/*-------------------------------------------------------------------------
 *
 * ginxlog.c
 *	  WAL replay logic for inverted index.
 *
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *			 src/backend/access/gin/ginxlog.c
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/gin_private.h"
#include "access/xlogutils.h"
#include "utils/memutils.h"

static MemoryContext opCtx;		/* working memory for operations */

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);
}

static void
ginRedoCreateIndex(XLogRecPtr lsn, XLogRecord *record)
{
	RelFileNode *node = (RelFileNode *) XLogRecGetData(record);
	Buffer		RootBuffer,
				MetaBuffer;
	Page		page;

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

	MetaBuffer = XLogReadBuffer(*node, GIN_METAPAGE_BLKNO, true);
	Assert(BufferIsValid(MetaBuffer));
	page = (Page) BufferGetPage(MetaBuffer);

	GinInitMetabuffer(MetaBuffer);

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

	RootBuffer = XLogReadBuffer(*node, GIN_ROOT_BLKNO, true);
	Assert(BufferIsValid(RootBuffer));
	page = (Page) BufferGetPage(RootBuffer);

	GinInitBuffer(RootBuffer, GIN_LEAF);

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

	UnlockReleaseBuffer(RootBuffer);
	UnlockReleaseBuffer(MetaBuffer);
}

static void
ginRedoCreatePTree(XLogRecPtr lsn, XLogRecord *record)
{
	ginxlogCreatePostingTree *data = (ginxlogCreatePostingTree *) XLogRecGetData(record);
	ItemPointerData *items = (ItemPointerData *) (XLogRecGetData(record) + sizeof(ginxlogCreatePostingTree));
	Buffer		buffer;
	Page		page;

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

	buffer = XLogReadBuffer(data->node, data->blkno, true);
	Assert(BufferIsValid(buffer));
	page = (Page) BufferGetPage(buffer);

	GinInitBuffer(buffer, GIN_DATA | GIN_LEAF);
	memcpy(GinDataPageGetData(page), items, sizeof(ItemPointerData) * data->nitem);
	GinPageGetOpaque(page)->maxoff = data->nitem;

	PageSetLSN(page, lsn);

	MarkBufferDirty(buffer);
	UnlockReleaseBuffer(buffer);
}

static void
ginRedoInsertEntry(Buffer buffer, OffsetNumber offset, BlockNumber rightblkno,
				   void *rdata)
{
	Page		page = BufferGetPage(buffer);
	ginxlogInsertEntry *data = (ginxlogInsertEntry *) rdata;
	IndexTuple	itup;

	if (rightblkno != InvalidBlockNumber)
	{
		/* update link to right page after split */
		Assert(!GinPageIsLeaf(page));
		Assert(offset >= FirstOffsetNumber && offset <= PageGetMaxOffsetNumber(page));
		itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, offset));
		GinSetDownlink(itup, rightblkno);
	}

	if (data->isDelete)
	{
		Assert(GinPageIsLeaf(page));
		Assert(offset >= FirstOffsetNumber && offset <= PageGetMaxOffsetNumber(page));
		PageIndexTupleDelete(page, offset);
	}

	itup = &data->tuple;

	if (PageAddItem(page, (Item) itup, IndexTupleSize(itup), offset, false, false) == InvalidOffsetNumber)
	{
		RelFileNode node;
		ForkNumber forknum;
		BlockNumber blknum;

		BufferGetTag(buffer, &node, &forknum, &blknum);
		elog(ERROR, "failed to add item to index page in %u/%u/%u",
			 node.spcNode, node.dbNode, node.relNode);
	}
}

static void
ginRedoInsertData(Buffer buffer, OffsetNumber offset, BlockNumber rightblkno,
				  void *rdata)
{
	Page		page = BufferGetPage(buffer);

	if (GinPageIsLeaf(page))
	{
		ginxlogInsertDataLeaf *data = (ginxlogInsertDataLeaf *) rdata;
		ItemPointerData *items = data->items;
		OffsetNumber i;

		for (i = 0; i < data->nitem; i++)
			GinDataPageAddItemPointer(page, &items[i], offset + i);
	}
	else
	{
		PostingItem *pitem = (PostingItem *) rdata;
		PostingItem *oldpitem;

		/* update link to right page after split */
		oldpitem = GinDataPageGetPostingItem(page, offset);
		PostingItemSetBlockNumber(oldpitem, rightblkno);

		GinDataPageAddPostingItem(page, pitem, offset);
	}
}

static void
ginRedoInsert(XLogRecPtr lsn, XLogRecord *record)
{
	ginxlogInsert *data = (ginxlogInsert *) XLogRecGetData(record);
	Buffer		buffer;
	Page		page;
	char	   *payload;
	BlockNumber leftChildBlkno = InvalidBlockNumber;
	BlockNumber rightChildBlkno = InvalidBlockNumber;
	bool		isLeaf = (data->flags & GIN_INSERT_ISLEAF) != 0;

	payload = XLogRecGetData(record) + sizeof(ginxlogInsert);

	/*
	 * First clear incomplete-split flag on child page if this finishes
	 * a split.
	 */
	if (!isLeaf)
	{
		leftChildBlkno = BlockIdGetBlockNumber((BlockId) payload);
		payload += sizeof(BlockIdData);
		rightChildBlkno = BlockIdGetBlockNumber((BlockId) payload);
		payload += sizeof(BlockIdData);

		if (record->xl_info & XLR_BKP_BLOCK(0))
			(void) RestoreBackupBlock(lsn, record, 0, false, false);
		else
			ginRedoClearIncompleteSplit(lsn, data->node, leftChildBlkno);
	}

	/* If we have a full-page image, restore it and we're done */
	if (record->xl_info & XLR_BKP_BLOCK(isLeaf ? 0 : 1))
	{
		(void) RestoreBackupBlock(lsn, record, isLeaf ? 0 : 1, false, false);
		return;
	}

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

	if (lsn > PageGetLSN(page))
	{
		/* How to insert the payload is tree-type specific */
		if (data->flags & GIN_INSERT_ISDATA)
		{
			Assert(GinPageIsData(page));
			ginRedoInsertData(buffer, data->offset, rightChildBlkno, payload);
		}
		else
		{
			Assert(!GinPageIsData(page));
			ginRedoInsertEntry(buffer, data->offset, rightChildBlkno, payload);
		}

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

	UnlockReleaseBuffer(buffer);
}

static void
ginRedoSplitEntry(Page lpage, Page rpage, void *rdata)
{
	ginxlogSplitEntry *data = (ginxlogSplitEntry *) rdata;
	IndexTuple	itup = (IndexTuple) ((char *) rdata + sizeof(ginxlogSplitEntry));
	OffsetNumber i;

	for (i = 0; i < data->separator; i++)
	{
		if (PageAddItem(lpage, (Item) itup, IndexTupleSize(itup), InvalidOffsetNumber, false, false) == InvalidOffsetNumber)
			elog(ERROR, "failed to add item to gin index page");
		itup = (IndexTuple) (((char *) itup) + MAXALIGN(IndexTupleSize(itup)));
	}

	for (i = data->separator; i < data->nitem; i++)
	{
		if (PageAddItem(rpage, (Item) itup, IndexTupleSize(itup), InvalidOffsetNumber, false, false) == InvalidOffsetNumber)
			elog(ERROR, "failed to add item to gin index page");
		itup = (IndexTuple) (((char *) itup) + MAXALIGN(IndexTupleSize(itup)));
	}
}

static void
ginRedoSplitData(Page lpage, Page rpage, void *rdata)
{
	ginxlogSplitData *data = (ginxlogSplitData *) rdata;
	bool		isleaf = GinPageIsLeaf(lpage);
	char	   *ptr = (char *) rdata + sizeof(ginxlogSplitData);
	OffsetNumber i;
	ItemPointer bound;

	if (isleaf)
	{
		ItemPointer items = (ItemPointer) ptr;
		for (i = 0; i < data->separator; i++)
			GinDataPageAddItemPointer(lpage, &items[i], InvalidOffsetNumber);
		for (i = data->separator; i < data->nitem; i++)
			GinDataPageAddItemPointer(rpage, &items[i], InvalidOffsetNumber);
	}
	else
	{
		PostingItem *items = (PostingItem *) ptr;
		for (i = 0; i < data->separator; i++)
			GinDataPageAddPostingItem(lpage, &items[i], InvalidOffsetNumber);
		for (i = data->separator; i < data->nitem; i++)
			GinDataPageAddPostingItem(rpage, &items[i], InvalidOffsetNumber);
	}

	/* set up right key */
	bound = GinDataPageGetRightBound(lpage);
	if (isleaf)
		*bound = *GinDataPageGetItemPointer(lpage, GinPageGetOpaque(lpage)->maxoff);
	else
		*bound = GinDataPageGetPostingItem(lpage, GinPageGetOpaque(lpage)->maxoff)->key;

	bound = GinDataPageGetRightBound(rpage);
	*bound = data->rightbound;
}

static void
ginRedoSplit(XLogRecPtr lsn, XLogRecord *record)
{
	ginxlogSplit *data = (ginxlogSplit *) XLogRecGetData(record);
	Buffer		lbuffer,
				rbuffer;
	Page		lpage,
				rpage;
	uint32		flags = 0;
	char	   *payload;
	bool		isLeaf = (data->flags & GIN_INSERT_ISLEAF) != 0;
	bool		isData = (data->flags & GIN_INSERT_ISDATA) != 0;
	bool		isRoot = (data->flags & GIN_SPLIT_ROOT) != 0;

	payload = XLogRecGetData(record) + sizeof(ginxlogSplit);

	/*
	 * First clear incomplete-split flag on child page if this finishes
	 * a split
	 */
	if (!isLeaf)
	{
		if (record->xl_info & XLR_BKP_BLOCK(0))
			(void) RestoreBackupBlock(lsn, record, 0, false, false);
		else
			ginRedoClearIncompleteSplit(lsn, data->node, data->leftChildBlkno);
	}

	if (isLeaf)
		flags |= GIN_LEAF;

	if (isData)
		flags |= GIN_DATA;

	lbuffer = XLogReadBuffer(data->node, data->lblkno, true);
	Assert(BufferIsValid(lbuffer));
	lpage = (Page) BufferGetPage(lbuffer);
	GinInitBuffer(lbuffer, flags);

	rbuffer = XLogReadBuffer(data->node, data->rblkno, true);
	Assert(BufferIsValid(rbuffer));
	rpage = (Page) BufferGetPage(rbuffer);
	GinInitBuffer(rbuffer, flags);

	GinPageGetOpaque(lpage)->rightlink = BufferGetBlockNumber(rbuffer);
	GinPageGetOpaque(rpage)->rightlink = isRoot ? InvalidBlockNumber : data->rrlink;

	/* Do the tree-type specific portion to restore the page contents */
	if (isData)
		ginRedoSplitData(lpage, rpage, payload);
	else
		ginRedoSplitEntry(lpage, rpage, payload);

	PageSetLSN(rpage, lsn);
	MarkBufferDirty(rbuffer);

	PageSetLSN(lpage, lsn);
	MarkBufferDirty(lbuffer);

	if (isRoot)
	{
		BlockNumber	rootBlkno = data->rrlink;
		Buffer		rootBuf = XLogReadBuffer(data->node, rootBlkno, true);
		Page		rootPage = BufferGetPage(rootBuf);

		GinInitBuffer(rootBuf, flags & ~GIN_LEAF);

		if (isData)
		{
			Assert(rootBlkno != GIN_ROOT_BLKNO);
			ginDataFillRoot(NULL, BufferGetPage(rootBuf),
							BufferGetBlockNumber(lbuffer),
							BufferGetPage(lbuffer),
							BufferGetBlockNumber(rbuffer),
							BufferGetPage(rbuffer));
		}
		else
		{
			Assert(rootBlkno == GIN_ROOT_BLKNO);
			ginEntryFillRoot(NULL, BufferGetPage(rootBuf),
							 BufferGetBlockNumber(lbuffer),
							 BufferGetPage(lbuffer),
							 BufferGetBlockNumber(rbuffer),
							 BufferGetPage(rbuffer));
		}

		PageSetLSN(rootPage, lsn);

		MarkBufferDirty(rootBuf);
		UnlockReleaseBuffer(rootBuf);
	}

	UnlockReleaseBuffer(rbuffer);
	UnlockReleaseBuffer(lbuffer);
}

static void
ginRedoVacuumPage(XLogRecPtr lsn, XLogRecord *record)
{
	ginxlogVacuumPage *data = (ginxlogVacuumPage *) XLogRecGetData(record);
	Buffer		buffer;
	Page		page;

	/* If we have a full-page image, restore it and we're done */
	if (record->xl_info & XLR_BKP_BLOCK(0))
	{
		(void) RestoreBackupBlock(lsn, record, 0, false, false);
		return;
	}

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

	if (lsn > PageGetLSN(page))
	{
		if (GinPageIsData(page))
		{
			memcpy(GinDataPageGetData(page),
				   XLogRecGetData(record) + sizeof(ginxlogVacuumPage),
				   data->nitem * GinSizeOfDataPageItem(page));
			GinPageGetOpaque(page)->maxoff = data->nitem;
		}
		else
		{
			OffsetNumber i,
					   *tod;
			IndexTuple	itup = (IndexTuple) (XLogRecGetData(record) + sizeof(ginxlogVacuumPage));

			tod = (OffsetNumber *) palloc(sizeof(OffsetNumber) * PageGetMaxOffsetNumber(page));
			for (i = FirstOffsetNumber; i <= PageGetMaxOffsetNumber(page); i++)
				tod[i - 1] = i;

			PageIndexMultiDelete(page, tod, PageGetMaxOffsetNumber(page));

			for (i = 0; i < data->nitem; i++)
			{
				if (PageAddItem(page, (Item) itup, IndexTupleSize(itup), InvalidOffsetNumber, false, false) == InvalidOffsetNumber)
					elog(ERROR, "failed to add item to index page in %u/%u/%u",
						 data->node.spcNode, data->node.dbNode, data->node.relNode);
				itup = (IndexTuple) (((char *) itup) + MAXALIGN(IndexTupleSize(itup)));
			}
		}

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

	UnlockReleaseBuffer(buffer);
}

static void
ginRedoDeletePage(XLogRecPtr lsn, XLogRecord *record)
{
	ginxlogDeletePage *data = (ginxlogDeletePage *) XLogRecGetData(record);
	Buffer		dbuffer;
	Buffer		pbuffer;
	Buffer		lbuffer;
	Page		page;

	if (record->xl_info & XLR_BKP_BLOCK(0))
		dbuffer = RestoreBackupBlock(lsn, record, 0, false, true);
	else
	{
		dbuffer = XLogReadBuffer(data->node, data->blkno, false);
		if (BufferIsValid(dbuffer))
		{
			page = BufferGetPage(dbuffer);
			if (lsn > PageGetLSN(page))
			{
				Assert(GinPageIsData(page));
				GinPageGetOpaque(page)->flags = GIN_DELETED;
				PageSetLSN(page, lsn);
				MarkBufferDirty(dbuffer);
			}
		}
	}

	if (record->xl_info & XLR_BKP_BLOCK(1))
		pbuffer = RestoreBackupBlock(lsn, record, 1, false, true);
	else
	{
		pbuffer = XLogReadBuffer(data->node, data->parentBlkno, false);
		if (BufferIsValid(pbuffer))
		{
			page = BufferGetPage(pbuffer);
			if (lsn > PageGetLSN(page))
			{
				Assert(GinPageIsData(page));
				Assert(!GinPageIsLeaf(page));
				GinPageDeletePostingItem(page, data->parentOffset);
				PageSetLSN(page, lsn);
				MarkBufferDirty(pbuffer);
			}
		}
	}

	if (record->xl_info & XLR_BKP_BLOCK(2))
		(void) RestoreBackupBlock(lsn, record, 2, false, false);
	else if (data->leftBlkno != InvalidBlockNumber)
	{
		lbuffer = XLogReadBuffer(data->node, data->leftBlkno, false);
		if (BufferIsValid(lbuffer))
		{
			page = BufferGetPage(lbuffer);
			if (lsn > PageGetLSN(page))
			{
				Assert(GinPageIsData(page));
				GinPageGetOpaque(page)->rightlink = data->rightLink;
				PageSetLSN(page, lsn);
				MarkBufferDirty(lbuffer);
			}
			UnlockReleaseBuffer(lbuffer);
		}
	}

	if (BufferIsValid(pbuffer))
		UnlockReleaseBuffer(pbuffer);
	if (BufferIsValid(dbuffer))
		UnlockReleaseBuffer(dbuffer);
}

static void
ginRedoUpdateMetapage(XLogRecPtr lsn, XLogRecord *record)
{
	ginxlogUpdateMeta *data = (ginxlogUpdateMeta *) XLogRecGetData(record);
	Buffer		metabuffer;
	Page		metapage;
	Buffer		buffer;

	metabuffer = XLogReadBuffer(data->node, GIN_METAPAGE_BLKNO, false);
	if (!BufferIsValid(metabuffer))
		return;					/* assume index was deleted, nothing to do */
	metapage = BufferGetPage(metabuffer);

	if (lsn > PageGetLSN(metapage))
	{
		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);
}

static void
ginRedoInsertListPage(XLogRecPtr lsn, XLogRecord *record)
{
	ginxlogInsertListPage *data = (ginxlogInsertListPage *) XLogRecGetData(record);
	Buffer		buffer;
	Page		page;
	OffsetNumber l,
				off = FirstOffsetNumber;
	int			i,
				tupsize;
	IndexTuple	tuples = (IndexTuple) (XLogRecGetData(record) + sizeof(ginxlogInsertListPage));

	/* If we have a full-page image, restore it and we're done */
	if (record->xl_info & XLR_BKP_BLOCK(0))
	{
		(void) RestoreBackupBlock(lsn, record, 0, false, false);
		return;
	}

	buffer = XLogReadBuffer(data->node, data->blkno, true);
	Assert(BufferIsValid(buffer));
	page = BufferGetPage(buffer);

	GinInitBuffer(buffer, GIN_LIST);
	GinPageGetOpaque(page)->rightlink = data->rightlink;
	if (data->rightlink == InvalidBlockNumber)
	{
		/* tail of sublist */
		GinPageSetFullRow(page);
		GinPageGetOpaque(page)->maxoff = 1;
	}
	else
	{
		GinPageGetOpaque(page)->maxoff = 0;
	}

	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);
	}

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

	UnlockReleaseBuffer(buffer);
}

static void
ginRedoDeleteListPages(XLogRecPtr lsn, XLogRecord *record)
{
	ginxlogDeleteListPages *data = (ginxlogDeleteListPages *) XLogRecGetData(record);
	Buffer		metabuffer;
	Page		metapage;
	int			i;

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

	metabuffer = XLogReadBuffer(data->node, GIN_METAPAGE_BLKNO, false);
	if (!BufferIsValid(metabuffer))
		return;					/* assume index was deleted, nothing to do */
	metapage = BufferGetPage(metabuffer);

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

	/*
	 * In normal operation, shiftList() takes exclusive lock on all the
	 * pages-to-be-deleted simultaneously.	During replay, however, it should
	 * be all right to lock them one at a time.  This is dependent on the fact
	 * that we are deleting pages from the head of the list, and that readers
	 * share-lock the next page before releasing the one they are on. So we
	 * cannot get past a reader that is on, or due to visit, any page we are
	 * going to delete.  New incoming readers will block behind our metapage
	 * lock and then see a fully updated page list.
	 */
	for (i = 0; i < data->ndeleted; i++)
	{
		Buffer		buffer = XLogReadBuffer(data->node, data->toDelete[i], false);

		if (BufferIsValid(buffer))
		{
			Page		page = BufferGetPage(buffer);

			if (lsn > PageGetLSN(page))
			{
				GinPageGetOpaque(page)->flags = GIN_DELETED;

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

			UnlockReleaseBuffer(buffer);
		}
	}
	UnlockReleaseBuffer(metabuffer);
}

void
gin_redo(XLogRecPtr lsn, XLogRecord *record)
{
	uint8		info = record->xl_info & ~XLR_INFO_MASK;
	MemoryContext oldCtx;

	/*
	 * GIN indexes do not require any conflict processing. NB: If we ever
	 * implement a similar optimization as we have in b-tree, and remove
	 * killed tuples outside VACUUM, we'll need to handle that here.
	 */

	oldCtx = MemoryContextSwitchTo(opCtx);
	switch (info)
	{
		case XLOG_GIN_CREATE_INDEX:
			ginRedoCreateIndex(lsn, record);
			break;
		case XLOG_GIN_CREATE_PTREE:
			ginRedoCreatePTree(lsn, record);
			break;
		case XLOG_GIN_INSERT:
			ginRedoInsert(lsn, record);
			break;
		case XLOG_GIN_SPLIT:
			ginRedoSplit(lsn, record);
			break;
		case XLOG_GIN_VACUUM_PAGE:
			ginRedoVacuumPage(lsn, record);
			break;
		case XLOG_GIN_DELETE_PAGE:
			ginRedoDeletePage(lsn, record);
			break;
		case XLOG_GIN_UPDATE_META_PAGE:
			ginRedoUpdateMetapage(lsn, record);
			break;
		case XLOG_GIN_INSERT_LISTPAGE:
			ginRedoInsertListPage(lsn, record);
			break;
		case XLOG_GIN_DELETE_LISTPAGE:
			ginRedoDeleteListPages(lsn, record);
			break;
		default:
			elog(PANIC, "gin_redo: unknown op code %u", info);
	}
	MemoryContextSwitchTo(oldCtx);
	MemoryContextReset(opCtx);
}

void
gin_xlog_startup(void)
{
	opCtx = AllocSetContextCreate(CurrentMemoryContext,
								  "GIN recovery temporary context",
								  ALLOCSET_DEFAULT_MINSIZE,
								  ALLOCSET_DEFAULT_INITSIZE,
								  ALLOCSET_DEFAULT_MAXSIZE);
}

void
gin_xlog_cleanup(void)
{
	MemoryContextDelete(opCtx);
}