Example #1
0
static void
ginRedoRecompress(Page page, ginxlogRecompressDataLeaf *data)
{
	int			actionno;
	int			segno;
	GinPostingList *oldseg;
	Pointer		segmentend;
	char	   *walbuf;
	int			totalsize;

	/*
	 * If the page is in pre-9.4 format, convert to new___ format first.
	 */
	if (!GinPageIsCompressed(page))
	{
		ItemPointer uncompressed = (ItemPointer) GinDataPageGetData(page);
		int			nuncompressed = GinPageGetOpaque(page)->maxoff;
		int			npacked;
		GinPostingList *plist;

		plist = ginCompressPostingList(uncompressed, nuncompressed,
									   BLCKSZ, &npacked);
		Assert(npacked == nuncompressed);

		totalsize = SizeOfGinPostingList(plist);

		memcpy(GinDataLeafPageGetPostingList(page), plist, totalsize);
		GinDataPageSetDataSize(page, totalsize);
		GinPageSetCompressed(page);
		GinPageGetOpaque(page)->maxoff = InvalidOffsetNumber;
	}

	oldseg = GinDataLeafPageGetPostingList(page);
	segmentend = (Pointer) oldseg + GinDataLeafPageGetPostingListSize(page);
	segno = 0;

	walbuf = ((char *) data) + sizeof(ginxlogRecompressDataLeaf);
	for (actionno = 0; actionno < data->nactions; actionno++)
	{
		uint8		a_segno = *((uint8 *) (walbuf++));
		uint8		a_action = *((uint8 *) (walbuf++));
		GinPostingList *newseg = NULL;
		int			newsegsize = 0;
		ItemPointerData *items = NULL;
		uint16		nitems = 0;
		ItemPointerData *olditems;
		int			nolditems;
		ItemPointerData *newitems;
		int			nnewitems;
		int			segsize;
		Pointer		segptr;
		int			szleft;

		/* Extract all the information we need from the WAL record */
		if (a_action == GIN_SEGMENT_INSERT ||
			a_action == GIN_SEGMENT_REPLACE)
		{
			newseg = (GinPostingList *) walbuf;
			newsegsize = SizeOfGinPostingList(newseg);
			walbuf += SHORTALIGN(newsegsize);
		}

		if (a_action == GIN_SEGMENT_ADDITEMS)
		{
			memcpy(&nitems, walbuf, sizeof(uint16));
			walbuf += sizeof(uint16);
			items = (ItemPointerData *) walbuf;
			walbuf += nitems * sizeof(ItemPointerData);
		}

		/* Skip to the segment that this action concerns */
		Assert(segno <= a_segno);
		while (segno < a_segno)
		{
			oldseg = GinNextPostingListSegment(oldseg);
			segno++;
		}

		/*
		 * ADDITEMS action is handled like REPLACE, but the new___ segment to
		 * replace the old one is reconstructed using the old segment from
		 * disk and the new___ items from the WAL record.
		 */
		if (a_action == GIN_SEGMENT_ADDITEMS)
		{
			int			npacked;

			olditems = ginPostingListDecode(oldseg, &nolditems);

			newitems = ginMergeItemPointers(items, nitems,
											olditems, nolditems,
											&nnewitems);
			Assert(nnewitems == nolditems + nitems);

			newseg = ginCompressPostingList(newitems, nnewitems,
											BLCKSZ, &npacked);
			Assert(npacked == nnewitems);

			newsegsize = SizeOfGinPostingList(newseg);
			a_action = GIN_SEGMENT_REPLACE;
		}

		segptr = (Pointer) oldseg;
		if (segptr != segmentend)
			segsize = SizeOfGinPostingList(oldseg);
		else
		{
			/*
			 * Positioned after the last existing segment. Only INSERTs
			 * expected here.
			 */
			Assert(a_action == GIN_SEGMENT_INSERT);
			segsize = 0;
		}
		szleft = segmentend - segptr;

		switch (a_action)
		{
			case GIN_SEGMENT_DELETE:
				memmove(segptr, segptr + segsize, szleft - segsize);
				segmentend -= segsize;

				segno++;
				break;

			case GIN_SEGMENT_INSERT:
				/* make room for the new___ segment */
				memmove(segptr + newsegsize, segptr, szleft);
				/* copy the new___ segment in place */
				memcpy(segptr, newseg, newsegsize);
				segmentend += newsegsize;
				segptr += newsegsize;
				break;

			case GIN_SEGMENT_REPLACE:
				/* shift the segments that follow */
				memmove(segptr + newsegsize,
						segptr + segsize,
						szleft - segsize);
				/* copy the replacement segment in place */
				memcpy(segptr, newseg, newsegsize);
				segmentend -= segsize;
				segmentend += newsegsize;
				segptr += newsegsize;
				segno++;
				break;

			default:
				elog(ERROR, "unexpected GIN leaf action: %u", a_action);
		}
		oldseg = (GinPostingList *) segptr;
	}

	totalsize = segmentend - (Pointer) GinDataLeafPageGetPostingList(page);
	GinDataPageSetDataSize(page, totalsize);
}
Example #2
0
/*
 * Redo recompression of posting list.  Doing all the changes in-place is not
 * always possible, because it might require more space than we've on the page.
 * Instead, once modification is required we copy unprocessed tail of the page
 * into separately allocated chunk of memory for further reading original
 * versions of segments.  Thanks to that we don't bother about moving page data
 * in-place.
 */
static void
ginRedoRecompress(Page page, ginxlogRecompressDataLeaf *data)
{
	int			actionno;
	int			segno;
	GinPostingList *oldseg;
	Pointer		segmentend;
	char	   *walbuf;
	int			totalsize;
	Pointer		tailCopy = NULL;
	Pointer		writePtr;
	Pointer		segptr;

	/*
	 * If the page is in pre-9.4 format, convert to new format first.
	 */
	if (!GinPageIsCompressed(page))
	{
		ItemPointer uncompressed = (ItemPointer) GinDataPageGetData(page);
		int			nuncompressed = GinPageGetOpaque(page)->maxoff;
		int			npacked;

		/*
		 * Empty leaf pages are deleted as part of vacuum, but leftmost and
		 * rightmost pages are never deleted.  So, pg_upgrade'd from pre-9.4
		 * instances might contain empty leaf pages, and we need to handle
		 * them correctly.
		 */
		if (nuncompressed > 0)
		{
			GinPostingList *plist;

			plist = ginCompressPostingList(uncompressed, nuncompressed,
										   BLCKSZ, &npacked);
			totalsize = SizeOfGinPostingList(plist);

			Assert(npacked == nuncompressed);

			memcpy(GinDataLeafPageGetPostingList(page), plist, totalsize);
		}
		else
		{
			totalsize = 0;
		}

		GinDataPageSetDataSize(page, totalsize);
		GinPageSetCompressed(page);
		GinPageGetOpaque(page)->maxoff = InvalidOffsetNumber;
	}

	oldseg = GinDataLeafPageGetPostingList(page);
	writePtr = (Pointer) oldseg;
	segmentend = (Pointer) oldseg + GinDataLeafPageGetPostingListSize(page);
	segno = 0;

	walbuf = ((char *) data) + sizeof(ginxlogRecompressDataLeaf);
	for (actionno = 0; actionno < data->nactions; actionno++)
	{
		uint8		a_segno = *((uint8 *) (walbuf++));
		uint8		a_action = *((uint8 *) (walbuf++));
		GinPostingList *newseg = NULL;
		int			newsegsize = 0;
		ItemPointerData *items = NULL;
		uint16		nitems = 0;
		ItemPointerData *olditems;
		int			nolditems;
		ItemPointerData *newitems;
		int			nnewitems;
		int			segsize;

		/* Extract all the information we need from the WAL record */
		if (a_action == GIN_SEGMENT_INSERT ||
			a_action == GIN_SEGMENT_REPLACE)
		{
			newseg = (GinPostingList *) walbuf;
			newsegsize = SizeOfGinPostingList(newseg);
			walbuf += SHORTALIGN(newsegsize);
		}

		if (a_action == GIN_SEGMENT_ADDITEMS)
		{
			memcpy(&nitems, walbuf, sizeof(uint16));
			walbuf += sizeof(uint16);
			items = (ItemPointerData *) walbuf;
			walbuf += nitems * sizeof(ItemPointerData);
		}

		/* Skip to the segment that this action concerns */
		Assert(segno <= a_segno);
		while (segno < a_segno)
		{
			/*
			 * Once modification is started and page tail is copied, we've
			 * to copy unmodified segments.
			 */
			segsize = SizeOfGinPostingList(oldseg);
			if (tailCopy)
			{
				Assert(writePtr + segsize < PageGetSpecialPointer(page));
				memcpy(writePtr, (Pointer) oldseg, segsize);
			}
			writePtr += segsize;
			oldseg = GinNextPostingListSegment(oldseg);
			segno++;
		}

		/*
		 * ADDITEMS action is handled like REPLACE, but the new segment to
		 * replace the old one is reconstructed using the old segment from
		 * disk and the new items from the WAL record.
		 */
		if (a_action == GIN_SEGMENT_ADDITEMS)
		{
			int			npacked;

			olditems = ginPostingListDecode(oldseg, &nolditems);

			newitems = ginMergeItemPointers(items, nitems,
											olditems, nolditems,
											&nnewitems);
			Assert(nnewitems == nolditems + nitems);

			newseg = ginCompressPostingList(newitems, nnewitems,
											BLCKSZ, &npacked);
			Assert(npacked == nnewitems);

			newsegsize = SizeOfGinPostingList(newseg);
			a_action = GIN_SEGMENT_REPLACE;
		}

		segptr = (Pointer) oldseg;
		if (segptr != segmentend)
			segsize = SizeOfGinPostingList(oldseg);
		else
		{
			/*
			 * Positioned after the last existing segment. Only INSERTs
			 * expected here.
			 */
			Assert(a_action == GIN_SEGMENT_INSERT);
			segsize = 0;
		}

		/*
		 * We're about to start modification of the page.  So, copy tail of the
		 * page if it's not done already.
		 */
		if (!tailCopy && segptr != segmentend)
		{
			int tailSize = segmentend - segptr;

			tailCopy = (Pointer) palloc(tailSize);
			memcpy(tailCopy, segptr, tailSize);
			segptr = tailCopy;
			oldseg = (GinPostingList *) segptr;
			segmentend = segptr + tailSize;
		}

		switch (a_action)
		{
			case GIN_SEGMENT_DELETE:
				segptr += segsize;
				segno++;
				break;

			case GIN_SEGMENT_INSERT:
				/* copy the new segment in place */
				Assert(writePtr + newsegsize <= PageGetSpecialPointer(page));
				memcpy(writePtr, newseg, newsegsize);
				writePtr += newsegsize;
				break;

			case GIN_SEGMENT_REPLACE:
				/* copy the new version of segment in place */
				Assert(writePtr + newsegsize <= PageGetSpecialPointer(page));
				memcpy(writePtr, newseg, newsegsize);
				writePtr += newsegsize;
				segptr += segsize;
				segno++;
				break;

			default:
				elog(ERROR, "unexpected GIN leaf action: %u", a_action);
		}
		oldseg = (GinPostingList *) segptr;
	}

	/* Copy the rest of unmodified segments if any. */
	segptr = (Pointer) oldseg;
	if (segptr != segmentend && tailCopy)
	{
		int restSize = segmentend - segptr;

		Assert(writePtr + restSize <= PageGetSpecialPointer(page));
		memcpy(writePtr, segptr, restSize);
		writePtr += restSize;
	}

	totalsize = writePtr - (Pointer) GinDataLeafPageGetPostingList(page);
	GinDataPageSetDataSize(page, totalsize);
}