Пример #1
0
/*
 * Move all tuples out of a page.
 *
 * The caller must hold lock on the page. The lock and pin are released.
 */
void
brin_evacuate_page(Relation idxRel, BlockNumber pagesPerRange,
				   BrinRevmap *revmap, Buffer buf)
{
	OffsetNumber off;
	OffsetNumber maxoff;
	Page		page;

	page = BufferGetPage(buf);

	Assert(((BrinSpecialSpace *)
			PageGetSpecialPointer(page))->flags & BRIN_EVACUATE_PAGE);

	maxoff = PageGetMaxOffsetNumber(page);
	for (off = FirstOffsetNumber; off <= maxoff; off++)
	{
		BrinTuple  *tup;
		Size		sz;
		ItemId		lp;

		CHECK_FOR_INTERRUPTS();

		lp = PageGetItemId(page, off);
		if (ItemIdIsUsed(lp))
		{
			sz = ItemIdGetLength(lp);
			tup = (BrinTuple *) PageGetItem(page, lp);
			tup = brin_copy_tuple(tup, sz);

			LockBuffer(buf, BUFFER_LOCK_UNLOCK);

			if (!brin_doupdate(idxRel, pagesPerRange, revmap, tup->bt_blkno,
							   buf, off, tup, sz, tup, sz, false))
				off--;			/* retry */

			LockBuffer(buf, BUFFER_LOCK_SHARE);

			/* It's possible that someone extended the revmap over this page */
			if (!BRIN_IS_REGULAR_PAGE(page))
				break;
		}
	}

	UnlockReleaseBuffer(buf);
}
Пример #2
0
/*
 * Summarize the given page range of the given index.
 *
 * This routine can run in parallel with insertions into the heap.  To avoid
 * missing those values from the summary tuple, we first insert a placeholder
 * index tuple into the index, then execute the heap scan; transactions
 * concurrent with the scan update the placeholder tuple.  After the scan, we
 * union the placeholder tuple with the one computed by this routine.  The
 * update of the index value happens in a loop, so that if somebody updates
 * the placeholder tuple after we read it, we detect the case and try again.
 * This ensures that the concurrently inserted tuples are not lost.
 */
static void
summarize_range(IndexInfo *indexInfo, BrinBuildState *state, Relation heapRel,
				BlockNumber heapBlk, BlockNumber heapNumBlks)
{
	Buffer		phbuf;
	BrinTuple  *phtup;
	Size		phsz;
	OffsetNumber offset;
	BlockNumber scanNumBlks;

	/*
	 * Insert the placeholder tuple
	 */
	phbuf = InvalidBuffer;
	phtup = brin_form_placeholder_tuple(state->bs_bdesc, heapBlk, &phsz);
	offset = brin_doinsert(state->bs_irel, state->bs_pagesPerRange,
						   state->bs_rmAccess, &phbuf,
						   heapBlk, phtup, phsz);

	/*
	 * Execute the partial heap scan covering the heap blocks in the specified
	 * page range, summarizing the heap tuples in it.  This scan stops just
	 * short of brinbuildCallback creating the new index entry.
	 *
	 * Note that it is critical we use the "any visible" mode of
	 * IndexBuildHeapRangeScan here: otherwise, we would miss tuples inserted
	 * by transactions that are still in progress, among other corner cases.
	 */
	state->bs_currRangeStart = heapBlk;
	scanNumBlks = heapBlk + state->bs_pagesPerRange <= heapNumBlks ?
		state->bs_pagesPerRange : heapNumBlks - heapBlk;
	IndexBuildHeapRangeScan(heapRel, state->bs_irel, indexInfo, false, true,
							heapBlk, scanNumBlks,
							brinbuildCallback, (void *) state);

	/*
	 * Now we update the values obtained by the scan with the placeholder
	 * tuple.  We do this in a loop which only terminates if we're able to
	 * update the placeholder tuple successfully; if we are not, this means
	 * somebody else modified the placeholder tuple after we read it.
	 */
	for (;;)
	{
		BrinTuple  *newtup;
		Size		newsize;
		bool		didupdate;
		bool		samepage;

		CHECK_FOR_INTERRUPTS();

		/*
		 * Update the summary tuple and try to update.
		 */
		newtup = brin_form_tuple(state->bs_bdesc,
								 heapBlk, state->bs_dtuple, &newsize);
		samepage = brin_can_do_samepage_update(phbuf, phsz, newsize);
		didupdate =
			brin_doupdate(state->bs_irel, state->bs_pagesPerRange,
						  state->bs_rmAccess, heapBlk, phbuf, offset,
						  phtup, phsz, newtup, newsize, samepage);
		brin_free_tuple(phtup);
		brin_free_tuple(newtup);

		/* If the update succeeded, we're done. */
		if (didupdate)
			break;

		/*
		 * If the update didn't work, it might be because somebody updated the
		 * placeholder tuple concurrently.  Extract the new version, union it
		 * with the values we have from the scan, and start over.  (There are
		 * other reasons for the update to fail, but it's simple to treat them
		 * the same.)
		 */
		phtup = brinGetTupleForHeapBlock(state->bs_rmAccess, heapBlk, &phbuf,
										 &offset, &phsz, BUFFER_LOCK_SHARE,
										 NULL);
		/* the placeholder tuple must exist */
		if (phtup == NULL)
			elog(ERROR, "missing placeholder tuple");
		phtup = brin_copy_tuple(phtup, phsz);
		LockBuffer(phbuf, BUFFER_LOCK_UNLOCK);

		/* merge it into the tuple from the heap scan */
		union_tuples(state->bs_bdesc, state->bs_dtuple, phtup);
	}

	ReleaseBuffer(phbuf);
}
Пример #3
0
/*
 * A tuple in the heap is being inserted.  To keep a brin index up to date,
 * we need to obtain the relevant index tuple and compare its stored values
 * with those of the new tuple.  If the tuple values are not consistent with
 * the summary tuple, we need to update the index tuple.
 *
 * If the range is not currently summarized (i.e. the revmap returns NULL for
 * it), there's nothing to do.
 */
bool
brininsert(Relation idxRel, Datum *values, bool *nulls,
		   ItemPointer heaptid, Relation heapRel,
		   IndexUniqueCheck checkUnique)
{
	BlockNumber pagesPerRange;
	BrinDesc   *bdesc = NULL;
	BrinRevmap *revmap;
	Buffer		buf = InvalidBuffer;
	MemoryContext tupcxt = NULL;
	MemoryContext oldcxt = NULL;

	revmap = brinRevmapInitialize(idxRel, &pagesPerRange, NULL);

	for (;;)
	{
		bool		need_insert = false;
		OffsetNumber off;
		BrinTuple  *brtup;
		BrinMemTuple *dtup;
		BlockNumber heapBlk;
		int			keyno;

		CHECK_FOR_INTERRUPTS();

		heapBlk = ItemPointerGetBlockNumber(heaptid);
		/* normalize the block number to be the first block in the range */
		heapBlk = (heapBlk / pagesPerRange) * pagesPerRange;
		brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off, NULL,
										 BUFFER_LOCK_SHARE, NULL);

		/* if range is unsummarized, there's nothing to do */
		if (!brtup)
			break;

		/* First time through? */
		if (bdesc == NULL)
		{
			bdesc = brin_build_desc(idxRel);
			tupcxt = AllocSetContextCreate(CurrentMemoryContext,
										   "brininsert cxt",
										   ALLOCSET_DEFAULT_SIZES);
			oldcxt = MemoryContextSwitchTo(tupcxt);
		}

		dtup = brin_deform_tuple(bdesc, brtup);

		/*
		 * Compare the key values of the new tuple to the stored index values;
		 * our deformed tuple will get updated if the new tuple doesn't fit
		 * the original range (note this means we can't break out of the loop
		 * early). Make a note of whether this happens, so that we know to
		 * insert the modified tuple later.
		 */
		for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
		{
			Datum		result;
			BrinValues *bval;
			FmgrInfo   *addValue;

			bval = &dtup->bt_columns[keyno];
			addValue = index_getprocinfo(idxRel, keyno + 1,
										 BRIN_PROCNUM_ADDVALUE);
			result = FunctionCall4Coll(addValue,
									   idxRel->rd_indcollation[keyno],
									   PointerGetDatum(bdesc),
									   PointerGetDatum(bval),
									   values[keyno],
									   nulls[keyno]);
			/* if that returned true, we need to insert the updated tuple */
			need_insert |= DatumGetBool(result);
		}

		if (!need_insert)
		{
			/*
			 * The tuple is consistent with the new values, so there's nothing
			 * to do.
			 */
			LockBuffer(buf, BUFFER_LOCK_UNLOCK);
		}
		else
		{
			Page		page = BufferGetPage(buf);
			ItemId		lp = PageGetItemId(page, off);
			Size		origsz;
			BrinTuple  *origtup;
			Size		newsz;
			BrinTuple  *newtup;
			bool		samepage;

			/*
			 * Make a copy of the old tuple, so that we can compare it after
			 * re-acquiring the lock.
			 */
			origsz = ItemIdGetLength(lp);
			origtup = brin_copy_tuple(brtup, origsz);

			/*
			 * Before releasing the lock, check if we can attempt a same-page
			 * update.  Another process could insert a tuple concurrently in
			 * the same page though, so downstream we must be prepared to cope
			 * if this turns out to not be possible after all.
			 */
			newtup = brin_form_tuple(bdesc, heapBlk, dtup, &newsz);
			samepage = brin_can_do_samepage_update(buf, origsz, newsz);
			LockBuffer(buf, BUFFER_LOCK_UNLOCK);

			/*
			 * Try to update the tuple.  If this doesn't work for whatever
			 * reason, we need to restart from the top; the revmap might be
			 * pointing at a different tuple for this block now, so we need to
			 * recompute to ensure both our new heap tuple and the other
			 * inserter's are covered by the combined tuple.  It might be that
			 * we don't need to update at all.
			 */
			if (!brin_doupdate(idxRel, pagesPerRange, revmap, heapBlk,
							   buf, off, origtup, origsz, newtup, newsz,
							   samepage))
			{
				/* no luck; start over */
				MemoryContextResetAndDeleteChildren(tupcxt);
				continue;
			}
		}

		/* success! */
		break;
	}

	brinRevmapTerminate(revmap);
	if (BufferIsValid(buf))
		ReleaseBuffer(buf);
	if (bdesc != NULL)
	{
		brin_free_desc(bdesc);
		MemoryContextSwitchTo(oldcxt);
		MemoryContextDelete(tupcxt);
	}

	return false;
}
Пример #4
0
/*
 * On the given BRIN index, summarize the heap page range that corresponds
 * to the heap block number given.
 *
 * This routine can run in parallel with insertions into the heap.  To avoid
 * missing those values from the summary tuple, we first insert a placeholder
 * index tuple into the index, then execute the heap scan; transactions
 * concurrent with the scan update the placeholder tuple.  After the scan, we
 * union the placeholder tuple with the one computed by this routine.  The
 * update of the index value happens in a loop, so that if somebody updates
 * the placeholder tuple after we read it, we detect the case and try again.
 * This ensures that the concurrently inserted tuples are not lost.
 *
 * A further corner case is this routine being asked to summarize the partial
 * range at the end of the table.  heapNumBlocks is the (possibly outdated)
 * table size; if we notice that the requested range lies beyond that size,
 * we re-compute the table size after inserting the placeholder tuple, to
 * avoid missing pages that were appended recently.
 */
static void
summarize_range(IndexInfo *indexInfo, BrinBuildState *state, Relation heapRel,
				BlockNumber heapBlk, BlockNumber heapNumBlks)
{
	Buffer		phbuf;
	BrinTuple  *phtup;
	Size		phsz;
	OffsetNumber offset;
	BlockNumber scanNumBlks;

	/*
	 * Insert the placeholder tuple
	 */
	phbuf = InvalidBuffer;
	phtup = brin_form_placeholder_tuple(state->bs_bdesc, heapBlk, &phsz);
	offset = brin_doinsert(state->bs_irel, state->bs_pagesPerRange,
						   state->bs_rmAccess, &phbuf,
						   heapBlk, phtup, phsz);

	/*
	 * Compute range end.  We hold ShareUpdateExclusive lock on table, so it
	 * cannot shrink concurrently (but it can grow).
	 */
	Assert(heapBlk % state->bs_pagesPerRange == 0);
	if (heapBlk + state->bs_pagesPerRange > heapNumBlks)
	{
		/*
		 * If we're asked to scan what we believe to be the final range on the
		 * table (i.e. a range that might be partial) we need to recompute our
		 * idea of what the latest page is after inserting the placeholder
		 * tuple.  Anyone that grows the table later will update the
		 * placeholder tuple, so it doesn't matter that we won't scan these
		 * pages ourselves.  Careful: the table might have been extended
		 * beyond the current range, so clamp our result.
		 *
		 * Fortunately, this should occur infrequently.
		 */
		scanNumBlks = Min(RelationGetNumberOfBlocks(heapRel) - heapBlk,
						  state->bs_pagesPerRange);
	}
	else
	{
		/* Easy case: range is known to be complete */
		scanNumBlks = state->bs_pagesPerRange;
	}

	/*
	 * Execute the partial heap scan covering the heap blocks in the specified
	 * page range, summarizing the heap tuples in it.  This scan stops just
	 * short of brinbuildCallback creating the new index entry.
	 *
	 * Note that it is critical we use the "any visible" mode of
	 * IndexBuildHeapRangeScan here: otherwise, we would miss tuples inserted
	 * by transactions that are still in progress, among other corner cases.
	 */
	state->bs_currRangeStart = heapBlk;
	IndexBuildHeapRangeScan(heapRel, state->bs_irel, indexInfo, false, true,
							heapBlk, scanNumBlks,
							brinbuildCallback, (void *) state);

	/*
	 * Now we update the values obtained by the scan with the placeholder
	 * tuple.  We do this in a loop which only terminates if we're able to
	 * update the placeholder tuple successfully; if we are not, this means
	 * somebody else modified the placeholder tuple after we read it.
	 */
	for (;;)
	{
		BrinTuple  *newtup;
		Size		newsize;
		bool		didupdate;
		bool		samepage;

		CHECK_FOR_INTERRUPTS();

		/*
		 * Update the summary tuple and try to update.
		 */
		newtup = brin_form_tuple(state->bs_bdesc,
								 heapBlk, state->bs_dtuple, &newsize);
		samepage = brin_can_do_samepage_update(phbuf, phsz, newsize);
		didupdate =
			brin_doupdate(state->bs_irel, state->bs_pagesPerRange,
						  state->bs_rmAccess, heapBlk, phbuf, offset,
						  phtup, phsz, newtup, newsize, samepage);
		brin_free_tuple(phtup);
		brin_free_tuple(newtup);

		/* If the update succeeded, we're done. */
		if (didupdate)
			break;

		/*
		 * If the update didn't work, it might be because somebody updated the
		 * placeholder tuple concurrently.  Extract the new version, union it
		 * with the values we have from the scan, and start over.  (There are
		 * other reasons for the update to fail, but it's simple to treat them
		 * the same.)
		 */
		phtup = brinGetTupleForHeapBlock(state->bs_rmAccess, heapBlk, &phbuf,
										 &offset, &phsz, BUFFER_LOCK_SHARE,
										 NULL);
		/* the placeholder tuple must exist */
		if (phtup == NULL)
			elog(ERROR, "missing placeholder tuple");
		phtup = brin_copy_tuple(phtup, phsz);
		LockBuffer(phbuf, BUFFER_LOCK_UNLOCK);

		/* merge it into the tuple from the heap scan */
		union_tuples(state->bs_bdesc, state->bs_dtuple, phtup);
	}

	ReleaseBuffer(phbuf);
}
Пример #5
0
/*
 * A tuple in the heap is being inserted.  To keep a brin index up to date,
 * we need to obtain the relevant index tuple and compare its stored values
 * with those of the new tuple.  If the tuple values are not consistent with
 * the summary tuple, we need to update the index tuple.
 *
 * If the range is not currently summarized (i.e. the revmap returns NULL for
 * it), there's nothing to do.
 */
Datum
brininsert(PG_FUNCTION_ARGS)
{
	Relation	idxRel = (Relation) PG_GETARG_POINTER(0);
	Datum	   *values = (Datum *) PG_GETARG_POINTER(1);
	bool	   *nulls = (bool *) PG_GETARG_POINTER(2);
	ItemPointer heaptid = (ItemPointer) PG_GETARG_POINTER(3);

	/* we ignore the rest of our arguments */
	BlockNumber pagesPerRange;
	BrinDesc   *bdesc = NULL;
	BrinRevmap *revmap;
	Buffer		buf = InvalidBuffer;
	MemoryContext tupcxt = NULL;
	MemoryContext oldcxt = NULL;

	revmap = brinRevmapInitialize(idxRel, &pagesPerRange);

	for (;;)
	{
		bool		need_insert = false;
		OffsetNumber off;
		BrinTuple  *brtup;
		BrinMemTuple *dtup;
		BlockNumber heapBlk;
		int			keyno;
#ifdef USE_ASSERT_CHECKING
		BrinTuple  *tmptup;
		BrinMemTuple *tmpdtup;
		Size 		tmpsiz;
#endif

		CHECK_FOR_INTERRUPTS();

		heapBlk = ItemPointerGetBlockNumber(heaptid);
		/* normalize the block number to be the first block in the range */
		heapBlk = (heapBlk / pagesPerRange) * pagesPerRange;
		brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off, NULL,
										 BUFFER_LOCK_SHARE);

		/* if range is unsummarized, there's nothing to do */
		if (!brtup)
			break;

		/* First time through? */
		if (bdesc == NULL)
		{
			bdesc = brin_build_desc(idxRel);
			tupcxt = AllocSetContextCreate(CurrentMemoryContext,
										   "brininsert cxt",
										   ALLOCSET_DEFAULT_MINSIZE,
										   ALLOCSET_DEFAULT_INITSIZE,
										   ALLOCSET_DEFAULT_MAXSIZE);
			oldcxt = MemoryContextSwitchTo(tupcxt);
		}

		dtup = brin_deform_tuple(bdesc, brtup);

#ifdef USE_ASSERT_CHECKING
		{
			/*
			 * When assertions are enabled, we use this as an opportunity to
			 * test the "union" method, which would otherwise be used very
			 * rarely: first create a placeholder tuple, and addValue the
			 * value we just got into it.  Then union the existing index tuple
			 * with the updated placeholder tuple.  The tuple resulting from
			 * that union should be identical to the one resulting from the
			 * regular operation (straight addValue) below.
			 *
			 * Here we create the tuple to compare with; the actual comparison
			 * is below.
			 */
			tmptup = brin_form_placeholder_tuple(bdesc, heapBlk, &tmpsiz);
			tmpdtup = brin_deform_tuple(bdesc, tmptup);
			for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
			{
				BrinValues *bval;
				FmgrInfo   *addValue;

				bval = &tmpdtup->bt_columns[keyno];
				addValue = index_getprocinfo(idxRel, keyno + 1,
											 BRIN_PROCNUM_ADDVALUE);
				FunctionCall4Coll(addValue,
								  idxRel->rd_indcollation[keyno],
								  PointerGetDatum(bdesc),
								  PointerGetDatum(bval),
								  values[keyno],
								  nulls[keyno]);
			}

			union_tuples(bdesc, tmpdtup, brtup);

			tmpdtup->bt_placeholder = dtup->bt_placeholder;
			tmptup = brin_form_tuple(bdesc, heapBlk, tmpdtup, &tmpsiz);
		}
#endif

		/*
		 * Compare the key values of the new tuple to the stored index values;
		 * our deformed tuple will get updated if the new tuple doesn't fit
		 * the original range (note this means we can't break out of the loop
		 * early). Make a note of whether this happens, so that we know to
		 * insert the modified tuple later.
		 */
		for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
		{
			Datum		result;
			BrinValues *bval;
			FmgrInfo   *addValue;

			bval = &dtup->bt_columns[keyno];
			addValue = index_getprocinfo(idxRel, keyno + 1,
										 BRIN_PROCNUM_ADDVALUE);
			result = FunctionCall4Coll(addValue,
									   idxRel->rd_indcollation[keyno],
									   PointerGetDatum(bdesc),
									   PointerGetDatum(bval),
									   values[keyno],
									   nulls[keyno]);
			/* if that returned true, we need to insert the updated tuple */
			need_insert |= DatumGetBool(result);
		}

#ifdef USE_ASSERT_CHECKING
		{
			/*
			 * Now we can compare the tuple produced by the union function
			 * with the one from plain addValue.
			 */
			BrinTuple  *cmptup;
			Size		cmpsz;

			cmptup = brin_form_tuple(bdesc, heapBlk, dtup, &cmpsz);
			Assert(brin_tuples_equal(tmptup, tmpsiz, cmptup, cmpsz));
		}
#endif

		if (!need_insert)
		{
			/*
			 * The tuple is consistent with the new values, so there's nothing
			 * to do.
			 */
			LockBuffer(buf, BUFFER_LOCK_UNLOCK);
		}
		else
		{
			Page		page = BufferGetPage(buf);
			ItemId		lp = PageGetItemId(page, off);
			Size		origsz;
			BrinTuple  *origtup;
			Size		newsz;
			BrinTuple  *newtup;
			bool		samepage;

			/*
			 * Make a copy of the old tuple, so that we can compare it after
			 * re-acquiring the lock.
			 */
			origsz = ItemIdGetLength(lp);
			origtup = brin_copy_tuple(brtup, origsz);

			/*
			 * Before releasing the lock, check if we can attempt a same-page
			 * update.  Another process could insert a tuple concurrently in
			 * the same page though, so downstream we must be prepared to cope
			 * if this turns out to not be possible after all.
			 */
			newtup = brin_form_tuple(bdesc, heapBlk, dtup, &newsz);
			samepage = brin_can_do_samepage_update(buf, origsz, newsz);
			LockBuffer(buf, BUFFER_LOCK_UNLOCK);

			/*
			 * Try to update the tuple.  If this doesn't work for whatever
			 * reason, we need to restart from the top; the revmap might be
			 * pointing at a different tuple for this block now, so we need to
			 * recompute to ensure both our new heap tuple and the other
			 * inserter's are covered by the combined tuple.  It might be that
			 * we don't need to update at all.
			 */
			if (!brin_doupdate(idxRel, pagesPerRange, revmap, heapBlk,
							   buf, off, origtup, origsz, newtup, newsz,
							   samepage))
			{
				/* no luck; start over */
				MemoryContextResetAndDeleteChildren(tupcxt);
				continue;
			}
		}

		/* success! */
		break;
	}

	brinRevmapTerminate(revmap);
	if (BufferIsValid(buf))
		ReleaseBuffer(buf);
	if (bdesc != NULL)
	{
		brin_free_desc(bdesc);
		MemoryContextSwitchTo(oldcxt);
		MemoryContextDelete(tupcxt);
	}

	return BoolGetDatum(false);
}
Пример #6
0
/*
 * A tuple in the heap is being inserted.  To keep a brin index up to date,
 * we need to obtain the relevant index tuple and compare its stored values
 * with those of the new tuple.  If the tuple values are not consistent with
 * the summary tuple, we need to update the index tuple.
 *
 * If autosummarization is enabled, check if we need to summarize the previous
 * page range.
 *
 * If the range is not currently summarized (i.e. the revmap returns NULL for
 * it), there's nothing to do for this tuple.
 */
bool
brininsert(Relation idxRel, Datum *values, bool *nulls,
		   ItemPointer heaptid, Relation heapRel,
		   IndexUniqueCheck checkUnique,
		   IndexInfo *indexInfo)
{
	BlockNumber pagesPerRange;
	BlockNumber origHeapBlk;
	BlockNumber heapBlk;
	BrinDesc   *bdesc = (BrinDesc *) indexInfo->ii_AmCache;
	BrinRevmap *revmap;
	Buffer		buf = InvalidBuffer;
	MemoryContext tupcxt = NULL;
	MemoryContext oldcxt = CurrentMemoryContext;
	bool		autosummarize = BrinGetAutoSummarize(idxRel);

	revmap = brinRevmapInitialize(idxRel, &pagesPerRange, NULL);

	/*
	 * origHeapBlk is the block number where the insertion occurred.  heapBlk
	 * is the first block in the corresponding page range.
	 */
	origHeapBlk = ItemPointerGetBlockNumber(heaptid);
	heapBlk = (origHeapBlk / pagesPerRange) * pagesPerRange;

	for (;;)
	{
		bool		need_insert = false;
		OffsetNumber off;
		BrinTuple  *brtup;
		BrinMemTuple *dtup;
		int			keyno;

		CHECK_FOR_INTERRUPTS();

		/*
		 * If auto-summarization is enabled and we just inserted the first
		 * tuple into the first block of a new non-first page range, request a
		 * summarization run of the previous range.
		 */
		if (autosummarize &&
			heapBlk > 0 &&
			heapBlk == origHeapBlk &&
			ItemPointerGetOffsetNumber(heaptid) == FirstOffsetNumber)
		{
			BlockNumber lastPageRange = heapBlk - 1;
			BrinTuple  *lastPageTuple;

			lastPageTuple =
				brinGetTupleForHeapBlock(revmap, lastPageRange, &buf, &off,
										 NULL, BUFFER_LOCK_SHARE, NULL);
			if (!lastPageTuple)
			{
				bool		recorded;

				recorded = AutoVacuumRequestWork(AVW_BRINSummarizeRange,
												 RelationGetRelid(idxRel),
												 lastPageRange);
				if (!recorded)
					ereport(LOG,
							(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
							 errmsg("request for BRIN range summarization for index \"%s\" page %u was not recorded",
									RelationGetRelationName(idxRel),
									lastPageRange)));
			}
			else
				LockBuffer(buf, BUFFER_LOCK_UNLOCK);
		}

		brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off,
										 NULL, BUFFER_LOCK_SHARE, NULL);

		/* if range is unsummarized, there's nothing to do */
		if (!brtup)
			break;

		/* First time through in this statement? */
		if (bdesc == NULL)
		{
			MemoryContextSwitchTo(indexInfo->ii_Context);
			bdesc = brin_build_desc(idxRel);
			indexInfo->ii_AmCache = (void *) bdesc;
			MemoryContextSwitchTo(oldcxt);
		}
		/* First time through in this brininsert call? */
		if (tupcxt == NULL)
		{
			tupcxt = AllocSetContextCreate(CurrentMemoryContext,
										   "brininsert cxt",
										   ALLOCSET_DEFAULT_SIZES);
			MemoryContextSwitchTo(tupcxt);
		}

		dtup = brin_deform_tuple(bdesc, brtup, NULL);

		/*
		 * Compare the key values of the new tuple to the stored index values;
		 * our deformed tuple will get updated if the new tuple doesn't fit
		 * the original range (note this means we can't break out of the loop
		 * early). Make a note of whether this happens, so that we know to
		 * insert the modified tuple later.
		 */
		for (keyno = 0; keyno < bdesc->bd_tupdesc->natts; keyno++)
		{
			Datum		result;
			BrinValues *bval;
			FmgrInfo   *addValue;

			bval = &dtup->bt_columns[keyno];
			addValue = index_getprocinfo(idxRel, keyno + 1,
										 BRIN_PROCNUM_ADDVALUE);
			result = FunctionCall4Coll(addValue,
									   idxRel->rd_indcollation[keyno],
									   PointerGetDatum(bdesc),
									   PointerGetDatum(bval),
									   values[keyno],
									   nulls[keyno]);
			/* if that returned true, we need to insert the updated tuple */
			need_insert |= DatumGetBool(result);
		}

		if (!need_insert)
		{
			/*
			 * The tuple is consistent with the new values, so there's nothing
			 * to do.
			 */
			LockBuffer(buf, BUFFER_LOCK_UNLOCK);
		}
		else
		{
			Page		page = BufferGetPage(buf);
			ItemId		lp = PageGetItemId(page, off);
			Size		origsz;
			BrinTuple  *origtup;
			Size		newsz;
			BrinTuple  *newtup;
			bool		samepage;

			/*
			 * Make a copy of the old tuple, so that we can compare it after
			 * re-acquiring the lock.
			 */
			origsz = ItemIdGetLength(lp);
			origtup = brin_copy_tuple(brtup, origsz, NULL, NULL);

			/*
			 * Before releasing the lock, check if we can attempt a same-page
			 * update.  Another process could insert a tuple concurrently in
			 * the same page though, so downstream we must be prepared to cope
			 * if this turns out to not be possible after all.
			 */
			newtup = brin_form_tuple(bdesc, heapBlk, dtup, &newsz);
			samepage = brin_can_do_samepage_update(buf, origsz, newsz);
			LockBuffer(buf, BUFFER_LOCK_UNLOCK);

			/*
			 * Try to update the tuple.  If this doesn't work for whatever
			 * reason, we need to restart from the top; the revmap might be
			 * pointing at a different tuple for this block now, so we need to
			 * recompute to ensure both our new heap tuple and the other
			 * inserter's are covered by the combined tuple.  It might be that
			 * we don't need to update at all.
			 */
			if (!brin_doupdate(idxRel, pagesPerRange, revmap, heapBlk,
							   buf, off, origtup, origsz, newtup, newsz,
							   samepage))
			{
				/* no luck; start over */
				MemoryContextResetAndDeleteChildren(tupcxt);
				continue;
			}
		}

		/* success! */
		break;
	}

	brinRevmapTerminate(revmap);
	if (BufferIsValid(buf))
		ReleaseBuffer(buf);
	MemoryContextSwitchTo(oldcxt);
	if (tupcxt != NULL)
		MemoryContextDelete(tupcxt);

	return false;
}