Example #1
0
/*
 *	PageAddItem
 *
 *	Add an item to a page.  Return value is offset at which it was
 *	inserted, or InvalidOffsetNumber if the item is not inserted for
 *	any reason.
 *
 *	Passing the 'overwrite' and 'is_heap' parameters as true causes the
 *	PAI_OVERWRITE and PAI_IS_HEAP flags to be set, respectively.
 *
 *	!!! EREPORT(ERROR) IS DISALLOWED HERE !!!
 */
OffsetNumber
PageAddItem(Page page, Item item, Size size, OffsetNumber offsetNumber,
			bool overwrite, bool is_heap)
{
	return PageAddItemExtended(page, item, size, offsetNumber,
							   overwrite ? PAI_OVERWRITE : 0 |
							   is_heap ? PAI_IS_HEAP : 0);
}
Example #2
0
/*
 * Update tuple origtup (size origsz), located in offset oldoff of buffer
 * oldbuf, to newtup (size newsz) as summary tuple for the page range starting
 * at heapBlk.  oldbuf must not be locked on entry, and is not locked at exit.
 *
 * If samepage is true, attempt to put the new tuple in the same page, but if
 * there's no room, use some other one.
 *
 * If the update is successful, return true; the revmap is updated to point to
 * the new tuple.  If the update is not done for whatever reason, return false.
 * Caller may retry the update if this happens.
 */
bool
brin_doupdate(Relation idxrel, BlockNumber pagesPerRange,
			  BrinRevmap *revmap, BlockNumber heapBlk,
			  Buffer oldbuf, OffsetNumber oldoff,
			  const BrinTuple *origtup, Size origsz,
			  const BrinTuple *newtup, Size newsz,
			  bool samepage)
{
	Page		oldpage;
	ItemId		oldlp;
	BrinTuple  *oldtup;
	Size		oldsz;
	Buffer		newbuf;
	bool		extended;

	Assert(newsz == MAXALIGN(newsz));

	/* If the item is oversized, don't bother. */
	if (newsz > BrinMaxItemSize)
	{
		ereport(ERROR,
				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
			errmsg("index row size %lu exceeds maximum %lu for index \"%s\"",
				   (unsigned long) newsz,
				   (unsigned long) BrinMaxItemSize,
				   RelationGetRelationName(idxrel))));
		return false;			/* keep compiler quiet */
	}

	/* make sure the revmap is long enough to contain the entry we need */
	brinRevmapExtend(revmap, heapBlk);

	if (!samepage)
	{
		/* need a page on which to put the item */
		newbuf = brin_getinsertbuffer(idxrel, oldbuf, newsz, &extended);
		if (!BufferIsValid(newbuf))
		{
			Assert(!extended);
			return false;
		}

		/*
		 * Note: it's possible (though unlikely) that the returned newbuf is
		 * the same as oldbuf, if brin_getinsertbuffer determined that the old
		 * buffer does in fact have enough space.
		 */
		if (newbuf == oldbuf)
		{
			Assert(!extended);
			newbuf = InvalidBuffer;
		}
	}
	else
	{
		LockBuffer(oldbuf, BUFFER_LOCK_EXCLUSIVE);
		newbuf = InvalidBuffer;
		extended = false;
	}
	oldpage = BufferGetPage(oldbuf);
	oldlp = PageGetItemId(oldpage, oldoff);

	/*
	 * Check that the old tuple wasn't updated concurrently: it might have
	 * moved someplace else entirely ...
	 */
	if (!ItemIdIsNormal(oldlp))
	{
		LockBuffer(oldbuf, BUFFER_LOCK_UNLOCK);

		/*
		 * If this happens, and the new buffer was obtained by extending the
		 * relation, then we need to ensure we don't leave it uninitialized or
		 * forget about it.
		 */
		if (BufferIsValid(newbuf))
		{
			if (extended)
				brin_initialize_empty_new_buffer(idxrel, newbuf);
			UnlockReleaseBuffer(newbuf);
			if (extended)
				FreeSpaceMapVacuum(idxrel);
		}
		return false;
	}

	oldsz = ItemIdGetLength(oldlp);
	oldtup = (BrinTuple *) PageGetItem(oldpage, oldlp);

	/*
	 * ... or it might have been updated in place to different contents.
	 */
	if (!brin_tuples_equal(oldtup, oldsz, origtup, origsz))
	{
		LockBuffer(oldbuf, BUFFER_LOCK_UNLOCK);
		if (BufferIsValid(newbuf))
		{
			if (extended)
				brin_initialize_empty_new_buffer(idxrel, newbuf);
			UnlockReleaseBuffer(newbuf);
			if (extended)
				FreeSpaceMapVacuum(idxrel);
		}
		return false;
	}

	/*
	 * Great, the old tuple is intact.  We can proceed with the update.
	 *
	 * If there's enough room in the old page for the new tuple, replace it.
	 *
	 * Note that there might now be enough space on the page even though the
	 * caller told us there isn't, if a concurrent update moved another tuple
	 * elsewhere or replaced a tuple with a smaller one.
	 */
	if (((BrinPageFlags(oldpage) & BRIN_EVACUATE_PAGE) == 0) &&
		brin_can_do_samepage_update(oldbuf, origsz, newsz))
	{
		if (BufferIsValid(newbuf))
		{
			/* as above */
			if (extended)
				brin_initialize_empty_new_buffer(idxrel, newbuf);
			UnlockReleaseBuffer(newbuf);
		}

		START_CRIT_SECTION();
		PageIndexDeleteNoCompact(oldpage, &oldoff, 1);
		if (PageAddItemExtended(oldpage, (Item) newtup, newsz, oldoff,
				PAI_OVERWRITE | PAI_ALLOW_FAR_OFFSET) == InvalidOffsetNumber)
			elog(ERROR, "failed to add BRIN tuple");
		MarkBufferDirty(oldbuf);

		/* XLOG stuff */
		if (RelationNeedsWAL(idxrel))
		{
			xl_brin_samepage_update xlrec;
			XLogRecPtr	recptr;
			uint8		info = XLOG_BRIN_SAMEPAGE_UPDATE;

			xlrec.offnum = oldoff;

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

			XLogRegisterBuffer(0, oldbuf, REGBUF_STANDARD);
			XLogRegisterBufData(0, (char *) newtup, newsz);

			recptr = XLogInsert(RM_BRIN_ID, info);

			PageSetLSN(oldpage, recptr);
		}

		END_CRIT_SECTION();

		LockBuffer(oldbuf, BUFFER_LOCK_UNLOCK);

		if (extended)
			FreeSpaceMapVacuum(idxrel);

		return true;
	}
	else if (newbuf == InvalidBuffer)
	{
		/*
		 * Not enough space, but caller said that there was. Tell them to
		 * start over.
		 */
		LockBuffer(oldbuf, BUFFER_LOCK_UNLOCK);
		return false;
	}
	else
	{
		/*
		 * Not enough free space on the oldpage. Put the new tuple on the new
		 * page, and update the revmap.
		 */
		Page		newpage = BufferGetPage(newbuf);
		Buffer		revmapbuf;
		ItemPointerData newtid;
		OffsetNumber newoff;
		BlockNumber newblk = InvalidBlockNumber;
		Size		freespace = 0;

		revmapbuf = brinLockRevmapPageForUpdate(revmap, heapBlk);

		START_CRIT_SECTION();

		/*
		 * We need to initialize the page if it's newly obtained.  Note we
		 * will WAL-log the initialization as part of the update, so we don't
		 * need to do that here.
		 */
		if (extended)
			brin_page_init(BufferGetPage(newbuf), BRIN_PAGETYPE_REGULAR);

		PageIndexDeleteNoCompact(oldpage, &oldoff, 1);
		newoff = PageAddItem(newpage, (Item) newtup, newsz,
							 InvalidOffsetNumber, false, false);
		if (newoff == InvalidOffsetNumber)
			elog(ERROR, "failed to add BRIN tuple to new page");
		MarkBufferDirty(oldbuf);
		MarkBufferDirty(newbuf);

		/* needed to update FSM below */
		if (extended)
		{
			newblk = BufferGetBlockNumber(newbuf);
			freespace = br_page_get_freespace(newpage);
		}

		ItemPointerSet(&newtid, BufferGetBlockNumber(newbuf), newoff);
		brinSetHeapBlockItemptr(revmapbuf, pagesPerRange, heapBlk, newtid);
		MarkBufferDirty(revmapbuf);

		/* XLOG stuff */
		if (RelationNeedsWAL(idxrel))
		{
			xl_brin_update xlrec;
			XLogRecPtr	recptr;
			uint8		info;

			info = XLOG_BRIN_UPDATE | (extended ? XLOG_BRIN_INIT_PAGE : 0);

			xlrec.insert.offnum = newoff;
			xlrec.insert.heapBlk = heapBlk;
			xlrec.insert.pagesPerRange = pagesPerRange;
			xlrec.oldOffnum = oldoff;

			XLogBeginInsert();

			/* new page */
			XLogRegisterData((char *) &xlrec, SizeOfBrinUpdate);

			XLogRegisterBuffer(0, newbuf, REGBUF_STANDARD | (extended ? REGBUF_WILL_INIT : 0));
			XLogRegisterBufData(0, (char *) newtup, newsz);

			/* revmap page */
			XLogRegisterBuffer(1, revmapbuf, REGBUF_STANDARD);

			/* old page */
			XLogRegisterBuffer(2, oldbuf, REGBUF_STANDARD);

			recptr = XLogInsert(RM_BRIN_ID, info);

			PageSetLSN(oldpage, recptr);
			PageSetLSN(newpage, recptr);
			PageSetLSN(BufferGetPage(revmapbuf), recptr);
		}

		END_CRIT_SECTION();

		LockBuffer(revmapbuf, BUFFER_LOCK_UNLOCK);
		LockBuffer(oldbuf, BUFFER_LOCK_UNLOCK);
		UnlockReleaseBuffer(newbuf);

		if (extended)
		{
			Assert(BlockNumberIsValid(newblk));
			RecordPageWithFreeSpace(idxrel, newblk, freespace);
			FreeSpaceMapVacuum(idxrel);
		}

		return true;
	}
}