
	Buffer		rbuf;
	Page		wpage;
	Page		rpage;
	HashPageOpaque wopaque;
	HashPageOpaque ropaque;

	/*
	 * start squeezing into the primary bucket page.
	 */
	wblkno = bucket_blkno;
	wbuf = bucket_buf;
	wpage = BufferGetPage(wbuf);
	wopaque = (HashPageOpaque) PageGetSpecialPointer(wpage);

	/*
	 * if there aren't any overflow pages, there's nothing to squeeze. caller
	 * is responsible for releasing the pin on primary bucket page.
	 */
	if (!BlockNumberIsValid(wopaque->hasho_nextblkno))
	{
		LockBuffer(wbuf, BUFFER_LOCK_UNLOCK);
		return;
	}

	/*
	 * Find the last page in the bucket chain by starting at the base bucket
	 * page and working forward.  Note: we assume that a hash bucket chain is
	 * usually smaller than the buffer ring being used by VACUUM, else using
	 * the access strategy here would be counterproductive.
	 */
	rbuf = InvalidBuffer;
	ropaque = wopaque;
	do
	{
		rblkno = ropaque->hasho_nextblkno;
		if (rbuf != InvalidBuffer)
			_hash_relbuf(rel, rbuf);
		rbuf = _hash_getbuf_with_strategy(rel,
										  rblkno,
										  HASH_WRITE,
										  LH_OVERFLOW_PAGE,
										  bstrategy);
		rpage = BufferGetPage(rbuf);
		ropaque = (HashPageOpaque) PageGetSpecialPointer(rpage);
		Assert(ropaque->hasho_bucket == bucket);
	} while (BlockNumberIsValid(ropaque->hasho_nextblkno));

	/*
	 * squeeze the tuples.
	 */
	for (;;)
	{
		OffsetNumber roffnum;
		OffsetNumber maxroffnum;
		OffsetNumber deletable[MaxOffsetNumber];
		IndexTuple	itups[MaxIndexTuplesPerPage];
		Size		tups_size[MaxIndexTuplesPerPage];
		OffsetNumber itup_offsets[MaxIndexTuplesPerPage];
		uint16		ndeletable = 0;
		uint16		nitups = 0;
		Size		all_tups_size = 0;
		int			i;
		bool		retain_pin = false;

readpage:
		/* Scan each tuple in "read" page */
		maxroffnum = PageGetMaxOffsetNumber(rpage);
		for (roffnum = FirstOffsetNumber;
			 roffnum <= maxroffnum;
			 roffnum = OffsetNumberNext(roffnum))
		{
			IndexTuple	itup;
			Size		itemsz;

			/* skip dead tuples */
			if (ItemIdIsDead(PageGetItemId(rpage, roffnum)))
				continue;

			itup = (IndexTuple) PageGetItem(rpage,
											PageGetItemId(rpage, roffnum));
			itemsz = IndexTupleDSize(*itup);
			itemsz = MAXALIGN(itemsz);

			/*
			 * Walk up the bucket chain, looking for a page big enough for
			 * this item and all other accumulated items.  Exit if we reach
			 * the read page.
			 */
			while (PageGetFreeSpaceForMultipleTuples(wpage, nitups + 1) < (all_tups_size + itemsz))
			{
				Buffer		next_wbuf = InvalidBuffer;
				bool		tups_moved = false;

				Assert(!PageIsEmpty(wpage));

				if (wblkno == bucket_blkno)
					retain_pin = true;

				wblkno = wopaque->hasho_nextblkno;
				Assert(BlockNumberIsValid(wblkno));

				/* don't need to move to next page if we reached the read page */
				if (wblkno != rblkno)
					next_wbuf = _hash_getbuf_with_strategy(rel,
														   wblkno,
														   HASH_WRITE,
														   LH_OVERFLOW_PAGE,
														   bstrategy);

				if (nitups > 0)
				{
					Assert(nitups == ndeletable);

					/*
					 * This operation needs to log multiple tuples, prepare
					 * WAL for that.
					 */
					if (RelationNeedsWAL(rel))
						XLogEnsureRecordSpace(0, 3 + nitups);

					START_CRIT_SECTION();

					/*
					 * we have to insert tuples on the "write" page, being
					 * careful to preserve hashkey ordering.  (If we insert
					 * many tuples into the same "write" page it would be
					 * worth qsort'ing them).
					 */
					_hash_pgaddmultitup(rel, wbuf, itups, itup_offsets, nitups);
					MarkBufferDirty(wbuf);

					/* Delete tuples we already moved off read page */
					PageIndexMultiDelete(rpage, deletable, ndeletable);
					MarkBufferDirty(rbuf);

					/* XLOG stuff */
					if (RelationNeedsWAL(rel))
					{
						XLogRecPtr	recptr;
						xl_hash_move_page_contents xlrec;

						xlrec.ntups = nitups;
						xlrec.is_prim_bucket_same_wrt = (wbuf == bucket_buf) ? true : false;

						XLogBeginInsert();
						XLogRegisterData((char *) &xlrec, SizeOfHashMovePageContents);

						/*
						 * bucket buffer needs to be registered to ensure that
						 * we can acquire a cleanup lock on it during replay.
						 */
						if (!xlrec.is_prim_bucket_same_wrt)
							XLogRegisterBuffer(0, bucket_buf, REGBUF_STANDARD | REGBUF_NO_IMAGE);

						XLogRegisterBuffer(1, wbuf, REGBUF_STANDARD);
						XLogRegisterBufData(1, (char *) itup_offsets,
											nitups * sizeof(OffsetNumber));
						for (i = 0; i < nitups; i++)
							XLogRegisterBufData(1, (char *) itups[i], tups_size[i]);

						XLogRegisterBuffer(2, rbuf, REGBUF_STANDARD);
						XLogRegisterBufData(2, (char *) deletable,
											ndeletable * sizeof(OffsetNumber));

						recptr = XLogInsert(RM_HASH_ID, XLOG_HASH_MOVE_PAGE_CONTENTS);

						PageSetLSN(BufferGetPage(wbuf), recptr);
						PageSetLSN(BufferGetPage(rbuf), recptr);
					}

					END_CRIT_SECTION();

					tups_moved = true;
				}

				/*
				 * release the lock on previous page after acquiring the lock
				 * on next page
				 */
				if (retain_pin)
					LockBuffer(wbuf, BUFFER_LOCK_UNLOCK);
				else
					_hash_relbuf(rel, wbuf);

				/* nothing more to do if we reached the read page */
				if (rblkno == wblkno)
				{
					_hash_relbuf(rel, rbuf);
					return;
				}

				wbuf = next_wbuf;
				wpage = BufferGetPage(wbuf);
				wopaque = (HashPageOpaque) PageGetSpecialPointer(wpage);
				Assert(wopaque->hasho_bucket == bucket);
				retain_pin = false;

				/* be tidy */
				for (i = 0; i < nitups; i++)
					pfree(itups[i]);
				nitups = 0;
				all_tups_size = 0;
				ndeletable = 0;

				/*
				 * after moving the tuples, rpage would have been compacted,
				 * so we need to rescan it.
				 */
				if (tups_moved)
					goto readpage;
			}

			/* remember tuple for deletion from "read" page */
			deletable[ndeletable++] = roffnum;

			/*
			 * we need a copy of index tuples as they can be freed as part of
			 * overflow page, however we need them to write a WAL record in
			 * _hash_freeovflpage.
			 */
			itups[nitups] = CopyIndexTuple(itup);
			tups_size[nitups++] = itemsz;
			all_tups_size += itemsz;
		}

		/*
		 * If we reach here, there are no live tuples on the "read" page ---
		 * it was empty when we got to it, or we moved them all.  So we can
		 * just free the page without bothering with deleting tuples
		 * individually.  Then advance to the previous "read" page.
		 *
		 * Tricky point here: if our read and write pages are adjacent in the
		 * bucket chain, our write lock on wbuf will conflict with
		 * _hash_freeovflpage's attempt to update the sibling links of the
		 * removed page.  In that case, we don't need to lock it again.
		 */
		rblkno = ropaque->hasho_prevblkno;
		Assert(BlockNumberIsValid(rblkno));

		/* free this overflow page (releases rbuf) */
		_hash_freeovflpage(rel, bucket_buf, rbuf, wbuf, itups, itup_offsets,
						   tups_size, nitups, bstrategy);

		/* be tidy */
		for (i = 0; i < nitups; i++)
			pfree(itups[i]);

		/* are we freeing the page adjacent to wbuf? */
		if (rblkno == wblkno)
		{
			/* retain the pin on primary bucket page till end of bucket scan */
			if (wblkno == bucket_blkno)
				LockBuffer(wbuf, BUFFER_LOCK_UNLOCK);
			else
				_hash_relbuf(rel, wbuf);
			return;
		}

		rbuf = _hash_getbuf_with_strategy(rel,
										  rblkno,
										  HASH_WRITE,
										  LH_OVERFLOW_PAGE,
										  bstrategy);
		rpage = BufferGetPage(rbuf);
		ropaque = (HashPageOpaque) PageGetSpecialPointer(rpage);
		Assert(ropaque->hasho_bucket == bucket);
	}

	/* NOTREACHED */
}
Exemple #21
0
/*
 * 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;
}
Exemple #22
0
/*
 * Fetch a tuples that matchs the search key; this can be invoked
 * either to fetch the first such tuple or subsequent matching
 * tuples. Returns true iff a matching tuple was found.
 */
static int
gistnext(IndexScanDesc scan, ScanDirection dir, ItemPointer tids,
		 int maxtids, bool ignore_killed_tuples)
{
	MIRROREDLOCK_BUFMGR_DECLARE;

	Page		p;
	OffsetNumber n;
	GISTScanOpaque so;
	GISTSearchStack *stk;
	IndexTuple	it;
	GISTPageOpaque opaque;
	int			ntids = 0;

	so = (GISTScanOpaque) scan->opaque;

	// -------- MirroredLock ----------
	MIRROREDLOCK_BUFMGR_LOCK;

	if ( so->qual_ok == false )
		return 0;

	if (ItemPointerIsValid(&so->curpos) == false)
	{
		/* Being asked to fetch the first entry, so start at the root */
		Assert(so->curbuf == InvalidBuffer);
		Assert(so->stack == NULL);

		so->curbuf = ReadBuffer(scan->indexRelation, GIST_ROOT_BLKNO);

		stk = so->stack = (GISTSearchStack *) palloc0(sizeof(GISTSearchStack));

		stk->next = NULL;
		stk->block = GIST_ROOT_BLKNO;

		pgstat_count_index_scan(scan->indexRelation);
	}
	else if (so->curbuf == InvalidBuffer)
	{
		MIRROREDLOCK_BUFMGR_UNLOCK;
		// -------- MirroredLock ----------

		return 0;
	}

	/*
	 * check stored pointers from last visit 
	 */
	if ( so->nPageData > 0 ) 
	{
		while( ntids < maxtids && so->curPageData < so->nPageData )
		{
			tids[ ntids ] = scan->xs_ctup.t_self = so->pageData[ so->curPageData ].heapPtr;
			ItemPointerSet(&(so->curpos),
							   BufferGetBlockNumber(so->curbuf), 
							   so->pageData[ so->curPageData ].pageOffset);

				
			so->curPageData ++;
			ntids++;
		}

		if ( ntids == maxtids )
		{
			MIRROREDLOCK_BUFMGR_UNLOCK;
			// -------- MirroredLock ----------

			return ntids;
		}
		
		/*
		 * Go to the next page
		 */
		stk = so->stack->next;
		pfree(so->stack);
		so->stack = stk;

		/* If we're out of stack entries, we're done */
		if (so->stack == NULL)
		{
			ReleaseBuffer(so->curbuf);
			so->curbuf = InvalidBuffer;

			MIRROREDLOCK_BUFMGR_UNLOCK;
			// -------- MirroredLock ----------

			return ntids;
		}

		so->curbuf = ReleaseAndReadBuffer(so->curbuf,
										  scan->indexRelation,
										  stk->block);
	}

	for (;;)
	{
		/* First of all, we need lock buffer */
		Assert(so->curbuf != InvalidBuffer);
		LockBuffer(so->curbuf, GIST_SHARE);
		gistcheckpage(scan->indexRelation, so->curbuf);
		p = BufferGetPage(so->curbuf);
		opaque = GistPageGetOpaque(p);

		/* remember lsn to identify page changed for tuple's killing */
		so->stack->lsn = PageGetLSN(p);

		/* check page split, occured from last visit or visit to parent */
		if (!XLogRecPtrIsInvalid(so->stack->parentlsn) &&
			XLByteLT(so->stack->parentlsn, opaque->nsn) &&
			opaque->rightlink != InvalidBlockNumber /* sanity check */ &&
			(so->stack->next == NULL || so->stack->next->block != opaque->rightlink)		/* check if already
					added */ )
		{
			/* detect page split, follow right link to add pages */

			stk = (GISTSearchStack *) palloc(sizeof(GISTSearchStack));
			stk->next = so->stack->next;
			stk->block = opaque->rightlink;
			stk->parentlsn = so->stack->parentlsn;
			memset(&(stk->lsn), 0, sizeof(GistNSN));
			so->stack->next = stk;
		}

		/* if page is empty, then just skip it */
		if (PageIsEmpty(p))
		{
			LockBuffer(so->curbuf, GIST_UNLOCK);
			stk = so->stack->next;
			pfree(so->stack);
			so->stack = stk;

			if (so->stack == NULL)
			{
				ReleaseBuffer(so->curbuf);
				so->curbuf = InvalidBuffer;

				MIRROREDLOCK_BUFMGR_UNLOCK;
				// -------- MirroredLock ----------

				return ntids;
			}

			so->curbuf = ReleaseAndReadBuffer(so->curbuf, scan->indexRelation,
											  stk->block);
			continue;
		}

		if (ScanDirectionIsBackward(dir))
			n = PageGetMaxOffsetNumber(p);
		else
			n = FirstOffsetNumber;

		/* wonderful, we can look at page */
		so->nPageData = so->curPageData = 0;

		for (;;)
		{
			n = gistfindnext(scan, n, dir);

			if (!OffsetNumberIsValid(n))
			{
				while( ntids < maxtids && so->curPageData < so->nPageData )
				{
					tids[ ntids ] = scan->xs_ctup.t_self = 
						so->pageData[ so->curPageData ].heapPtr;
				
					ItemPointerSet(&(so->curpos),
								   BufferGetBlockNumber(so->curbuf), 
								   so->pageData[ so->curPageData ].pageOffset);

					so->curPageData ++;
					ntids++;
				}

				if ( ntids == maxtids )
				{
					LockBuffer(so->curbuf, GIST_UNLOCK);
					
					MIRROREDLOCK_BUFMGR_UNLOCK;
					// -------- MirroredLock ----------
					
					return ntids;
				}

				/*
				 * We ran out of matching index entries on the current page,
				 * so pop the top stack entry and use it to continue the
				 * search.
				 */
				LockBuffer(so->curbuf, GIST_UNLOCK);
				stk = so->stack->next;
				pfree(so->stack);
				so->stack = stk;

				/* If we're out of stack entries, we're done */

				if (so->stack == NULL)
				{
					ReleaseBuffer(so->curbuf);
					so->curbuf = InvalidBuffer;
					
					MIRROREDLOCK_BUFMGR_UNLOCK;
					// -------- MirroredLock ----------
					
					return ntids;
				}

				so->curbuf = ReleaseAndReadBuffer(so->curbuf,
												  scan->indexRelation,
												  stk->block);
				/* XXX	go up */
				break;
			}

			if (GistPageIsLeaf(p))
			{
				/*
				 * We've found a matching index entry in a leaf page, so
				 * return success. Note that we keep "curbuf" pinned so that
				 * we can efficiently resume the index scan later.
				 */

				if (!(ignore_killed_tuples && ItemIdIsDead(PageGetItemId(p, n))))
				{
					it = (IndexTuple) PageGetItem(p, PageGetItemId(p, n));
					so->pageData[ so->nPageData ].heapPtr = it->t_tid;
					so->pageData[ so->nPageData ].pageOffset = n;
					so->nPageData ++;
				}
			}
			else
			{
				/*
				 * We've found an entry in an internal node whose key is
				 * consistent with the search key, so push it to stack
				 */

				stk = (GISTSearchStack *) palloc(sizeof(GISTSearchStack));

				it = (IndexTuple) PageGetItem(p, PageGetItemId(p, n));
				stk->block = ItemPointerGetBlockNumber(&(it->t_tid));
				memset(&(stk->lsn), 0, sizeof(GistNSN));
				stk->parentlsn = so->stack->lsn;

				stk->next = so->stack->next;
				so->stack->next = stk;

			}

			if (ScanDirectionIsBackward(dir))
				n = OffsetNumberPrev(n);
			else
				n = OffsetNumberNext(n);
		}
	}

	MIRROREDLOCK_BUFMGR_UNLOCK;
	// -------- MirroredLock ----------

	return ntids;
}
Exemple #23
0
static void
rtdoinsert(Relation r, IndexTuple itup, RTSTATE *rtstate)
{
	Page		page;
	Buffer		buffer;
	BlockNumber blk;
	IndexTuple	which;
	OffsetNumber l;
	RTSTACK    *stack;
	RTreePageOpaque opaque;
	Datum		datum;

	blk = P_ROOT;
	buffer = InvalidBuffer;
	stack = NULL;

	do
	{
		/* release the current buffer, read in the next one */
		buffer = ReleaseAndReadBuffer(buffer, r, blk);
		page = (Page) BufferGetPage(buffer);

		opaque = (RTreePageOpaque) PageGetSpecialPointer(page);
		if (!(opaque->flags & F_LEAF))
		{
			RTSTACK    *n;
			ItemId		iid;

			n = (RTSTACK *) palloc(sizeof(RTSTACK));
			n->rts_parent = stack;
			n->rts_blk = blk;
			n->rts_child = choose(r, page, itup, rtstate);
			stack = n;

			iid = PageGetItemId(page, n->rts_child);
			which = (IndexTuple) PageGetItem(page, iid);
			blk = ItemPointerGetBlockNumber(&(which->t_tid));
		}
	} while (!(opaque->flags & F_LEAF));

	if (nospace(page, itup))
	{
		/* need to do a split */
		rtdosplit(r, buffer, stack, itup, rtstate);
		freestack(stack);
		WriteBuffer(buffer);	/* don't forget to release buffer! */
		return;
	}

	/* add the item and write the buffer */
	if (PageIsEmpty(page))
	{
		l = PageAddItem(page, (Item) itup, IndexTupleSize(itup),
						FirstOffsetNumber,
						LP_USED);
	}
	else
	{
		l = PageAddItem(page, (Item) itup, IndexTupleSize(itup),
						OffsetNumberNext(PageGetMaxOffsetNumber(page)),
						LP_USED);
	}
	if (l == InvalidOffsetNumber)
		elog(ERROR, "failed to add index item to \"%s\"",
			 RelationGetRelationName(r));

	WriteBuffer(buffer);

	datum = IndexTupleGetDatum(itup);

	/* now expand the page boundary in the parent to include the new child */
	rttighten(r, stack, datum, IndexTupleAttSize(itup), rtstate);
	freestack(stack);
}
Exemple #24
0
/*
 * redo any page update (except page split)
 */
static void
gistRedoPageUpdateRecord(XLogRecPtr lsn, XLogRecord *record)
{
	char	   *begin = XLogRecGetData(record);
	gistxlogPageUpdate *xldata = (gistxlogPageUpdate *) begin;
	Buffer		buffer;
	Page		page;
	char	   *data;

	/*
	 * We need to acquire and hold lock on target page while updating the left
	 * child page.	If we have a full-page image of target page, getting the
	 * lock is a side-effect of restoring that image.  Note that even if the
	 * target page no longer exists, we'll still attempt to replay the change
	 * on the child page.
	 */
	if (record->xl_info & XLR_BKP_BLOCK(0))
		buffer = RestoreBackupBlock(lsn, record, 0, false, true);
	else
		buffer = XLogReadBuffer(xldata->node, xldata->blkno, false);

	/* Fix follow-right data on left child page */
	if (BlockNumberIsValid(xldata->leftchild))
		gistRedoClearFollowRight(lsn, record, 1,
								 xldata->node, xldata->leftchild);

	/* Done if target page no longer exists */
	if (!BufferIsValid(buffer))
		return;

	/* nothing more to do if page was backed up (and no info to do it with) */
	if (record->xl_info & XLR_BKP_BLOCK(0))
	{
		UnlockReleaseBuffer(buffer);
		return;
	}

	page = (Page) BufferGetPage(buffer);

	/* nothing more to do if change already applied */
	if (lsn <= PageGetLSN(page))
	{
		UnlockReleaseBuffer(buffer);
		return;
	}

	data = begin + sizeof(gistxlogPageUpdate);

	/* Delete old tuples */
	if (xldata->ntodelete > 0)
	{
		int			i;
		OffsetNumber *todelete = (OffsetNumber *) data;

		data += sizeof(OffsetNumber) * xldata->ntodelete;

		for (i = 0; i < xldata->ntodelete; i++)
			PageIndexTupleDelete(page, todelete[i]);
		if (GistPageIsLeaf(page))
			GistMarkTuplesDeleted(page);
	}

	/* add tuples */
	if (data - begin < record->xl_len)
	{
		OffsetNumber off = (PageIsEmpty(page)) ? FirstOffsetNumber :
		OffsetNumberNext(PageGetMaxOffsetNumber(page));

		while (data - begin < record->xl_len)
		{
			IndexTuple	itup = (IndexTuple) data;
			Size		sz = IndexTupleSize(itup);
			OffsetNumber l;

			data += sz;

			l = PageAddItem(page, (Item) itup, sz, off, false, false);
			if (l == InvalidOffsetNumber)
				elog(ERROR, "failed to add item to GiST index page, size %d bytes",
					 (int) sz);
			off++;
		}
	}
	else
	{
		/*
		 * special case: leafpage, nothing to insert, nothing to delete, then
		 * vacuum marks page
		 */
		if (GistPageIsLeaf(page) && xldata->ntodelete == 0)
			GistClearTuplesDeleted(page);
	}

	if (!GistPageIsLeaf(page) &&
		PageGetMaxOffsetNumber(page) == InvalidOffsetNumber &&
		xldata->blkno == GIST_ROOT_BLKNO)
	{
		/*
		 * all links on non-leaf root page was deleted by vacuum full, so root
		 * page becomes a leaf
		 */
		GistPageSetLeaf(page);
	}

	GistPageGetOpaque(page)->rightlink = InvalidBlockNumber;
	PageSetLSN(page, lsn);
	MarkBufferDirty(buffer);
	UnlockReleaseBuffer(buffer);
}
Exemple #25
0
/*
 * PageIndexTupleDeleteNoCompact
 *
 * Remove the specified tuple from an index page, but set its line pointer
 * to "unused" instead of compacting it out, except that it can be removed
 * if it's the last line pointer on the page.
 *
 * This is used for index AMs that require that existing TIDs of live tuples
 * remain unchanged, and are willing to allow unused line pointers instead.
 */
void
PageIndexTupleDeleteNoCompact(Page page, OffsetNumber offnum)
{
	PageHeader	phdr = (PageHeader) page;
	char	   *addr;
	ItemId		tup;
	Size		size;
	unsigned	offset;
	int			nline;

	/*
	 * As with PageRepairFragmentation, paranoia seems justified.
	 */
	if (phdr->pd_lower < SizeOfPageHeaderData ||
		phdr->pd_lower > phdr->pd_upper ||
		phdr->pd_upper > phdr->pd_special ||
		phdr->pd_special > BLCKSZ ||
		phdr->pd_special != MAXALIGN(phdr->pd_special))
		ereport(ERROR,
				(errcode(ERRCODE_DATA_CORRUPTED),
				 errmsg("corrupted page pointers: lower = %u, upper = %u, special = %u",
						phdr->pd_lower, phdr->pd_upper, phdr->pd_special)));

	nline = PageGetMaxOffsetNumber(page);
	if ((int) offnum <= 0 || (int) offnum > nline)
		elog(ERROR, "invalid index offnum: %u", offnum);

	tup = PageGetItemId(page, offnum);
	Assert(ItemIdHasStorage(tup));
	size = ItemIdGetLength(tup);
	offset = ItemIdGetOffset(tup);

	if (offset < phdr->pd_upper || (offset + size) > phdr->pd_special ||
		offset != MAXALIGN(offset))
		ereport(ERROR,
				(errcode(ERRCODE_DATA_CORRUPTED),
				 errmsg("corrupted item pointer: offset = %u, size = %u",
						offset, (unsigned int) size)));

	/* Amount of space to actually be deleted */
	size = MAXALIGN(size);

	/*
	 * Either set the item pointer to "unused", or zap it if it's the last
	 * one.  (Note: it's possible that the next-to-last one(s) are already
	 * unused, but we do not trouble to try to compact them out if so.)
	 */
	if ((int) offnum < nline)
		ItemIdSetUnused(tup);
	else
	{
		phdr->pd_lower -= sizeof(ItemIdData);
		nline--;				/* there's one less than when we started */
	}

	/*
	 * Now move everything between the old upper bound (beginning of tuple
	 * space) and the beginning of the deleted tuple forward, so that space in
	 * the middle of the page is left free.  If we've just deleted the tuple
	 * at the beginning of tuple space, then there's no need to do the copy.
	 */

	/* beginning of tuple space */
	addr = (char *) page + phdr->pd_upper;

	if (offset > phdr->pd_upper)
		memmove(addr + size, addr, offset - phdr->pd_upper);

	/* adjust free space boundary pointer */
	phdr->pd_upper += size;

	/*
	 * Finally, we need to adjust the linp entries that remain.
	 *
	 * Anything that used to be before the deleted tuple's data was moved
	 * forward by the size of the deleted tuple.
	 */
	if (!PageIsEmpty(page))
	{
		int			i;

		for (i = 1; i <= nline; i++)
		{
			ItemId		ii = PageGetItemId(phdr, i);

			if (ItemIdHasStorage(ii) && ItemIdGetOffset(ii) <= offset)
				ii->lp_off += size;
		}
	}
}
Exemple #26
0
/*
 *	lazy_scan_heap() -- scan an open heap relation
 *
 *		This routine sets commit status bits, builds lists of dead tuples
 *		and pages with free space, and calculates statistics on the number
 *		of live tuples in the heap.  When done, or when we run low on space
 *		for dead-tuple TIDs, invoke vacuuming of indexes and heap.
 *
 *		If there are no indexes then we just vacuum each dirty page as we
 *		process it, since there's no point in gathering many tuples.
 */
static void
lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
			   Relation *Irel, int nindexes, List *updated_stats)
{
	MIRROREDLOCK_BUFMGR_DECLARE;

	BlockNumber nblocks,
				blkno;
	HeapTupleData tuple;
	char	   *relname;
	BlockNumber empty_pages,
				vacuumed_pages;
	double		num_tuples,
				tups_vacuumed,
				nkeep,
				nunused;
	IndexBulkDeleteResult **indstats;
	int			i;
	int reindex_count = 1;
	PGRUsage	ru0;

	/* Fetch gp_persistent_relation_node information that will be added to XLOG record. */
	RelationFetchGpRelationNodeForXLog(onerel);

	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->nonempty_pages = 0;

	lazy_space_alloc(vacrelstats, nblocks);

	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;

		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)
		{
			/* Remove index entries */
			for (i = 0; i < nindexes; i++)
				lazy_vacuum_index(Irel[i], &indstats[i], vacrelstats);

			reindex_count++;

			/* Remove tuples from heap */
			lazy_vacuum_heap(onerel, vacrelstats);
			/* Forget the now-vacuumed tuples, and press on */
			vacrelstats->num_dead_tuples = 0;
			vacrelstats->num_index_scans++;
		}

		/* -------- MirroredLock ---------- */
		MIRROREDLOCK_BUFMGR_LOCK;

		buf = ReadBufferWithStrategy(onerel, blkno, vac_strategy);

		/* We need buffer cleanup lock so that we can prune HOT chains. */
		LockBufferForCleanup(buf);

		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);

			MIRROREDLOCK_BUFMGR_UNLOCK;
			/* -------- MirroredLock ---------- */

			LockRelationForExtension(onerel, ExclusiveLock);
			UnlockRelationForExtension(onerel, ExclusiveLock);

			/* -------- MirroredLock ---------- */
			MIRROREDLOCK_BUFMGR_LOCK;

			LockBufferForCleanup(buf);
			if (PageIsNew(page))
			{
				ereport(WARNING,
				(errmsg("relation \"%s\" page %u is uninitialized --- fixing",
						relname, blkno)));
				PageInit(page, BufferGetPageSize(buf), 0);

				/* must record in xlog so that changetracking will know about this change */
				log_heap_newpage(onerel, page, blkno);

				empty_pages++;
				lazy_record_free_space(vacrelstats, blkno,
									   PageGetHeapFreeSpace(page));
			}
			MarkBufferDirty(buf);
			UnlockReleaseBuffer(buf);

			MIRROREDLOCK_BUFMGR_UNLOCK;
			/* -------- MirroredLock ---------- */

			continue;
		}

		if (PageIsEmpty(page))
		{
			empty_pages++;
			lazy_record_free_space(vacrelstats, blkno,
								   PageGetHeapFreeSpace(page));
			UnlockReleaseBuffer(buf);

			MIRROREDLOCK_BUFMGR_UNLOCK;
			/* -------- MirroredLock ---------- */

			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, false);

		/*
		 * Now scan the page to collect vacuumable items and check for tuples
		 * requiring freezing.
		 */
		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));
				continue;
			}

			Assert(ItemIdIsNormal(itemid));

			tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
			tuple.t_len = ItemIdGetLength(itemid);

			tupgone = false;

			switch (HeapTupleSatisfiesVacuum(onerel, 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 */
					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);
					break;
				case HEAPTUPLE_RECENTLY_DEAD:

					/*
					 * If tuple is recently deleted then we must not remove it
					 * from relation.
					 */
					nkeep += 1;
					break;
				case HEAPTUPLE_INSERT_IN_PROGRESS:
					/* This is an expected case during concurrent vacuum */
					break;
				case HEAPTUPLE_DELETE_IN_PROGRESS:
					/* This is an expected case during concurrent vacuum */
					break;
				default:
					elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
					break;
			}

			if (tupgone)
			{
				lazy_record_dead_tuple(vacrelstats, &(tuple.t_self));
				tups_vacuumed += 1;
			}
			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,
									  InvalidBuffer, false))
					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);
			/* no XLOG for temp tables, though */
			if (!onerel->rd_istemp)
			{
				XLogRecPtr	recptr;

				recptr = log_heap_freeze(onerel, buf, FreezeLimit,
										 frozen, nfrozen);
				PageSetLSN(page, recptr);
			}
		}

		/*
		 * 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 */
			vacrelstats->num_dead_tuples = 0;
			vacuumed_pages++;
		}

		/*
		 * 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)
		{
			lazy_record_free_space(vacrelstats, blkno,
								   PageGetHeapFreeSpace(page));
		}

		/* Remember the location of the last page with nonremovable tuples */
		if (hastup)
			vacrelstats->nonempty_pages = blkno + 1;

		UnlockReleaseBuffer(buf);

		MIRROREDLOCK_BUFMGR_UNLOCK;
		/* -------- MirroredLock ---------- */

	}

	/* save stats for use later */
	vacrelstats->rel_tuples = num_tuples;
	vacrelstats->tuples_deleted = tups_vacuumed;

	/* 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)
	{
		/* Remove index entries */
		for (i = 0; i < nindexes; i++)
			lazy_vacuum_index(Irel[i], &indstats[i], vacrelstats);

		reindex_count++;

		/* 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, updated_stats);

	/* 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 pages",
					RelationGetRelationName(onerel),
					tups_vacuumed, num_tuples, nblocks),
			 errdetail("%.0f dead row versions cannot be removed yet.\n"
					   "There were %.0f unused item pointers.\n"
					   "%u pages contain useful free space.\n"
					   "%u pages are entirely empty.\n"
					   "%s.",
					   nkeep,
					   nunused,
					   vacrelstats->tot_free_pages,
					   empty_pages,
					   pg_rusage_show(&ru0))));
}
/*
 *	_hash_squeezebucket(rel, bucket)
 *
 *	Try to squeeze the tuples onto pages occurring earlier in the
 *	bucket chain in an attempt to free overflow pages. When we start
 *	the "squeezing", the page from which we start taking tuples (the
 *	"read" page) is the last bucket in the bucket chain and the page
 *	onto which we start squeezing tuples (the "write" page) is the
 *	first page in the bucket chain.  The read page works backward and
 *	the write page works forward; the procedure terminates when the
 *	read page and write page are the same page.
 *
 *	At completion of this procedure, it is guaranteed that all pages in
 *	the bucket are nonempty, unless the bucket is totally empty (in
 *	which case all overflow pages will be freed).  The original implementation
 *	required that to be true on entry as well, but it's a lot easier for
 *	callers to leave empty overflow pages and let this guy clean it up.
 *
 *	Caller must hold exclusive lock on the target bucket.  This allows
 *	us to safely lock multiple pages in the bucket.
 *
 *	Since this function is invoked in VACUUM, we provide an access strategy
 *	parameter that controls fetches of the bucket pages.
 */
void
_hash_squeezebucket(Relation rel,
                    Bucket bucket,
                    BlockNumber bucket_blkno,
                    BufferAccessStrategy bstrategy)
{
    BlockNumber wblkno;
    BlockNumber rblkno;
    Buffer		wbuf;
    Buffer		rbuf;
    Page		wpage;
    Page		rpage;
    HashPageOpaque wopaque;
    HashPageOpaque ropaque;
    bool		wbuf_dirty;

    /*
     * start squeezing into the base bucket page.
     */
    wblkno = bucket_blkno;
    wbuf = _hash_getbuf_with_strategy(rel,
                                      wblkno,
                                      HASH_WRITE,
                                      LH_BUCKET_PAGE,
                                      bstrategy);
    wpage = BufferGetPage(wbuf);
    wopaque = (HashPageOpaque) PageGetSpecialPointer(wpage);

    /*
     * if there aren't any overflow pages, there's nothing to squeeze.
     */
    if (!BlockNumberIsValid(wopaque->hasho_nextblkno))
    {
        _hash_relbuf(rel, wbuf);
        return;
    }

    /*
     * Find the last page in the bucket chain by starting at the base bucket
     * page and working forward.  Note: we assume that a hash bucket chain is
     * usually smaller than the buffer ring being used by VACUUM, else using
     * the access strategy here would be counterproductive.
     */
    rbuf = InvalidBuffer;
    ropaque = wopaque;
    do
    {
        rblkno = ropaque->hasho_nextblkno;
        if (rbuf != InvalidBuffer)
            _hash_relbuf(rel, rbuf);
        rbuf = _hash_getbuf_with_strategy(rel,
                                          rblkno,
                                          HASH_WRITE,
                                          LH_OVERFLOW_PAGE,
                                          bstrategy);
        rpage = BufferGetPage(rbuf);
        ropaque = (HashPageOpaque) PageGetSpecialPointer(rpage);
        Assert(ropaque->hasho_bucket == bucket);
    } while (BlockNumberIsValid(ropaque->hasho_nextblkno));

    /*
     * squeeze the tuples.
     */
    wbuf_dirty = false;
    for (;;)
    {
        OffsetNumber roffnum;
        OffsetNumber maxroffnum;
        OffsetNumber deletable[MaxOffsetNumber];
        int			ndeletable = 0;

        /* Scan each tuple in "read" page */
        maxroffnum = PageGetMaxOffsetNumber(rpage);
        for (roffnum = FirstOffsetNumber;
                roffnum <= maxroffnum;
                roffnum = OffsetNumberNext(roffnum))
        {
            IndexTuple	itup;
            Size		itemsz;

            itup = (IndexTuple) PageGetItem(rpage,
                                            PageGetItemId(rpage, roffnum));
            itemsz = IndexTupleDSize(*itup);
            itemsz = MAXALIGN(itemsz);

            /*
             * Walk up the bucket chain, looking for a page big enough for
             * this item.  Exit if we reach the read page.
             */
            while (PageGetFreeSpace(wpage) < itemsz)
            {
                Assert(!PageIsEmpty(wpage));

                wblkno = wopaque->hasho_nextblkno;
                Assert(BlockNumberIsValid(wblkno));

                if (wbuf_dirty)
                    _hash_wrtbuf(rel, wbuf);
                else
                    _hash_relbuf(rel, wbuf);

                /* nothing more to do if we reached the read page */
                if (rblkno == wblkno)
                {
                    if (ndeletable > 0)
                    {
                        /* Delete tuples we already moved off read page */
                        PageIndexMultiDelete(rpage, deletable, ndeletable);
                        _hash_wrtbuf(rel, rbuf);
                    }
                    else
                        _hash_relbuf(rel, rbuf);
                    return;
                }

                wbuf = _hash_getbuf_with_strategy(rel,
                                                  wblkno,
                                                  HASH_WRITE,
                                                  LH_OVERFLOW_PAGE,
                                                  bstrategy);
                wpage = BufferGetPage(wbuf);
                wopaque = (HashPageOpaque) PageGetSpecialPointer(wpage);
                Assert(wopaque->hasho_bucket == bucket);
                wbuf_dirty = false;
            }

            /*
             * we have found room so insert on the "write" page, being careful
             * to preserve hashkey ordering.  (If we insert many tuples into
             * the same "write" page it would be worth qsort'ing instead of
             * doing repeated _hash_pgaddtup.)
             */
            (void) _hash_pgaddtup(rel, wbuf, itemsz, itup);
            wbuf_dirty = true;

            /* remember tuple for deletion from "read" page */
            deletable[ndeletable++] = roffnum;
        }

        /*
         * If we reach here, there are no live tuples on the "read" page ---
         * it was empty when we got to it, or we moved them all.  So we can
         * just free the page without bothering with deleting tuples
         * individually.  Then advance to the previous "read" page.
         *
         * Tricky point here: if our read and write pages are adjacent in the
         * bucket chain, our write lock on wbuf will conflict with
         * _hash_freeovflpage's attempt to update the sibling links of the
         * removed page.  However, in that case we are done anyway, so we can
         * simply drop the write lock before calling _hash_freeovflpage.
         */
        rblkno = ropaque->hasho_prevblkno;
        Assert(BlockNumberIsValid(rblkno));

        /* are we freeing the page adjacent to wbuf? */
        if (rblkno == wblkno)
        {
            /* yes, so release wbuf lock first */
            if (wbuf_dirty)
                _hash_wrtbuf(rel, wbuf);
            else
                _hash_relbuf(rel, wbuf);
            /* free this overflow page (releases rbuf) */
            _hash_freeovflpage(rel, rbuf, bstrategy);
            /* done */
            return;
        }

        /* free this overflow page, then get the previous one */
        _hash_freeovflpage(rel, rbuf, bstrategy);

        rbuf = _hash_getbuf_with_strategy(rel,
                                          rblkno,
                                          HASH_WRITE,
                                          LH_OVERFLOW_PAGE,
                                          bstrategy);
        rpage = BufferGetPage(rbuf);
        ropaque = (HashPageOpaque) PageGetSpecialPointer(rpage);
        Assert(ropaque->hasho_bucket == bucket);
    }

    /* NOTREACHED */
}
static ArrayTuple
gistVacuumUpdate(GistVacuum *gv, BlockNumber blkno, bool needunion)
{
	ArrayTuple	res = {NULL, 0, false};
	Buffer		buffer;
	Page		page,
				tempPage = NULL;
	OffsetNumber i,
				maxoff;
	ItemId		iid;
	int			lenaddon = 4,
				curlenaddon = 0,
				nOffToDelete = 0,
				nBlkToDelete = 0;
	IndexTuple	idxtuple,
			   *addon = NULL;
	bool		needwrite = false;
	OffsetNumber offToDelete[MaxOffsetNumber];
	BlockNumber blkToDelete[MaxOffsetNumber];
	ItemPointerData *completed = NULL;
	int			ncompleted = 0,
				lencompleted = 16;

	vacuum_delay_point();

	buffer = ReadBufferWithStrategy(gv->index, blkno, gv->strategy);
	LockBuffer(buffer, GIST_EXCLUSIVE);
	gistcheckpage(gv->index, buffer);
	page = (Page) BufferGetPage(buffer);
	maxoff = PageGetMaxOffsetNumber(page);

	if (GistPageIsLeaf(page))
	{
		if (GistTuplesDeleted(page))
			needunion = needwrite = true;
	}
	else
	{
		completed = (ItemPointerData *) palloc(sizeof(ItemPointerData) * lencompleted);
		addon = (IndexTuple *) palloc(sizeof(IndexTuple) * lenaddon);

		/* get copy of page to work */
		tempPage = GistPageGetCopyPage(page);

		for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
		{
			ArrayTuple	chldtuple;
			bool		needchildunion;

			iid = PageGetItemId(tempPage, i);
			idxtuple = (IndexTuple) PageGetItem(tempPage, iid);
			needchildunion = (GistTupleIsInvalid(idxtuple)) ? true : false;

			if (needchildunion)
				elog(DEBUG2, "gistVacuumUpdate: need union for block %u",
					 ItemPointerGetBlockNumber(&(idxtuple->t_tid)));

			chldtuple = gistVacuumUpdate(gv, ItemPointerGetBlockNumber(&(idxtuple->t_tid)),
										 needchildunion);
			if (chldtuple.ituplen || chldtuple.emptypage)
			{
				/* update tuple or/and inserts new */
				if (chldtuple.emptypage)
					blkToDelete[nBlkToDelete++] = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
				offToDelete[nOffToDelete++] = i;
				PageIndexTupleDelete(tempPage, i);
				i--;
				maxoff--;
				needwrite = needunion = true;

				if (chldtuple.ituplen)
				{

					Assert(chldtuple.emptypage == false);
					while (curlenaddon + chldtuple.ituplen >= lenaddon)
					{
						lenaddon *= 2;
						addon = (IndexTuple *) repalloc(addon, sizeof(IndexTuple) * lenaddon);
					}

					memcpy(addon + curlenaddon, chldtuple.itup, chldtuple.ituplen * sizeof(IndexTuple));

					curlenaddon += chldtuple.ituplen;

					if (chldtuple.ituplen > 1)
					{
						/*
						 * child was split, so we need mark completion
						 * insert(split)
						 */
						int			j;

						while (ncompleted + chldtuple.ituplen > lencompleted)
						{
							lencompleted *= 2;
							completed = (ItemPointerData *) repalloc(completed, sizeof(ItemPointerData) * lencompleted);
						}
						for (j = 0; j < chldtuple.ituplen; j++)
						{
							ItemPointerCopy(&(chldtuple.itup[j]->t_tid), completed + ncompleted);
							ncompleted++;
						}
					}
					pfree(chldtuple.itup);
				}
			}
		}

		Assert(maxoff == PageGetMaxOffsetNumber(tempPage));

		if (curlenaddon)
		{
			/* insert updated tuples */
			if (gistnospace(tempPage, addon, curlenaddon, InvalidOffsetNumber, 0))
			{
				/* there is no space on page to insert tuples */
				res = vacuumSplitPage(gv, tempPage, buffer, addon, curlenaddon);
				tempPage = NULL;	/* vacuumSplitPage() free tempPage */
				needwrite = needunion = false;	/* gistSplit already forms
												 * unions and writes pages */
			}
			else
				/* enough free space */
				gistfillbuffer(gv->index, tempPage, addon, curlenaddon, InvalidOffsetNumber);
		}
	}

	/*
	 * If page is empty, we should remove pointer to it before deleting page
	 * (except root)
	 */

	if (blkno != GIST_ROOT_BLKNO && (PageIsEmpty(page) || (tempPage && PageIsEmpty(tempPage))))
	{
		/*
		 * New version of page is empty, so leave it unchanged, upper call
		 * will mark our page as deleted. In case of page split we never will
		 * be here...
		 *
		 * If page was empty it can't become non-empty during processing
		 */
		res.emptypage = true;
		UnlockReleaseBuffer(buffer);
	}
	else
	{
		/* write page and remove its childs if it need */

		START_CRIT_SECTION();

		if (tempPage && needwrite)
		{
			PageRestoreTempPage(tempPage, page);
			tempPage = NULL;
		}

		/* Empty index */
		if (PageIsEmpty(page) && blkno == GIST_ROOT_BLKNO)
		{
			needwrite = true;
			GistPageSetLeaf(page);
		}


		if (needwrite)
		{
			MarkBufferDirty(buffer);
			GistClearTuplesDeleted(page);

			if (!gv->index->rd_istemp)
			{
				XLogRecData *rdata;
				XLogRecPtr	recptr;
				char	   *xlinfo;

				rdata = formUpdateRdata(gv->index->rd_node, buffer,
										offToDelete, nOffToDelete,
										addon, curlenaddon, NULL);
				xlinfo = 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, XLogRecPtrForTemp);
		}

		END_CRIT_SECTION();

		if (needunion && !PageIsEmpty(page))
		{
			res.itup = (IndexTuple *) palloc(sizeof(IndexTuple));
			res.ituplen = 1;
			res.itup[0] = PageMakeUnionKey(gv, buffer);
		}

		UnlockReleaseBuffer(buffer);

		/* delete empty children, now we havn't any links to pointed subtrees */
		for (i = 0; i < nBlkToDelete; i++)
			gistDeleteSubtree(gv, blkToDelete[i]);

		if (ncompleted && !gv->index->rd_istemp)
			gistxlogInsertCompletion(gv->index->rd_node, completed, ncompleted);
	}


	for (i = 0; i < curlenaddon; i++)
		pfree(addon[i]);
	if (addon)
		pfree(addon);
	if (completed)
		pfree(completed);
	if (tempPage)
		pfree(tempPage);

	return res;
}
Exemple #29
0
/*
 *	lazy_scan_heap() -- scan an open heap relation
 *
 *		This routine sets commit status bits, builds lists of dead tuples
 *		and pages with free space, and calculates statistics on the number
 *		of live tuples in the heap.  When done, or when we run low on space
 *		for dead-tuple TIDs, invoke vacuuming of indexes and heap.
 *
 *		If there are no indexes then we just vacuum each dirty page as we
 *		process it, since there's no point in gathering many tuples.
 */
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.
	 */
	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;

		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();

		vacrelstats->scanned_pages++;

		/*
		 * 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)
		{
			/* 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++;
		}

		buf = ReadBufferExtended(onerel, MAIN_FORKNUM, blkno,
								 RBM_NORMAL, vac_strategy);

		/* We need buffer cleanup lock so that we can prune HOT chains. */
		LockBufferForCleanup(buf);

		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);

			if (!PageIsAllVisible(page))
			{
				PageSetAllVisible(page);
				SetBufferCommitInfoNeedsSave(buf);
			}

			LockBuffer(buf, BUFFER_LOCK_UNLOCK);

			/* Update the visibility map */
			if (!all_visible_according_to_vm)
			{
				visibilitymap_pin(onerel, blkno, &vmbuffer);
				LockBuffer(buf, BUFFER_LOCK_SHARE);
				if (PageIsAllVisible(page))
					visibilitymap_set(onerel, blkno, PageGetLSN(page), &vmbuffer);
				LockBuffer(buf, BUFFER_LOCK_UNLOCK);
			}

			ReleaseBuffer(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;
						}
					}
					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,
									  InvalidBuffer))
					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);

		/* Update the all-visible flag on the page */
		if (!PageIsAllVisible(page) && all_visible)
		{
			PageSetAllVisible(page);
			SetBufferCommitInfoNeedsSave(buf);
		}

		/*
		 * 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);
			SetBufferCommitInfoNeedsSave(buf);

			/*
			 * Normally, we would drop the lock on the heap page before
			 * updating the visibility map, but since this case shouldn't
			 * happen anyway, don't worry about that.
			 */
			visibilitymap_clear(onerel, blkno);
		}

		LockBuffer(buf, BUFFER_LOCK_UNLOCK);

		/* Update the visibility map */
		if (!all_visible_according_to_vm && all_visible)
		{
			visibilitymap_pin(onerel, blkno, &vmbuffer);
			LockBuffer(buf, BUFFER_LOCK_SHARE);
			if (PageIsAllVisible(page))
				visibilitymap_set(onerel, blkno, PageGetLSN(page), &vmbuffer);
			LockBuffer(buf, BUFFER_LOCK_UNLOCK);
		}

		ReleaseBuffer(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);

	/* 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++;
	}

	/* Release the pin on the visibility map page */
	if (BufferIsValid(vmbuffer))
	{
		ReleaseBuffer(vmbuffer);
		vmbuffer = InvalidBuffer;
	}

	/* 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))));
}
Exemple #30
0
/*
 *	_hash_squeezebucket(rel, bucket)
 *
 *	Try to squeeze the tuples onto pages occurring earlier in the
 *	bucket chain in an attempt to free overflow pages. When we start
 *	the "squeezing", the page from which we start taking tuples (the
 *	"read" page) is the last bucket in the bucket chain and the page
 *	onto which we start squeezing tuples (the "write" page) is the
 *	first page in the bucket chain.  The read page works backward and
 *	the write page works forward; the procedure terminates when the
 *	read page and write page are the same page.
 *
 *	At completion of this procedure, it is guaranteed that all pages in
 *	the bucket are nonempty, unless the bucket is totally empty (in
 *	which case all overflow pages will be freed).  The original implementation
 *	required that to be true on entry as well, but it's a lot easier for
 *	callers to leave empty overflow pages and let this guy clean it up.
 *
 *	Caller must hold exclusive lock on the target bucket.  This allows
 *	us to safely lock multiple pages in the bucket.
 */
void
_hash_squeezebucket(Relation rel,
					Bucket bucket,
					BlockNumber bucket_blkno)
{
	Buffer		wbuf;
	Buffer		rbuf = 0;
	BlockNumber wblkno;
	BlockNumber rblkno;
	Page		wpage;
	Page		rpage;
	HashPageOpaque wopaque;
	HashPageOpaque ropaque;
	OffsetNumber woffnum;
	OffsetNumber roffnum;
	IndexTuple	itup;
	Size		itemsz;

	/*
	 * start squeezing into the base bucket page.
	 */
	wblkno = bucket_blkno;
	wbuf = _hash_getbuf(rel, wblkno, HASH_WRITE);
	_hash_checkpage(rel, wbuf, LH_BUCKET_PAGE);
	wpage = BufferGetPage(wbuf);
	wopaque = (HashPageOpaque) PageGetSpecialPointer(wpage);

	/*
	 * if there aren't any overflow pages, there's nothing to squeeze.
	 */
	if (!BlockNumberIsValid(wopaque->hasho_nextblkno))
	{
		_hash_relbuf(rel, wbuf);
		return;
	}

	/*
	 * find the last page in the bucket chain by starting at the base bucket
	 * page and working forward.
	 */
	ropaque = wopaque;
	do
	{
		rblkno = ropaque->hasho_nextblkno;
		if (ropaque != wopaque)
			_hash_relbuf(rel, rbuf);
		rbuf = _hash_getbuf(rel, rblkno, HASH_WRITE);
		_hash_checkpage(rel, rbuf, LH_OVERFLOW_PAGE);
		rpage = BufferGetPage(rbuf);
		ropaque = (HashPageOpaque) PageGetSpecialPointer(rpage);
		Assert(ropaque->hasho_bucket == bucket);
	} while (BlockNumberIsValid(ropaque->hasho_nextblkno));

	/*
	 * squeeze the tuples.
	 */
	roffnum = FirstOffsetNumber;
	for (;;)
	{
		/* this test is needed in case page is empty on entry */
		if (roffnum <= PageGetMaxOffsetNumber(rpage))
		{
			itup = (IndexTuple) PageGetItem(rpage,
											PageGetItemId(rpage, roffnum));
			itemsz = IndexTupleDSize(*itup);
			itemsz = MAXALIGN(itemsz);

			/*
			 * Walk up the bucket chain, looking for a page big enough for
			 * this item.  Exit if we reach the read page.
			 */
			while (PageGetFreeSpace(wpage) < itemsz)
			{
				Assert(!PageIsEmpty(wpage));

				wblkno = wopaque->hasho_nextblkno;
				Assert(BlockNumberIsValid(wblkno));

				_hash_wrtbuf(rel, wbuf);

				if (rblkno == wblkno)
				{
					/* wbuf is already released */
					_hash_wrtbuf(rel, rbuf);
					return;
				}

				wbuf = _hash_getbuf(rel, wblkno, HASH_WRITE);
				_hash_checkpage(rel, wbuf, LH_OVERFLOW_PAGE);
				wpage = BufferGetPage(wbuf);
				wopaque = (HashPageOpaque) PageGetSpecialPointer(wpage);
				Assert(wopaque->hasho_bucket == bucket);
			}

			/*
			 * we have found room so insert on the "write" page.
			 */
			woffnum = OffsetNumberNext(PageGetMaxOffsetNumber(wpage));
			if (PageAddItem(wpage, (Item) itup, itemsz, woffnum, LP_USED)
				== InvalidOffsetNumber)
				elog(ERROR, "failed to add index item to \"%s\"",
					 RelationGetRelationName(rel));

			/*
			 * delete the tuple from the "read" page. PageIndexTupleDelete
			 * repacks the ItemId array, so 'roffnum' will be "advanced" to
			 * the "next" ItemId.
			 */
			PageIndexTupleDelete(rpage, roffnum);
		}

		/*
		 * if the "read" page is now empty because of the deletion (or because
		 * it was empty when we got to it), free it.
		 *
		 * Tricky point here: if our read and write pages are adjacent in the
		 * bucket chain, our write lock on wbuf will conflict with
		 * _hash_freeovflpage's attempt to update the sibling links of the
		 * removed page.  However, in that case we are done anyway, so we can
		 * simply drop the write lock before calling _hash_freeovflpage.
		 */
		if (PageIsEmpty(rpage))
		{
			rblkno = ropaque->hasho_prevblkno;
			Assert(BlockNumberIsValid(rblkno));

			/* are we freeing the page adjacent to wbuf? */
			if (rblkno == wblkno)
			{
				/* yes, so release wbuf lock first */
				_hash_wrtbuf(rel, wbuf);
				/* free this overflow page (releases rbuf) */
				_hash_freeovflpage(rel, rbuf);
				/* done */
				return;
			}

			/* free this overflow page, then get the previous one */
			_hash_freeovflpage(rel, rbuf);

			rbuf = _hash_getbuf(rel, rblkno, HASH_WRITE);
			_hash_checkpage(rel, rbuf, LH_OVERFLOW_PAGE);
			rpage = BufferGetPage(rbuf);
			ropaque = (HashPageOpaque) PageGetSpecialPointer(rpage);
			Assert(ropaque->hasho_bucket == bucket);

			roffnum = FirstOffsetNumber;
		}
	}

	/* NOTREACHED */
}