示例#1
0
/*
 *	visibilitymap_set - set a bit on a previously pinned page
 *
 * recptr is the LSN of the XLOG record we're replaying, if we're in recovery,
 * or InvalidXLogRecPtr in normal running.  The page LSN is advanced to the
 * one provided; in normal running, we generate a new XLOG record and set the
 * page LSN to that value.  cutoff_xid is the largest xmin on the page being
 * marked all-visible; it is needed for Hot Standby, and can be
 * InvalidTransactionId if the page contains no tuples.
 *
 * You must pass a buffer containing the correct map page to this function.
 * Call visibilitymap_pin first to pin the right one. This function doesn't do
 * any I/O.
 */
void
visibilitymap_set(Relation rel, BlockNumber heapBlk, XLogRecPtr recptr,
				  Buffer buf, TransactionId cutoff_xid)
{
	BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
	uint32		mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
	uint8		mapBit = HEAPBLK_TO_MAPBIT(heapBlk);
	Page		page;
	char	   *map;

#ifdef TRACE_VISIBILITYMAP
	elog(DEBUG1, "vm_set %s %d", RelationGetRelationName(rel), heapBlk);
#endif

	Assert(InRecovery || XLogRecPtrIsInvalid(recptr));

	/* Check that we have the right page pinned */
	if (!BufferIsValid(buf) || BufferGetBlockNumber(buf) != mapBlock)
		elog(ERROR, "wrong buffer passed to visibilitymap_set");

	page = BufferGetPage(buf);
	map = PageGetContents(page);
	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);

	if (!(map[mapByte] & (1 << mapBit)))
	{
		START_CRIT_SECTION();

		map[mapByte] |= (1 << mapBit);
		MarkBufferDirty(buf);

		if (RelationNeedsWAL(rel))
		{
			if (XLogRecPtrIsInvalid(recptr))
				recptr = log_heap_visible(rel->rd_node, heapBlk, buf,
										  cutoff_xid);
			PageSetLSN(page, recptr);
			PageSetTLI(page, ThisTimeLineID);
		}

		END_CRIT_SECTION();
	}

	LockBuffer(buf, BUFFER_LOCK_UNLOCK);
}
示例#2
0
static void
gistRedoCreateIndex(XLogReaderState *record)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	Buffer		buffer;
	Page		page;

	buffer = XLogInitBufferForRedo(record, 0);
	Assert(BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO);
	page = (Page) BufferGetPage(buffer);

	GISTInitBuffer(buffer, F_LEAF);

	PageSetLSN(page, lsn);

	MarkBufferDirty(buffer);
	UnlockReleaseBuffer(buffer);
}
示例#3
0
static void
ginRedoClearIncompleteSplit(XLogReaderState *record, uint8 block_id)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	Buffer		buffer;
	Page		page;

	if (XLogReadBufferForRedo(record, block_id, &buffer) == BLK_NEEDS_REDO)
	{
		page = (Page) BufferGetPage(buffer);
		GinPageGetOpaque(page)->flags &= ~GIN_INCOMPLETE_SPLIT;

		PageSetLSN(page, lsn);
		MarkBufferDirty(buffer);
	}
	if (BufferIsValid(buffer))
		UnlockReleaseBuffer(buffer);
}
示例#4
0
static void
_bt_restore_meta(XLogReaderState *record, uint8 block_id)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	Buffer		metabuf;
	Page		metapg;
	BTMetaPageData *md;
	BTPageOpaque pageop;
	xl_btree_metadata *xlrec;
	char	   *ptr;
	Size		len;

	metabuf = XLogInitBufferForRedo(record, block_id);
	ptr = XLogRecGetBlockData(record, block_id, &len);

	Assert(len == sizeof(xl_btree_metadata));
	Assert(BufferGetBlockNumber(metabuf) == BTREE_METAPAGE);
	xlrec = (xl_btree_metadata *) ptr;
	metapg = BufferGetPage(metabuf);

	_bt_pageinit(metapg, BufferGetPageSize(metabuf));

	md = BTPageGetMeta(metapg);
	md->btm_magic = BTREE_MAGIC;
	md->btm_version = BTREE_VERSION;
	md->btm_root = xlrec->root;
	md->btm_level = xlrec->level;
	md->btm_fastroot = xlrec->fastroot;
	md->btm_fastlevel = xlrec->fastlevel;

	pageop = (BTPageOpaque) PageGetSpecialPointer(metapg);
	pageop->btpo_flags = BTP_META;

	/*
	 * Set pd_lower just past the end of the metadata.  This is not essential
	 * but it makes the page look compressible to xlog.c.
	 */
	((PageHeader) metapg)->pd_lower =
		((char *) md + sizeof(BTMetaPageData)) - (char *) metapg;

	PageSetLSN(metapg, lsn);
	MarkBufferDirty(metabuf);
	UnlockReleaseBuffer(metabuf);
}
示例#5
0
文件: gistxlog.c 项目: GisKook/Gis
static void
gistRedoCreateIndex(XLogRecPtr lsn, XLogRecord *record)
{
	RelFileNode *node = (RelFileNode *) XLogRecGetData(record);
	Buffer		buffer;
	Page		page;

	buffer = XLogReadBuffer(*node, GIST_ROOT_BLKNO, true);
	Assert(BufferIsValid(buffer));
	page = (Page) BufferGetPage(buffer);

	GISTInitBuffer(buffer, F_LEAF);

	PageSetLSN(page, lsn);
	PageSetTLI(page, ThisTimeLineID);

	MarkBufferDirty(buffer);
	UnlockReleaseBuffer(buffer);
}
示例#6
0
文件: gist.c 项目: Hu1-Li/postgres
/*
 *	gistbuildempty() -- build an empty gist index in the initialization fork
 */
void
gistbuildempty(Relation index)
{
	Buffer		buffer;

	/* Initialize the root page */
	buffer = ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
	LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);

	/* Initialize and xlog buffer */
	START_CRIT_SECTION();
	GISTInitBuffer(buffer, F_LEAF);
	MarkBufferDirty(buffer);
	log_newpage_buffer(buffer, true);
	END_CRIT_SECTION();

	/* Unlock and release the buffer */
	UnlockReleaseBuffer(buffer);
}
示例#7
0
/*
 * Write the given statistics to the index's metapage
 *
 * Note: nPendingPages and ginVersion are *not* copied over
 */
void
ginUpdateStats(Relation index, const GinStatsData *stats)
{
	Buffer		metabuffer;
	Page		metapage;
	GinMetaPageData *metadata;

	metabuffer = ReadBuffer(index, GIN_METAPAGE_BLKNO);
	LockBuffer(metabuffer, GIN_EXCLUSIVE);
	metapage = BufferGetPage(metabuffer);
	metadata = GinPageGetMeta(metapage);

	START_CRIT_SECTION();

	metadata->nTotalPages = stats->nTotalPages;
	metadata->nEntryPages = stats->nEntryPages;
	metadata->nDataPages = stats->nDataPages;
	metadata->nEntries = stats->nEntries;

	MarkBufferDirty(metabuffer);

	if (RelationNeedsWAL(index))
	{
		XLogRecPtr	recptr;
		ginxlogUpdateMeta data;

		data.node = index->rd_node;
		data.ntuples = 0;
		data.newRightlink = data.prevTail = InvalidBlockNumber;
		memcpy(&data.metadata, metadata, sizeof(GinMetaPageData));

		XLogBeginInsert();
		XLogRegisterData((char *) &data, sizeof(ginxlogUpdateMeta));
		XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT);

		recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_UPDATE_META_PAGE);
		PageSetLSN(metapage, recptr);
	}

	UnlockReleaseBuffer(metabuffer);

	END_CRIT_SECTION();
}
示例#8
0
/*
 * _bt_clear_incomplete_split -- clear INCOMPLETE_SPLIT flag on a page
 *
 * This is a common subroutine of the redo functions of all the WAL record
 * types that can insert a downlink: insert, split, and newroot.
 */
static void
_bt_clear_incomplete_split(XLogReaderState *record, uint8 block_id)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	Buffer		buf;

	if (XLogReadBufferForRedo(record, block_id, &buf) == BLK_NEEDS_REDO)
	{
		Page		page = (Page) BufferGetPage(buf);
		BTPageOpaque pageop = (BTPageOpaque) PageGetSpecialPointer(page);

		Assert((pageop->btpo_flags & BTP_INCOMPLETE_SPLIT) != 0);
		pageop->btpo_flags &= ~BTP_INCOMPLETE_SPLIT;

		PageSetLSN(page, lsn);
		MarkBufferDirty(buf);
	}
	if (BufferIsValid(buf))
		UnlockReleaseBuffer(buf);
}
示例#9
0
/*
 * replay a hash index meta page
 */
static void
hash_xlog_init_meta_page(XLogReaderState *record)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	Page		page;
	Buffer		metabuf;

	xl_hash_init_meta_page *xlrec = (xl_hash_init_meta_page *) XLogRecGetData(record);

	/* create the index' metapage */
	metabuf = XLogInitBufferForRedo(record, 0);
	Assert(BufferIsValid(metabuf));
	_hash_init_metabuffer(metabuf, xlrec->num_tuples, xlrec->procid,
						  xlrec->ffactor, true);
	page = (Page) BufferGetPage(metabuf);
	PageSetLSN(page, lsn);
	MarkBufferDirty(metabuf);
	/* all done */
	UnlockReleaseBuffer(metabuf);
}
示例#10
0
void
brinbuildempty(Relation index)
{
	Buffer		metabuf;

	/* An empty BRIN index has a metapage only. */
	metabuf =
		ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
	LockBuffer(metabuf, BUFFER_LOCK_EXCLUSIVE);

	/* Initialize and xlog metabuffer. */
	START_CRIT_SECTION();
	brin_metapage_init(BufferGetPage(metabuf), BrinGetPagesPerRange(index),
					   BRIN_CURRENT_VERSION);
	MarkBufferDirty(metabuf);
	log_newpage_buffer(metabuf, false);
	END_CRIT_SECTION();

	UnlockReleaseBuffer(metabuf);
}
示例#11
0
static void
ginRedoClearIncompleteSplit(XLogRecPtr lsn, RelFileNode node, BlockNumber blkno)
{
    Buffer		buffer;
    Page		page;

    buffer = XLogReadBuffer(node, blkno, false);
    if (!BufferIsValid(buffer))
        return;					/* page was deleted, nothing to do */
    page = (Page) BufferGetPage(buffer);

    if (lsn > PageGetLSN(page))
    {
        GinPageGetOpaque(page)->flags &= ~GIN_INCOMPLETE_SPLIT;

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

    UnlockReleaseBuffer(buffer);
}
示例#12
0
/*
 * replay split cleanup flag operation for primary bucket page.
 */
static void
hash_xlog_split_cleanup(XLogReaderState *record)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	Buffer		buffer;
	Page		page;

	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
	{
		HashPageOpaque bucket_opaque;

		page = (Page) BufferGetPage(buffer);

		bucket_opaque = (HashPageOpaque) PageGetSpecialPointer(page);
		bucket_opaque->hasho_flag &= ~LH_BUCKET_NEEDS_SPLIT_CLEANUP;
		PageSetLSN(page, lsn);
		MarkBufferDirty(buffer);
	}
	if (BufferIsValid(buffer))
		UnlockReleaseBuffer(buffer);
}
示例#13
0
static void
gistRedoCreateIndex(XLogRecPtr lsn, XLogRecord *record)
{
	RelFileNode *node = (RelFileNode *) XLogRecGetData(record);
	Buffer		buffer;
	Page		page;

	/* Backup blocks are not used in create_index records */
	Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));

	buffer = XLogReadBuffer(*node, GIST_ROOT_BLKNO, true);
	Assert(BufferIsValid(buffer));
	page = (Page) BufferGetPage(buffer);

	GISTInitBuffer(buffer, F_LEAF);

	PageSetLSN(page, lsn);

	MarkBufferDirty(buffer);
	UnlockReleaseBuffer(buffer);
}
示例#14
0
static void
btree_xlog_newroot(XLogReaderState *record)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	xl_btree_newroot *xlrec = (xl_btree_newroot *) XLogRecGetData(record);
	Buffer		buffer;
	Page		page;
	BTPageOpaque pageop;
	char	   *ptr;
	Size		len;

	buffer = XLogInitBufferForRedo(record, 0);
	page = (Page) BufferGetPage(buffer);

	_bt_pageinit(page, BufferGetPageSize(buffer));
	pageop = (BTPageOpaque) PageGetSpecialPointer(page);

	pageop->btpo_flags = BTP_ROOT;
	pageop->btpo_prev = pageop->btpo_next = P_NONE;
	pageop->btpo.level = xlrec->level;
	if (xlrec->level == 0)
		pageop->btpo_flags |= BTP_LEAF;
	pageop->btpo_cycleid = 0;

	if (xlrec->level > 0)
	{
		ptr = XLogRecGetBlockData(record, 0, &len);
		_bt_restore_page(page, ptr, len);

		/* Clear the incomplete-split flag in left child */
		_bt_clear_incomplete_split(record, 1);
	}

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

	_bt_restore_meta(record, 2);
}
示例#15
0
/*
 * replay for update meta page
 */
static void
hash_xlog_update_meta_page(XLogReaderState *record)
{
	HashMetaPage metap;
	XLogRecPtr	lsn = record->EndRecPtr;
	xl_hash_update_meta_page *xldata = (xl_hash_update_meta_page *) XLogRecGetData(record);
	Buffer		metabuf;
	Page		page;

	if (XLogReadBufferForRedo(record, 0, &metabuf) == BLK_NEEDS_REDO)
	{
		page = BufferGetPage(metabuf);
		metap = HashPageGetMeta(page);

		metap->hashm_ntuples = xldata->ntuples;

		PageSetLSN(page, lsn);
		MarkBufferDirty(metabuf);
	}
	if (BufferIsValid(metabuf))
		UnlockReleaseBuffer(metabuf);
}
示例#16
0
文件: gist.c 项目: AlexHill/postgres
/*
 *	gistbuildempty() -- build an empty gist index in the initialization fork
 */
Datum
gistbuildempty(PG_FUNCTION_ARGS)
{
	Relation	index = (Relation) PG_GETARG_POINTER(0);
	Buffer		buffer;

	/* Initialize the root page */
	buffer = ReadBufferExtended(index, INIT_FORKNUM, P_NEW, RBM_NORMAL, NULL);
	LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);

	/* Initialize and xlog buffer */
	START_CRIT_SECTION();
	GISTInitBuffer(buffer, F_LEAF);
	MarkBufferDirty(buffer);
	log_newpage_buffer(buffer, true);
	END_CRIT_SECTION();

	/* Unlock and release the buffer */
	UnlockReleaseBuffer(buffer);

	PG_RETURN_VOID();
}
示例#17
0
/*
 * This is functionally the same as heap_xlog_newpage.
 */
static void
ginRedoVacuumPage(XLogRecPtr lsn, XLogRecord *record)
{
    ginxlogVacuumPage *xlrec = (ginxlogVacuumPage *) XLogRecGetData(record);
    char	   *blk = ((char *) xlrec) + sizeof(ginxlogVacuumPage);
    Buffer		buffer;
    Page		page;

    Assert(xlrec->hole_offset < BLCKSZ);
    Assert(xlrec->hole_length < BLCKSZ);

    /* Backup blocks are not used, we'll re-initialize the page always. */
    Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));

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

    if (xlrec->hole_length == 0)
    {
        memcpy((char *) page, blk, BLCKSZ);
    }
    else
    {
        memcpy((char *) page, blk, xlrec->hole_offset);
        /* must zero-fill the hole */
        MemSet((char *) page + xlrec->hole_offset, 0, xlrec->hole_length);
        memcpy((char *) page + (xlrec->hole_offset + xlrec->hole_length),
               blk + xlrec->hole_offset,
               BLCKSZ - (xlrec->hole_offset + xlrec->hole_length));
    }

    PageSetLSN(page, lsn);

    MarkBufferDirty(buffer);
    UnlockReleaseBuffer(buffer);
}
示例#18
0
文件: gistxlog.c 项目: GisKook/Gis
static void
gistRedoPageDeleteRecord(XLogRecPtr lsn, XLogRecord *record)
{
	gistxlogPageDelete *xldata = (gistxlogPageDelete *) XLogRecGetData(record);
	Buffer		buffer;
	Page		page;

	/* nothing else 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);
	GistPageSetDeleted(page);

	PageSetLSN(page, lsn);
	PageSetTLI(page, ThisTimeLineID);
	MarkBufferDirty(buffer);
	UnlockReleaseBuffer(buffer);
}
示例#19
0
/*
 * Initialize a page as an empty regular BRIN page, WAL-log this, and record
 * the page in FSM.
 *
 * There are several corner situations in which we extend the relation to
 * obtain a new page and later find that we cannot use it immediately.  When
 * that happens, we don't want to leave the page go unrecorded in FSM, because
 * there is no mechanism to get the space back and the index would bloat.
 * Also, because we would not WAL-log the action that would initialize the
 * page, the page would go uninitialized in a standby (or after recovery).
 */
static void
brin_initialize_empty_new_buffer(Relation idxrel, Buffer buffer)
{
	Page		page;

	BRIN_elog((DEBUG2,
			   "brin_initialize_empty_new_buffer: initializing blank page %u",
			   BufferGetBlockNumber(buffer)));

	START_CRIT_SECTION();
	page = BufferGetPage(buffer);
	brin_page_init(page, BRIN_PAGETYPE_REGULAR);
	MarkBufferDirty(buffer);
	log_newpage_buffer(buffer, true);
	END_CRIT_SECTION();

	/*
	 * We update the FSM for this page, but this is not WAL-logged.  This is
	 * acceptable because VACUUM will scan the index and update the FSM with
	 * pages whose FSM records were forgotten in a crash.
	 */
	RecordPageWithFreeSpace(idxrel, BufferGetBlockNumber(buffer),
							br_page_get_freespace(page));
}
示例#20
0
static void
ginRedoVacuumDataLeafPage(XLogReaderState *record)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	Buffer		buffer;

	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
	{
		Page		page = BufferGetPage(buffer);
		Size		len;
		ginxlogVacuumDataLeafPage *xlrec;

		xlrec = (ginxlogVacuumDataLeafPage *) XLogRecGetBlockData(record, 0, &len);

		Assert(GinPageIsLeaf(page));
		Assert(GinPageIsData(page));

		ginRedoRecompress(page, &xlrec->data);
		PageSetLSN(page, lsn);
		MarkBufferDirty(buffer);
	}
	if (BufferIsValid(buffer))
		UnlockReleaseBuffer(buffer);
}
示例#21
0
文件: vacuumlazy.c 项目: hl0103/pgxc
/*
 *	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))));
}
示例#22
0
文件: gininsert.c 项目: Brar/postgres
IndexBuildResult *
ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
{
	IndexBuildResult *result;
	double		reltuples;
	GinBuildState buildstate;
	Buffer		RootBuffer,
				MetaBuffer;
	ItemPointerData *list;
	Datum		key;
	GinNullCategory category;
	uint32		nlist;
	MemoryContext oldCtx;
	OffsetNumber attnum;

	if (RelationGetNumberOfBlocks(index) != 0)
		elog(ERROR, "index \"%s\" already contains data",
			 RelationGetRelationName(index));

	initGinState(&buildstate.ginstate, index);
	buildstate.indtuples = 0;
	memset(&buildstate.buildStats, 0, sizeof(GinStatsData));

	/* initialize the meta page */
	MetaBuffer = GinNewBuffer(index);

	/* initialize the root page */
	RootBuffer = GinNewBuffer(index);

	START_CRIT_SECTION();
	GinInitMetabuffer(MetaBuffer);
	MarkBufferDirty(MetaBuffer);
	GinInitBuffer(RootBuffer, GIN_LEAF);
	MarkBufferDirty(RootBuffer);

	if (RelationNeedsWAL(index))
	{
		XLogRecPtr	recptr;
		Page		page;

		XLogBeginInsert();
		XLogRegisterBuffer(0, MetaBuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
		XLogRegisterBuffer(1, RootBuffer, REGBUF_WILL_INIT);

		recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_CREATE_INDEX);

		page = BufferGetPage(RootBuffer);
		PageSetLSN(page, recptr);

		page = BufferGetPage(MetaBuffer);
		PageSetLSN(page, recptr);
	}

	UnlockReleaseBuffer(MetaBuffer);
	UnlockReleaseBuffer(RootBuffer);
	END_CRIT_SECTION();

	/* count the root as first entry page */
	buildstate.buildStats.nEntryPages++;

	/*
	 * create a temporary memory context that is used to hold data not yet
	 * dumped out to the index
	 */
	buildstate.tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
											  "Gin build temporary context",
											  ALLOCSET_DEFAULT_SIZES);

	/*
	 * create a temporary memory context that is used for calling
	 * ginExtractEntries(), and can be reset after each tuple
	 */
	buildstate.funcCtx = AllocSetContextCreate(CurrentMemoryContext,
											   "Gin build temporary context for user-defined function",
											   ALLOCSET_DEFAULT_SIZES);

	buildstate.accum.ginstate = &buildstate.ginstate;
	ginInitBA(&buildstate.accum);

	/*
	 * Do the heap scan.  We disallow sync scan here because dataPlaceToPage
	 * prefers to receive tuples in TID order.
	 */
	reltuples = IndexBuildHeapScan(heap, index, indexInfo, false,
								   ginBuildCallback, (void *) &buildstate, NULL);

	/* dump remaining entries to the index */
	oldCtx = MemoryContextSwitchTo(buildstate.tmpCtx);
	ginBeginBAScan(&buildstate.accum);
	while ((list = ginGetBAEntry(&buildstate.accum,
								 &attnum, &key, &category, &nlist)) != NULL)
	{
		/* there could be many entries, so be willing to abort here */
		CHECK_FOR_INTERRUPTS();
		ginEntryInsert(&buildstate.ginstate, attnum, key, category,
					   list, nlist, &buildstate.buildStats);
	}
	MemoryContextSwitchTo(oldCtx);

	MemoryContextDelete(buildstate.funcCtx);
	MemoryContextDelete(buildstate.tmpCtx);

	/*
	 * Update metapage stats
	 */
	buildstate.buildStats.nTotalPages = RelationGetNumberOfBlocks(index);
	ginUpdateStats(index, &buildstate.buildStats);

	/*
	 * Return statistics
	 */
	result = (IndexBuildResult *) palloc(sizeof(IndexBuildResult));

	result->heap_tuples = reltuples;
	result->index_tuples = buildstate.indtuples;

	return result;
}
示例#23
0
/*
 * Main entry point to GiST index build. Initially calls insert over and over,
 * but switches to more efficient buffering build algorithm after a certain
 * number of tuples (unless buffering mode is disabled).
 */
Datum
gistbuild(PG_FUNCTION_ARGS)
{
	Relation	heap = (Relation) PG_GETARG_POINTER(0);
	Relation	index = (Relation) PG_GETARG_POINTER(1);
	IndexInfo  *indexInfo = (IndexInfo *) PG_GETARG_POINTER(2);
	IndexBuildResult *result;
	double		reltuples;
	GISTBuildState buildstate;
	Buffer		buffer;
	Page		page;
	MemoryContext oldcxt = CurrentMemoryContext;
	int			fillfactor;

	buildstate.indexrel = index;
	if (index->rd_options)
	{
		/* Get buffering mode from the options string */
		GiSTOptions *options = (GiSTOptions *) index->rd_options;
		char	   *bufferingMode = (char *) options + options->bufferingModeOffset;

		if (strcmp(bufferingMode, "on") == 0)
			buildstate.bufferingMode = GIST_BUFFERING_STATS;
		else if (strcmp(bufferingMode, "off") == 0)
			buildstate.bufferingMode = GIST_BUFFERING_DISABLED;
		else
			buildstate.bufferingMode = GIST_BUFFERING_AUTO;

		fillfactor = options->fillfactor;
	}
	else
	{
		/*
		 * By default, switch to buffering mode when the index grows too large
		 * to fit in cache.
		 */
		buildstate.bufferingMode = GIST_BUFFERING_AUTO;
		fillfactor = GIST_DEFAULT_FILLFACTOR;
	}
	/* Calculate target amount of free space to leave on pages */
	buildstate.freespace = BLCKSZ * (100 - fillfactor) / 100;

	/*
	 * We expect to be called exactly once for any index relation. If that's
	 * not the case, big trouble's what we have.
	 */
	if (RelationGetNumberOfBlocks(index) != 0)
		elog(ERROR, "index \"%s\" already contains data",
			 RelationGetRelationName(index));

	/* no locking is needed */
	buildstate.giststate = initGISTstate(index);

	/*
	 * Create a temporary memory context that is reset once for each tuple
	 * processed.  (Note: we don't bother to make this a child of the
	 * giststate's scanCxt, so we have to delete it separately at the end.)
	 */
	buildstate.giststate->tempCxt = createTempGistContext();

	/* initialize the root page */
	buffer = gistNewBuffer(index);
	Assert(BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO);
	page = BufferGetPage(buffer);

	START_CRIT_SECTION();

	GISTInitBuffer(buffer, F_LEAF);

	MarkBufferDirty(buffer);

	if (RelationNeedsWAL(index))
	{
		XLogRecPtr	recptr;
		XLogRecData rdata;

		rdata.data = (char *) &(index->rd_node);
		rdata.len = sizeof(RelFileNode);
		rdata.buffer = InvalidBuffer;
		rdata.next = NULL;

		recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_CREATE_INDEX, &rdata);
		PageSetLSN(page, recptr);
		PageSetTLI(page, ThisTimeLineID);
	}
	else
		PageSetLSN(page, gistGetFakeLSN(heap));

	UnlockReleaseBuffer(buffer);

	END_CRIT_SECTION();

	/* build the index */
	buildstate.indtuples = 0;
	buildstate.indtuplesSize = 0;

	/*
	 * Do the heap scan.
	 */
	reltuples = IndexBuildHeapScan(heap, index, indexInfo, true,
								   gistBuildCallback, (void *) &buildstate);

	/*
	 * If buffering was used, flush out all the tuples that are still in the
	 * buffers.
	 */
	if (buildstate.bufferingMode == GIST_BUFFERING_ACTIVE)
	{
		elog(DEBUG1, "all tuples processed, emptying buffers");
		gistEmptyAllBuffers(&buildstate);
		gistFreeBuildBuffers(buildstate.gfbb);
	}

	/* okay, all heap tuples are indexed */
	MemoryContextSwitchTo(oldcxt);
	MemoryContextDelete(buildstate.giststate->tempCxt);

	freeGISTstate(buildstate.giststate);

	/*
	 * Return statistics
	 */
	result = (IndexBuildResult *) palloc(sizeof(IndexBuildResult));

	result->heap_tuples = reltuples;
	result->index_tuples = (double) buildstate.indtuples;

	PG_RETURN_POINTER(result);
}
示例#24
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);
}
示例#25
0
static void
gistRedoPageSplitRecord(XLogReaderState *record)
{
	XLogRecPtr	lsn = record->EndRecPtr;
	gistxlogPageSplit *xldata = (gistxlogPageSplit *) XLogRecGetData(record);
	Buffer		firstbuffer = InvalidBuffer;
	Buffer		buffer;
	Page		page;
	int			i;
	bool		isrootsplit = false;

	/*
	 * We must hold lock on the first-listed page throughout the action,
	 * including while updating the left child page (if any).  We can unlock
	 * remaining pages in the list as soon as they've been written, because
	 * there is no path for concurrent queries to reach those pages without
	 * first visiting the first-listed page.
	 */

	/* loop around all pages */
	for (i = 0; i < xldata->npage; i++)
	{
		int			flags;
		char	   *data;
		Size		datalen;
		int			num;
		BlockNumber blkno;
		IndexTuple *tuples;

		XLogRecGetBlockTag(record, i + 1, NULL, NULL, &blkno);
		if (blkno == GIST_ROOT_BLKNO)
		{
			Assert(i == 0);
			isrootsplit = true;
		}

		buffer = XLogInitBufferForRedo(record, i + 1);
		page = (Page) BufferGetPage(buffer);
		data = XLogRecGetBlockData(record, i + 1, &datalen);

		tuples = decodePageSplitRecord(data, datalen, &num);

		/* ok, clear buffer */
		if (xldata->origleaf && blkno != GIST_ROOT_BLKNO)
			flags = F_LEAF;
		else
			flags = 0;
		GISTInitBuffer(buffer, flags);

		/* and fill it */
		gistfillbuffer(page, tuples, num, FirstOffsetNumber);

		if (blkno == GIST_ROOT_BLKNO)
		{
			GistPageGetOpaque(page)->rightlink = InvalidBlockNumber;
			GistPageSetNSN(page, xldata->orignsn);
			GistClearFollowRight(page);
		}
		else
		{
			if (i < xldata->npage - 1)
			{
				BlockNumber nextblkno;

				XLogRecGetBlockTag(record, i + 2, NULL, NULL, &nextblkno);
				GistPageGetOpaque(page)->rightlink = nextblkno;
			}
			else
				GistPageGetOpaque(page)->rightlink = xldata->origrlink;
			GistPageSetNSN(page, xldata->orignsn);
			if (i < xldata->npage - 1 && !isrootsplit &&
				xldata->markfollowright)
				GistMarkFollowRight(page);
			else
				GistClearFollowRight(page);
		}

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

		if (i == 0)
			firstbuffer = buffer;
		else
			UnlockReleaseBuffer(buffer);
	}

	/* Fix follow-right data on left child page, if any */
	if (XLogRecHasBlockRef(record, 0))
		gistRedoClearFollowRight(record, 0);

	/* Finally, release lock on the first page */
	UnlockReleaseBuffer(firstbuffer);
}
示例#26
0
/*
 *	visibilitymap_truncate - truncate the visibility map
 *
 * The caller must hold AccessExclusiveLock on the relation, to ensure that
 * other backends receive the smgr invalidation event that this function sends
 * before they access the VM again.
 *
 * nheapblocks is the new size of the heap.
 */
void
visibilitymap_truncate(Relation rel, BlockNumber nheapblocks)
{
	BlockNumber newnblocks;

	/* last remaining block, byte, and bit */
	BlockNumber truncBlock = HEAPBLK_TO_MAPBLOCK(nheapblocks);
	uint32		truncByte = HEAPBLK_TO_MAPBYTE(nheapblocks);
	uint8		truncBit = HEAPBLK_TO_MAPBIT(nheapblocks);

#ifdef TRACE_VISIBILITYMAP
	elog(DEBUG1, "vm_truncate %s %d", RelationGetRelationName(rel), nheapblocks);
#endif

	RelationOpenSmgr(rel);

	/*
	 * If no visibility map has been created yet for this relation, there's
	 * nothing to truncate.
	 */
	if (!smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
		return;

	/*
	 * Unless the new size is exactly at a visibility map page boundary, the
	 * tail bits in the last remaining map page, representing truncated heap
	 * blocks, need to be cleared. This is not only tidy, but also necessary
	 * because we don't get a chance to clear the bits if the heap is extended
	 * again.
	 */
	if (truncByte != 0 || truncBit != 0)
	{
		Buffer		mapBuffer;
		Page		page;
		char	   *map;

		newnblocks = truncBlock + 1;

		mapBuffer = vm_readbuf(rel, truncBlock, false);
		if (!BufferIsValid(mapBuffer))
		{
			/* nothing to do, the file was already smaller */
			return;
		}

		page = BufferGetPage(mapBuffer);
		map = PageGetContents(page);

		LockBuffer(mapBuffer, BUFFER_LOCK_EXCLUSIVE);

		/* Clear out the unwanted bytes. */
		MemSet(&map[truncByte + 1], 0, MAPSIZE - (truncByte + 1));

		/*
		 * Mask out the unwanted bits of the last remaining byte.
		 *
		 * ((1 << 0) - 1) = 00000000 ((1 << 1) - 1) = 00000001 ... ((1 << 6) -
		 * 1) = 00111111 ((1 << 7) - 1) = 01111111
		 */
		map[truncByte] &= (1 << truncBit) - 1;

		MarkBufferDirty(mapBuffer);
		UnlockReleaseBuffer(mapBuffer);
	}
	else
		newnblocks = truncBlock;

	if (smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM) <= newnblocks)
	{
		/* nothing to do, the file was already smaller than requested size */
		return;
	}

	/* Truncate the unused VM pages, and send smgr inval message */
	smgrtruncate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, newnblocks);

	/*
	 * We might as well update the local smgr_vm_nblocks setting. smgrtruncate
	 * sent an smgr cache inval message, which will cause other backends to
	 * invalidate their copy of smgr_vm_nblocks, and this one too at the next
	 * command boundary.  But this ensures it isn't outright wrong until then.
	 */
	if (rel->rd_smgr)
		rel->rd_smgr->smgr_vm_nblocks = newnblocks;
}
示例#27
0
文件: nbtpage.c 项目: 50wu/gpdb
/*
 *	_bt_getroot() -- Get the root page of the btree.
 *
 *		Since the root page can move around the btree file, we have to read
 *		its location from the metadata page, and then read the root page
 *		itself.  If no root page exists yet, we have to create one.  The
 *		standard class of race conditions exists here; I think I covered
 *		them all in the Hopi Indian rain dance of lock requests below.
 *
 *		The access type parameter (BT_READ or BT_WRITE) controls whether
 *		a new root page will be created or not.  If access = BT_READ,
 *		and no root page exists, we just return InvalidBuffer.	For
 *		BT_WRITE, we try to create the root page if it doesn't exist.
 *		NOTE that the returned root page will have only a read lock set
 *		on it even if access = BT_WRITE!
 *
 *		The returned page is not necessarily the true root --- it could be
 *		a "fast root" (a page that is alone in its level due to deletions).
 *		Also, if the root page is split while we are "in flight" to it,
 *		what we will return is the old root, which is now just the leftmost
 *		page on a probably-not-very-wide level.  For most purposes this is
 *		as good as or better than the true root, so we do not bother to
 *		insist on finding the true root.  We do, however, guarantee to
 *		return a live (not deleted or half-dead) page.
 *
 *		On successful return, the root page is pinned and read-locked.
 *		The metadata page is not locked or pinned on exit.
 */
Buffer
_bt_getroot(Relation rel, int access)
{
	Buffer		metabuf;
	Page		metapg;
	BTPageOpaque metaopaque;
	Buffer		rootbuf;
	Page		rootpage;
	BTPageOpaque rootopaque;
	BlockNumber rootblkno;
	uint32		rootlevel;
	BTMetaPageData *metad;

	MIRROREDLOCK_BUFMGR_MUST_ALREADY_BE_HELD;

	/*
	 * Try to use previously-cached metapage data to find the root.  This
	 * normally saves one buffer access per index search, which is a very
	 * helpful savings in bufmgr traffic and hence contention.
	 */
	if (rel->rd_amcache != NULL)
	{
		metad = (BTMetaPageData *) rel->rd_amcache;
		/* We shouldn't have cached it if any of these fail */
		Assert(metad->btm_magic == BTREE_MAGIC);
		Assert(metad->btm_version == BTREE_VERSION);
		Assert(metad->btm_root != P_NONE);

		rootblkno = metad->btm_fastroot;
		Assert(rootblkno != P_NONE);
		rootlevel = metad->btm_fastlevel;

		rootbuf = _bt_getbuf(rel, rootblkno, BT_READ);
		rootpage = BufferGetPage(rootbuf);
		rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);

		/*
		 * Since the cache might be stale, we check the page more carefully
		 * here than normal.  We *must* check that it's not deleted. If it's
		 * not alone on its level, then we reject too --- this may be overly
		 * paranoid but better safe than sorry.  Note we don't check P_ISROOT,
		 * because that's not set in a "fast root".
		 */
		if (!P_IGNORE(rootopaque) &&
			rootopaque->btpo.level == rootlevel &&
			P_LEFTMOST(rootopaque) &&
			P_RIGHTMOST(rootopaque))
		{
			/* OK, accept cached page as the root */
			return rootbuf;
		}
		_bt_relbuf(rel, rootbuf);
		/* Cache is stale, throw it away */
		if (rel->rd_amcache)
			pfree(rel->rd_amcache);
		rel->rd_amcache = NULL;
	}

	metabuf = _bt_getbuf(rel, BTREE_METAPAGE, BT_READ);
	metapg = BufferGetPage(metabuf);
	metaopaque = (BTPageOpaque) PageGetSpecialPointer(metapg);
	metad = BTPageGetMeta(metapg);

	/* sanity-check the metapage */
	if (!(metaopaque->btpo_flags & BTP_META) ||
		metad->btm_magic != BTREE_MAGIC)
		ereport(ERROR,
				(errcode(ERRCODE_INDEX_CORRUPTED),
				 errmsg("index \"%s\" is not a btree",
						RelationGetRelationName(rel))));

	if (metad->btm_version != BTREE_VERSION)
		ereport(ERROR,
				(errcode(ERRCODE_INDEX_CORRUPTED),
				 errmsg("version mismatch in index \"%s\": file version %d, code version %d",
						RelationGetRelationName(rel),
						metad->btm_version, BTREE_VERSION)));

	/* if no root page initialized yet, do it */
	if (metad->btm_root == P_NONE)
	{
		/* If access = BT_READ, caller doesn't want us to create root yet */
		if (access == BT_READ)
		{
			_bt_relbuf(rel, metabuf);
			return InvalidBuffer;
		}

		// Fetch gp_persistent_relation_node information that will be added to XLOG record.
		RelationFetchGpRelationNodeForXLog(rel);
		
		/* trade in our read lock for a write lock */
		LockBuffer(metabuf, BUFFER_LOCK_UNLOCK);
		LockBuffer(metabuf, BT_WRITE);

		/*
		 * Race condition:	if someone else initialized the metadata between
		 * the time we released the read lock and acquired the write lock, we
		 * must avoid doing it again.
		 */
		if (metad->btm_root != P_NONE)
		{
			/*
			 * Metadata initialized by someone else.  In order to guarantee no
			 * deadlocks, we have to release the metadata page and start all
			 * over again.	(Is that really true? But it's hardly worth trying
			 * to optimize this case.)
			 */
			_bt_relbuf(rel, metabuf);
			return _bt_getroot(rel, access);
		}

		/*
		 * Get, initialize, write, and leave a lock of the appropriate type on
		 * the new root page.  Since this is the first page in the tree, it's
		 * a leaf as well as the root.
		 */
		rootbuf = _bt_getbuf(rel, P_NEW, BT_WRITE);
		rootblkno = BufferGetBlockNumber(rootbuf);
		rootpage = BufferGetPage(rootbuf);
		rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);
		rootopaque->btpo_prev = rootopaque->btpo_next = P_NONE;
		rootopaque->btpo_flags = (BTP_LEAF | BTP_ROOT);
		rootopaque->btpo.level = 0;
		rootopaque->btpo_cycleid = 0;

		/* NO ELOG(ERROR) till meta is updated */
		START_CRIT_SECTION();

		metad->btm_root = rootblkno;
		metad->btm_level = 0;
		metad->btm_fastroot = rootblkno;
		metad->btm_fastlevel = 0;

		MarkBufferDirty(rootbuf);
		MarkBufferDirty(metabuf);

		/* XLOG stuff */
		if (!rel->rd_istemp)
		{
			xl_btree_newroot xlrec;
			XLogRecPtr	recptr;
			XLogRecData rdata;

			xl_btreenode_set(&(xlrec.btreenode), rel);
			xlrec.rootblk = rootblkno;
			xlrec.level = 0;

			rdata.data = (char *) &xlrec;
			rdata.len = SizeOfBtreeNewroot;
			rdata.buffer = InvalidBuffer;
			rdata.next = NULL;

			recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_NEWROOT, &rdata);

			PageSetLSN(rootpage, recptr);
			PageSetTLI(rootpage, ThisTimeLineID);
			PageSetLSN(metapg, recptr);
			PageSetTLI(metapg, ThisTimeLineID);
		}

		END_CRIT_SECTION();

		/*
		 * Send out relcache inval for metapage change (probably unnecessary
		 * here, but let's be safe).
		 */
		CacheInvalidateRelcache(rel);

		/*
		 * swap root write lock for read lock.	There is no danger of anyone
		 * else accessing the new root page while it's unlocked, since no one
		 * else knows where it is yet.
		 */
		LockBuffer(rootbuf, BUFFER_LOCK_UNLOCK);
		LockBuffer(rootbuf, BT_READ);

		/* okay, metadata is correct, release lock on it */
		_bt_relbuf(rel, metabuf);
	}
	else
	{
		rootblkno = metad->btm_fastroot;
		Assert(rootblkno != P_NONE);
		rootlevel = metad->btm_fastlevel;

		/*
		 * Cache the metapage data for next time
		 */
		rel->rd_amcache = MemoryContextAlloc(rel->rd_indexcxt,
											 sizeof(BTMetaPageData));
		memcpy(rel->rd_amcache, metad, sizeof(BTMetaPageData));

		/*
		 * We are done with the metapage; arrange to release it via first
		 * _bt_relandgetbuf call
		 */
		rootbuf = metabuf;

		for (;;)
		{
			rootbuf = _bt_relandgetbuf(rel, rootbuf, rootblkno, BT_READ);
			rootpage = BufferGetPage(rootbuf);
			rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);

			if (!P_IGNORE(rootopaque))
				break;

			/* it's dead, Jim.  step right one page */
			if (P_RIGHTMOST(rootopaque))
				elog(ERROR, "no live root page found in index \"%s\"",
					 RelationGetRelationName(rel));
			rootblkno = rootopaque->btpo_next;
		}

		/* Note: can't check btpo.level on deleted pages */
		if (rootopaque->btpo.level != rootlevel)
			elog(ERROR, "root page %u of index \"%s\" has level %u, expected %u",
				 rootblkno, RelationGetRelationName(rel),
				 rootopaque->btpo.level, rootlevel);
	}

	/*
	 * By here, we have a pin and read lock on the root page, and no lock set
	 * on the metadata page.  Return the root page's buffer.
	 */
	return rootbuf;
}
示例#28
0
文件: nbtpage.c 项目: 50wu/gpdb
/*
 * _bt_pagedel() -- Delete a page from the b-tree, if legal to do so.
 *
 * This action unlinks the page from the b-tree structure, removing all
 * pointers leading to it --- but not touching its own left and right links.
 * The page cannot be physically reclaimed right away, since other processes
 * may currently be trying to follow links leading to the page; they have to
 * be allowed to use its right-link to recover.  See nbtree/README.
 *
 * On entry, the target buffer must be pinned and locked (either read or write
 * lock is OK).  This lock and pin will be dropped before exiting.
 *
 * The "stack" argument can be a search stack leading (approximately) to the
 * target page, or NULL --- outside callers typically pass NULL since they
 * have not done such a search, but internal recursion cases pass the stack
 * to avoid duplicated search effort.
 *
 * Returns the number of pages successfully deleted (zero if page cannot
 * be deleted now; could be more than one if parent pages were deleted too).
 *
 * NOTE: this leaks memory.  Rather than trying to clean up everything
 * carefully, it's better to run it in a temp context that can be reset
 * frequently.
 */
int
_bt_pagedel(Relation rel, Buffer buf, BTStack stack, bool vacuum_full)
{
	int			result;
	BlockNumber target,
				leftsib,
				rightsib,
				parent;
	OffsetNumber poffset,
				maxoff;
	uint32		targetlevel,
				ilevel;
	ItemId		itemid;
	IndexTuple	targetkey,
				itup;
	ScanKey		itup_scankey;
	Buffer		lbuf,
				rbuf,
				pbuf;
	bool		parent_half_dead;
	bool		parent_one_child;
	bool		rightsib_empty;
	Buffer		metabuf = InvalidBuffer;
	Page		metapg = NULL;
	BTMetaPageData *metad = NULL;
	Page		page;
	BTPageOpaque opaque;

	MIRROREDLOCK_BUFMGR_MUST_ALREADY_BE_HELD;

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

	/*
	 * We can never delete rightmost pages nor root pages.	While at it, check
	 * that page is not already deleted and is empty.
	 */
	page = BufferGetPage(buf);
	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
	if (P_RIGHTMOST(opaque) || P_ISROOT(opaque) || P_ISDELETED(opaque) ||
		P_FIRSTDATAKEY(opaque) <= PageGetMaxOffsetNumber(page))
	{
		/* Should never fail to delete a half-dead page */
		Assert(!P_ISHALFDEAD(opaque));

		_bt_relbuf(rel, buf);
		return 0;
	}

	/*
	 * Save info about page, including a copy of its high key (it must have
	 * one, being non-rightmost).
	 */
	target = BufferGetBlockNumber(buf);
	targetlevel = opaque->btpo.level;
	leftsib = opaque->btpo_prev;
	itemid = PageGetItemId(page, P_HIKEY);
	targetkey = CopyIndexTuple((IndexTuple) PageGetItem(page, itemid));

	/*
	 * To avoid deadlocks, we'd better drop the target page lock before going
	 * further.
	 */
	_bt_relbuf(rel, buf);

	/*
	 * We need an approximate pointer to the page's parent page.  We use the
	 * standard search mechanism to search for the page's high key; this will
	 * give us a link to either the current parent or someplace to its left
	 * (if there are multiple equal high keys).  In recursion cases, the
	 * caller already generated a search stack and we can just re-use that
	 * work.
	 */
	if (stack == NULL)
	{
		if (!InRecovery)
		{
			/* we need an insertion scan key to do our search, so build one */
			itup_scankey = _bt_mkscankey(rel, targetkey);
			/* find the leftmost leaf page containing this key */
			stack = _bt_search(rel, rel->rd_rel->relnatts, itup_scankey, false,
							   &lbuf, BT_READ);
			/* don't need a pin on that either */
			_bt_relbuf(rel, lbuf);

			/*
			 * If we are trying to delete an interior page, _bt_search did
			 * more than we needed.  Locate the stack item pointing to our
			 * parent level.
			 */
			ilevel = 0;
			for (;;)
			{
				if (stack == NULL)
					elog(ERROR, "not enough stack items");
				if (ilevel == targetlevel)
					break;
				stack = stack->bts_parent;
				ilevel++;
			}
		}
		else
		{
			/*
			 * During WAL recovery, we can't use _bt_search (for one reason,
			 * it might invoke user-defined comparison functions that expect
			 * facilities not available in recovery mode).	Instead, just set
			 * up a dummy stack pointing to the left end of the parent tree
			 * level, from which _bt_getstackbuf will walk right to the parent
			 * page.  Painful, but we don't care too much about performance in
			 * this scenario.
			 */
			pbuf = _bt_get_endpoint(rel, targetlevel + 1, false);
			stack = (BTStack) palloc(sizeof(BTStackData));
			stack->bts_blkno = BufferGetBlockNumber(pbuf);
			stack->bts_offset = InvalidOffsetNumber;
			/* bts_btentry will be initialized below */
			stack->bts_parent = NULL;
			_bt_relbuf(rel, pbuf);
		}
	}

	/*
	 * We cannot delete a page that is the rightmost child of its immediate
	 * parent, unless it is the only child --- in which case the parent has to
	 * be deleted too, and the same condition applies recursively to it. We
	 * have to check this condition all the way up before trying to delete. We
	 * don't need to re-test when deleting a non-leaf page, though.
	 */
	if (targetlevel == 0 &&
		!_bt_parent_deletion_safe(rel, target, stack))
		return 0;

	/*
	 * We have to lock the pages we need to modify in the standard order:
	 * moving right, then up.  Else we will deadlock against other writers.
	 *
	 * So, we need to find and write-lock the current left sibling of the
	 * target page.  The sibling that was current a moment ago could have
	 * split, so we may have to move right.  This search could fail if either
	 * the sibling or the target page was deleted by someone else meanwhile;
	 * if so, give up.	(Right now, that should never happen, since page
	 * deletion is only done in VACUUM and there shouldn't be multiple VACUUMs
	 * concurrently on the same table.)
	 */
	if (leftsib != P_NONE)
	{
		lbuf = _bt_getbuf(rel, leftsib, BT_WRITE);
		page = BufferGetPage(lbuf);
		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
		while (P_ISDELETED(opaque) || opaque->btpo_next != target)
		{
			/* step right one page */
			leftsib = opaque->btpo_next;
			_bt_relbuf(rel, lbuf);
			if (leftsib == P_NONE)
			{
				elog(LOG, "no left sibling (concurrent deletion?) in \"%s\"",
					 RelationGetRelationName(rel));
				return 0;
			}
			lbuf = _bt_getbuf(rel, leftsib, BT_WRITE);
			page = BufferGetPage(lbuf);
			opaque = (BTPageOpaque) PageGetSpecialPointer(page);
		}
	}
	else
		lbuf = InvalidBuffer;

	/*
	 * Next write-lock the target page itself.	It should be okay to take just
	 * a write lock not a superexclusive lock, since no scans would stop on an
	 * empty page.
	 */
	buf = _bt_getbuf(rel, target, BT_WRITE);
	page = BufferGetPage(buf);
	opaque = (BTPageOpaque) PageGetSpecialPointer(page);

	/*
	 * Check page is still empty etc, else abandon deletion.  The empty check
	 * is necessary since someone else might have inserted into it while we
	 * didn't have it locked; the others are just for paranoia's sake.
	 */
	if (P_RIGHTMOST(opaque) || P_ISROOT(opaque) || P_ISDELETED(opaque) ||
		P_FIRSTDATAKEY(opaque) <= PageGetMaxOffsetNumber(page))
	{
		_bt_relbuf(rel, buf);
		if (BufferIsValid(lbuf))
			_bt_relbuf(rel, lbuf);
		return 0;
	}
	if (opaque->btpo_prev != leftsib)
		elog(ERROR, "left link changed unexpectedly in block %u of index \"%s\"",
			 target, RelationGetRelationName(rel));

	/*
	 * And next write-lock the (current) right sibling.
	 */
	rightsib = opaque->btpo_next;
	rbuf = _bt_getbuf(rel, rightsib, BT_WRITE);
	page = BufferGetPage(rbuf);
	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
	if (opaque->btpo_prev != target)
		elog(ERROR, "right sibling's left-link doesn't match: "
			 "block %u links to %u instead of expected %u in index \"%s\"",
			 rightsib, opaque->btpo_prev, target,
			 RelationGetRelationName(rel));

	/*
	 * Next find and write-lock the current parent of the target page. This is
	 * essentially the same as the corresponding step of splitting.
	 */
	ItemPointerSet(&(stack->bts_btentry.t_tid), target, P_HIKEY);
	pbuf = _bt_getstackbuf(rel, stack, BT_WRITE);
	if (pbuf == InvalidBuffer)
		elog(ERROR, "failed to re-find parent key in index \"%s\" for deletion target page %u",
			 RelationGetRelationName(rel), target);
	parent = stack->bts_blkno;
	poffset = stack->bts_offset;

	/*
	 * If the target is the rightmost child of its parent, then we can't
	 * delete, unless it's also the only child --- in which case the parent
	 * changes to half-dead status.  The "can't delete" case should have been
	 * detected by _bt_parent_deletion_safe, so complain if we see it now.
	 */
	page = BufferGetPage(pbuf);
	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
	maxoff = PageGetMaxOffsetNumber(page);
	parent_half_dead = false;
	parent_one_child = false;
	if (poffset >= maxoff)
	{
		if (poffset == P_FIRSTDATAKEY(opaque))
			parent_half_dead = true;
		else
			elog(ERROR, "failed to delete rightmost child %u of block %u in index \"%s\"",
				 target, parent, RelationGetRelationName(rel));
	}
	else
	{
		/* Will there be exactly one child left in this parent? */
		if (OffsetNumberNext(P_FIRSTDATAKEY(opaque)) == maxoff)
			parent_one_child = true;
	}

	/*
	 * If we are deleting the next-to-last page on the target's level, then
	 * the rightsib is a candidate to become the new fast root. (In theory, it
	 * might be possible to push the fast root even further down, but the odds
	 * of doing so are slim, and the locking considerations daunting.)
	 *
	 * We don't support handling this in the case where the parent is becoming
	 * half-dead, even though it theoretically could occur.
	 *
	 * We can safely acquire a lock on the metapage here --- see comments for
	 * _bt_newroot().
	 */
	if (leftsib == P_NONE && !parent_half_dead)
	{
		page = BufferGetPage(rbuf);
		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
		Assert(opaque->btpo.level == targetlevel);
		if (P_RIGHTMOST(opaque))
		{
			/* rightsib will be the only one left on the level */
			metabuf = _bt_getbuf(rel, BTREE_METAPAGE, BT_WRITE);
			metapg = BufferGetPage(metabuf);
			metad = BTPageGetMeta(metapg);

			/*
			 * The expected case here is btm_fastlevel == targetlevel+1; if
			 * the fastlevel is <= targetlevel, something is wrong, and we
			 * choose to overwrite it to fix it.
			 */
			if (metad->btm_fastlevel > targetlevel + 1)
			{
				/* no update wanted */
				_bt_relbuf(rel, metabuf);
				metabuf = InvalidBuffer;
			}
		}
	}

	/*
	 * Check that the parent-page index items we're about to delete/overwrite
	 * contain what we expect.  This can fail if the index has become
	 * corrupt for some reason.  We want to throw any error before entering
	 * the critical section --- otherwise it'd be a PANIC.
	 *
	 * The test on the target item is just an Assert because _bt_getstackbuf
	 * should have guaranteed it has the expected contents.  The test on the
	 * next-child downlink is known to sometimes fail in the field, though.
	 */
	page = BufferGetPage(pbuf);
	opaque = (BTPageOpaque) PageGetSpecialPointer(page);

#ifdef USE_ASSERT_CHECKING
	itemid = PageGetItemId(page, poffset);
	itup = (IndexTuple) PageGetItem(page, itemid);
	Assert(ItemPointerGetBlockNumber(&(itup->t_tid)) == target);
#endif

	if (!parent_half_dead)
	{
		OffsetNumber nextoffset;

		nextoffset = OffsetNumberNext(poffset);
		itemid = PageGetItemId(page, nextoffset);
		itup = (IndexTuple) PageGetItem(page, itemid);
		if (ItemPointerGetBlockNumber(&(itup->t_tid)) != rightsib)
			elog(ERROR, "right sibling %u of block %u is not next child %u of block %u in index \"%s\"",
				 rightsib, target, ItemPointerGetBlockNumber(&(itup->t_tid)),
				 parent, RelationGetRelationName(rel));
	}

	/*
	 * Here we begin doing the deletion.
	 */

	/* No ereport(ERROR) until changes are logged */
	START_CRIT_SECTION();

	/*
	 * Update parent.  The normal case is a tad tricky because we want to
	 * delete the target's downlink and the *following* key.  Easiest way is
	 * to copy the right sibling's downlink over the target downlink, and then
	 * delete the following item.
	 */
	if (parent_half_dead)
	{
		PageIndexTupleDelete(page, poffset);
		opaque->btpo_flags |= BTP_HALF_DEAD;
	}
	else
	{
		OffsetNumber nextoffset;

		itemid = PageGetItemId(page, poffset);
		itup = (IndexTuple) PageGetItem(page, itemid);
		ItemPointerSet(&(itup->t_tid), rightsib, P_HIKEY);

		nextoffset = OffsetNumberNext(poffset);
		PageIndexTupleDelete(page, nextoffset);
	}

	/*
	 * Update siblings' side-links.  Note the target page's side-links will
	 * continue to point to the siblings.  Asserts here are just rechecking
	 * things we already verified above.
	 */
	if (BufferIsValid(lbuf))
	{
		page = BufferGetPage(lbuf);
		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
		Assert(opaque->btpo_next == target);
		opaque->btpo_next = rightsib;
	}
	page = BufferGetPage(rbuf);
	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
	Assert(opaque->btpo_prev == target);
	opaque->btpo_prev = leftsib;
	rightsib_empty = (P_FIRSTDATAKEY(opaque) > PageGetMaxOffsetNumber(page));

	/*
	 * Mark the page itself deleted.  It can be recycled when all current
	 * transactions are gone; or immediately if we're doing VACUUM FULL.
	 */
	page = BufferGetPage(buf);
	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
	opaque->btpo_flags &= ~BTP_HALF_DEAD;
	opaque->btpo_flags |= BTP_DELETED;
	opaque->btpo.xact =
		vacuum_full ? FrozenTransactionId : ReadNewTransactionId();

	/* And update the metapage, if needed */
	if (BufferIsValid(metabuf))
	{
		metad->btm_fastroot = rightsib;
		metad->btm_fastlevel = targetlevel;
		MarkBufferDirty(metabuf);
	}

	/* Must mark buffers dirty before XLogInsert */
	MarkBufferDirty(pbuf);
	MarkBufferDirty(rbuf);
	MarkBufferDirty(buf);
	if (BufferIsValid(lbuf))
		MarkBufferDirty(lbuf);

	/* XLOG stuff */
	if (!rel->rd_istemp)
	{
		xl_btree_delete_page xlrec;
		xl_btree_metadata xlmeta;
		uint8		xlinfo;
		XLogRecPtr	recptr;
		XLogRecData rdata[5];
		XLogRecData *nextrdata;

		xl_btreetid_set(&(xlrec.target), rel, parent, poffset);
		xlrec.deadblk = target;
		xlrec.leftblk = leftsib;
		xlrec.rightblk = rightsib;

		rdata[0].data = (char *) &xlrec;
		rdata[0].len = SizeOfBtreeDeletePage;
		rdata[0].buffer = InvalidBuffer;
		rdata[0].next = nextrdata = &(rdata[1]);

		if (BufferIsValid(metabuf))
		{
			xlmeta.root = metad->btm_root;
			xlmeta.level = metad->btm_level;
			xlmeta.fastroot = metad->btm_fastroot;
			xlmeta.fastlevel = metad->btm_fastlevel;

			nextrdata->data = (char *) &xlmeta;
			nextrdata->len = sizeof(xl_btree_metadata);
			nextrdata->buffer = InvalidBuffer;
			nextrdata->next = nextrdata + 1;
			nextrdata++;
			xlinfo = XLOG_BTREE_DELETE_PAGE_META;
		}
		else if (parent_half_dead)
			xlinfo = XLOG_BTREE_DELETE_PAGE_HALF;
		else
			xlinfo = XLOG_BTREE_DELETE_PAGE;

		nextrdata->data = NULL;
		nextrdata->len = 0;
		nextrdata->next = nextrdata + 1;
		nextrdata->buffer = pbuf;
		nextrdata->buffer_std = true;
		nextrdata++;

		nextrdata->data = NULL;
		nextrdata->len = 0;
		nextrdata->buffer = rbuf;
		nextrdata->buffer_std = true;
		nextrdata->next = NULL;

		if (BufferIsValid(lbuf))
		{
			nextrdata->next = nextrdata + 1;
			nextrdata++;
			nextrdata->data = NULL;
			nextrdata->len = 0;
			nextrdata->buffer = lbuf;
			nextrdata->buffer_std = true;
			nextrdata->next = NULL;
		}

		recptr = XLogInsert(RM_BTREE_ID, xlinfo, rdata);

		if (BufferIsValid(metabuf))
		{
			PageSetLSN(metapg, recptr);
			PageSetTLI(metapg, ThisTimeLineID);
		}
		page = BufferGetPage(pbuf);
		PageSetLSN(page, recptr);
		PageSetTLI(page, ThisTimeLineID);
		page = BufferGetPage(rbuf);
		PageSetLSN(page, recptr);
		PageSetTLI(page, ThisTimeLineID);
		page = BufferGetPage(buf);
		PageSetLSN(page, recptr);
		PageSetTLI(page, ThisTimeLineID);
		if (BufferIsValid(lbuf))
		{
			page = BufferGetPage(lbuf);
			PageSetLSN(page, recptr);
			PageSetTLI(page, ThisTimeLineID);
		}
	}

	END_CRIT_SECTION();

	/* release metapage; send out relcache inval if metapage changed */
	if (BufferIsValid(metabuf))
	{
		CacheInvalidateRelcache(rel);
		_bt_relbuf(rel, metabuf);
	}
	/* can always release leftsib immediately */
	if (BufferIsValid(lbuf))
		_bt_relbuf(rel, lbuf);

	/*
	 * If parent became half dead, recurse to delete it. Otherwise, if right
	 * sibling is empty and is now the last child of the parent, recurse to
	 * try to delete it.  (These cases cannot apply at the same time, though
	 * the second case might itself recurse to the first.)
	 *
	 * When recursing to parent, we hold the lock on the target page until
	 * done.  This delays any insertions into the keyspace that was just
	 * effectively reassigned to the parent's right sibling.  If we allowed
	 * that, and there were enough such insertions before we finish deleting
	 * the parent, page splits within that keyspace could lead to inserting
	 * out-of-order keys into the grandparent level.  It is thought that that
	 * wouldn't have any serious consequences, but it still seems like a
	 * pretty bad idea.
	 */
	if (parent_half_dead)
	{
		/* recursive call will release pbuf */
		_bt_relbuf(rel, rbuf);
		result = _bt_pagedel(rel, pbuf, stack->bts_parent, vacuum_full) + 1;
		_bt_relbuf(rel, buf);
	}
	else if (parent_one_child && rightsib_empty)
	{
		_bt_relbuf(rel, pbuf);
		_bt_relbuf(rel, buf);
		/* recursive call will release rbuf */
		result = _bt_pagedel(rel, rbuf, stack, vacuum_full) + 1;
	}
	else
	{
		_bt_relbuf(rel, pbuf);
		_bt_relbuf(rel, buf);
		_bt_relbuf(rel, rbuf);
		result = 1;
	}

	return result;
}
示例#29
0
文件: nbtpage.c 项目: 50wu/gpdb
/*
 * Delete item(s) from a btree page.
 *
 * This must only be used for deleting leaf items.	Deleting an item on a
 * non-leaf page has to be done as part of an atomic action that includes
 * deleting the page it points to.
 *
 * This routine assumes that the caller has pinned and locked the buffer.
 * Also, the given itemnos *must* appear in increasing order in the array.
 */
void
_bt_delitems(Relation rel, Buffer buf,
			 OffsetNumber *itemnos, int nitems,
			 bool inVacuum)
{
	Page		page;
	BTPageOpaque opaque;

	MIRROREDLOCK_BUFMGR_MUST_ALREADY_BE_HELD;

	page = BufferGetPage(buf);

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

	/* No ereport(ERROR) until changes are logged */
	START_CRIT_SECTION();

	/* Fix the page */
	PageIndexMultiDelete(page, itemnos, nitems);

	/*
	 * If this is within VACUUM, we can clear the vacuum cycle ID since this
	 * page has certainly been processed by the current vacuum scan.
	 */
	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
	if (inVacuum)
		opaque->btpo_cycleid = 0;

	/*
	 * Mark the page as not containing any LP_DEAD items.  This is not
	 * certainly true (there might be some that have recently been marked, but
	 * weren't included in our target-item list), but it will almost always be
	 * true and it doesn't seem worth an additional page scan to check it.
	 * Remember that BTP_HAS_GARBAGE is only a hint anyway.
	 */
	opaque->btpo_flags &= ~BTP_HAS_GARBAGE;

	MarkBufferDirty(buf);

	/* XLOG stuff */
	if (!rel->rd_istemp)
	{
		xl_btree_delete xlrec;
		XLogRecPtr	recptr;
		XLogRecData rdata[2];

		xl_btreenode_set(&(xlrec.btreenode), rel);
		xlrec.block = BufferGetBlockNumber(buf);

		rdata[0].data = (char *) &xlrec;
		rdata[0].len = SizeOfBtreeDelete;
		rdata[0].buffer = InvalidBuffer;
		rdata[0].next = &(rdata[1]);

		/*
		 * The target-offsets array is not in the buffer, but pretend that it
		 * is.	When XLogInsert stores the whole buffer, the offsets array
		 * need not be stored too.
		 */
		if (nitems > 0)
		{
			rdata[1].data = (char *) itemnos;
			rdata[1].len = nitems * sizeof(OffsetNumber);
		}
		else
		{
			rdata[1].data = NULL;
			rdata[1].len = 0;
		}
		rdata[1].buffer = buf;
		rdata[1].buffer_std = true;
		rdata[1].next = NULL;

		recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_DELETE, rdata);

		PageSetLSN(page, recptr);
		PageSetTLI(page, ThisTimeLineID);
	}

	END_CRIT_SECTION();
}
示例#30
0
Datum
ginbulkdelete(PG_FUNCTION_ARGS)
{
	IndexVacuumInfo *info = (IndexVacuumInfo *) PG_GETARG_POINTER(0);
	IndexBulkDeleteResult *stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(1);
	IndexBulkDeleteCallback callback = (IndexBulkDeleteCallback) PG_GETARG_POINTER(2);
	void	   *callback_state = (void *) PG_GETARG_POINTER(3);
	Relation	index = info->index;
	BlockNumber blkno = GIN_ROOT_BLKNO;
	GinVacuumState gvs;
	Buffer		buffer;
	BlockNumber rootOfPostingTree[BLCKSZ / (sizeof(IndexTupleData) + sizeof(ItemId))];
	uint32		nRoot;

	gvs.index = index;
	gvs.callback = callback;
	gvs.callback_state = callback_state;
	gvs.strategy = info->strategy;
	initGinState(&gvs.ginstate, index);

	/* first time through? */
	if (stats == NULL)
	{
		/* Yes, so initialize stats to zeroes */
		stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
		/* and cleanup any pending inserts */
		ginInsertCleanup(&gvs.ginstate, true, stats);
	}

	/* we'll re-count the tuples each time */
	stats->num_index_tuples = 0;
	gvs.result = stats;

	buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
								RBM_NORMAL, info->strategy);

	/* find leaf page */
	for (;;)
	{
		Page		page = BufferGetPage(buffer);
		IndexTuple	itup;

		LockBuffer(buffer, GIN_SHARE);

		Assert(!GinPageIsData(page));

		if (GinPageIsLeaf(page))
		{
			LockBuffer(buffer, GIN_UNLOCK);
			LockBuffer(buffer, GIN_EXCLUSIVE);

			if (blkno == GIN_ROOT_BLKNO && !GinPageIsLeaf(page))
			{
				LockBuffer(buffer, GIN_UNLOCK);
				continue;		/* check it one more */
			}
			break;
		}

		Assert(PageGetMaxOffsetNumber(page) >= FirstOffsetNumber);

		itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, FirstOffsetNumber));
		blkno = GinGetDownlink(itup);
		Assert(blkno != InvalidBlockNumber);

		UnlockReleaseBuffer(buffer);
		buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
									RBM_NORMAL, info->strategy);
	}

	/* right now we found leftmost page in entry's BTree */

	for (;;)
	{
		Page		page = BufferGetPage(buffer);
		Page		resPage;
		uint32		i;

		Assert(!GinPageIsData(page));

		resPage = ginVacuumEntryPage(&gvs, buffer, rootOfPostingTree, &nRoot);

		blkno = GinPageGetOpaque(page)->rightlink;

		if (resPage)
		{
			START_CRIT_SECTION();
			PageRestoreTempPage(resPage, page);
			MarkBufferDirty(buffer);
			xlogVacuumPage(gvs.index, buffer);
			UnlockReleaseBuffer(buffer);
			END_CRIT_SECTION();
		}
		else
		{
			UnlockReleaseBuffer(buffer);
		}

		vacuum_delay_point();

		for (i = 0; i < nRoot; i++)
		{
			ginVacuumPostingTree(&gvs, rootOfPostingTree[i]);
			vacuum_delay_point();
		}

		if (blkno == InvalidBlockNumber)		/* rightmost page */
			break;

		buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
									RBM_NORMAL, info->strategy);
		LockBuffer(buffer, GIN_EXCLUSIVE);
	}

	PG_RETURN_POINTER(gvs.result);
}