Refactor nbtree insertion scankeys.

Use dedicated struct to represent nbtree insertion scan keys.  Having a
dedicated struct makes the difference between search type scankeys and
insertion scankeys a lot clearer, and simplifies the signature of
several related functions.  This is based on a suggestion by Andrey
Lepikhov.

Streamline how unique index insertions cache binary search progress.
Cache the state of in-progress binary searches within _bt_check_unique()
for later instead of having callers avoid repeating the binary search in
an ad-hoc manner.  This makes it easy to add a new optimization:
_bt_check_unique() now falls out of its loop immediately in the common
case where it's already clear that there couldn't possibly be a
duplicate.

The new _bt_check_unique() scheme makes it a lot easier to manage cached
binary search effort afterwards, from within _bt_findinsertloc().  This
is needed for the upcoming patch to make nbtree tuples unique by
treating heap TID as a final tiebreaker column.  Unique key binary
searches need to restore lower and upper bounds.  They cannot simply
continue to use the >= lower bound as the offset to insert at, because
the heap TID tiebreaker column must be used in comparisons for the
restored binary search (unlike the original _bt_check_unique() binary
search, where scankey's heap TID column must be omitted).

Author: Peter Geoghegan, Heikki Linnakangas
Reviewed-By: Heikki Linnakangas, Andrey Lepikhov
Discussion: https://postgr.es/m/CAH2-WzmE6AhUdk9NdWBf4K3HjWXZBX3+umC7mH7+WDrKcRtsOw@mail.gmail.com

contrib/amcheck/verify_nbtree.c

@@ -127,9 +127,9 @@ static void bt_check_every_level(Relation rel, Relation heaprel,
 static BtreeLevel bt_check_level_from_leftmost(BtreeCheckState *state,
 							 BtreeLevel level);
 static void bt_target_page_check(BtreeCheckState *state);
-static ScanKey bt_right_page_check_scankey(BtreeCheckState *state);
-static void bt_downlink_check(BtreeCheckState *state, BlockNumber childblock,
-				  ScanKey targetkey);
+static BTScanInsert bt_right_page_check_scankey(BtreeCheckState *state);
+static void bt_downlink_check(BtreeCheckState *state, BTScanInsert targetkey,
+				  BlockNumber childblock);
 static void bt_downlink_missing_check(BtreeCheckState *state);
 static void bt_tuple_present_callback(Relation index, HeapTuple htup,
 						  Datum *values, bool *isnull,
@@ -139,14 +139,14 @@ static IndexTuple bt_normalize_tuple(BtreeCheckState *state,
 static inline bool offset_is_negative_infinity(BTPageOpaque opaque,
 							OffsetNumber offset);
 static inline bool invariant_leq_offset(BtreeCheckState *state,
-					 ScanKey key,
+					 BTScanInsert key,
 					 OffsetNumber upperbound);
 static inline bool invariant_geq_offset(BtreeCheckState *state,
-					 ScanKey key,
+					 BTScanInsert key,
 					 OffsetNumber lowerbound);
 static inline bool invariant_leq_nontarget_offset(BtreeCheckState *state,
-							   Page other,
-							   ScanKey key,
+							   BTScanInsert key,
+							   Page nontarget,
 							   OffsetNumber upperbound);
 static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum);
 
@@ -838,8 +838,8 @@ bt_target_page_check(BtreeCheckState *state)
 	{
 		ItemId		itemid;
 		IndexTuple	itup;
-		ScanKey		skey;
 		size_t		tupsize;
+		BTScanInsert skey;
 
 		CHECK_FOR_INTERRUPTS();
 
@@ -1030,7 +1030,7 @@ bt_target_page_check(BtreeCheckState *state)
 		 */
 		else if (offset == max)
 		{
-			ScanKey		rightkey;
+			BTScanInsert	rightkey;
 
 			/* Get item in next/right page */
 			rightkey = bt_right_page_check_scankey(state);
@@ -1082,7 +1082,7 @@ bt_target_page_check(BtreeCheckState *state)
 		{
 			BlockNumber childblock = BTreeInnerTupleGetDownLink(itup);
 
-			bt_downlink_check(state, childblock, skey);
+			bt_downlink_check(state, skey, childblock);
 		}
 	}
 
@@ -1111,11 +1111,12 @@ bt_target_page_check(BtreeCheckState *state)
  * Note that !readonly callers must reverify that target page has not
  * been concurrently deleted.
  */
-static ScanKey
+static BTScanInsert
 bt_right_page_check_scankey(BtreeCheckState *state)
 {
 	BTPageOpaque opaque;
 	ItemId		rightitem;
+	IndexTuple	firstitup;
 	BlockNumber targetnext;
 	Page		rightpage;
 	OffsetNumber nline;
@@ -1303,8 +1304,8 @@ bt_right_page_check_scankey(BtreeCheckState *state)
 	 * Return first real item scankey.  Note that this relies on right page
 	 * memory remaining allocated.
 	 */
-	return _bt_mkscankey(state->rel,
-						 (IndexTuple) PageGetItem(rightpage, rightitem));
+	firstitup = (IndexTuple) PageGetItem(rightpage, rightitem);
+	return _bt_mkscankey(state->rel, firstitup);
 }
 
 /*
@@ -1317,8 +1318,8 @@ bt_right_page_check_scankey(BtreeCheckState *state)
  * verification this way around is much more practical.
  */
 static void
-bt_downlink_check(BtreeCheckState *state, BlockNumber childblock,
-				  ScanKey targetkey)
+bt_downlink_check(BtreeCheckState *state, BTScanInsert targetkey,
+				  BlockNumber childblock)
 {
 	OffsetNumber offset;
 	OffsetNumber maxoffset;
@@ -1423,8 +1424,7 @@ bt_downlink_check(BtreeCheckState *state, BlockNumber childblock,
 		if (offset_is_negative_infinity(copaque, offset))
 			continue;
 
-		if (!invariant_leq_nontarget_offset(state, child,
-											targetkey, offset))
+		if (!invariant_leq_nontarget_offset(state, targetkey, child, offset))
 			ereport(ERROR,
 					(errcode(ERRCODE_INDEX_CORRUPTED),
 					 errmsg("down-link lower bound invariant violated for index \"%s\"",
@@ -1864,13 +1864,12 @@ offset_is_negative_infinity(BTPageOpaque opaque, OffsetNumber offset)
  * to corruption.
  */
 static inline bool
-invariant_leq_offset(BtreeCheckState *state, ScanKey key,
+invariant_leq_offset(BtreeCheckState *state, BTScanInsert key,
 					 OffsetNumber upperbound)
 {
-	int16		nkeyatts = IndexRelationGetNumberOfKeyAttributes(state->rel);
 	int32		cmp;
 
-	cmp = _bt_compare(state->rel, nkeyatts, key, state->target, upperbound);
+	cmp = _bt_compare(state->rel, key, state->target, upperbound);
 
 	return cmp <= 0;
 }
@@ -1883,13 +1882,12 @@ invariant_leq_offset(BtreeCheckState *state, ScanKey key,
  * to corruption.
  */
 static inline bool
-invariant_geq_offset(BtreeCheckState *state, ScanKey key,
+invariant_geq_offset(BtreeCheckState *state, BTScanInsert key,
 					 OffsetNumber lowerbound)
 {
-	int16		nkeyatts = IndexRelationGetNumberOfKeyAttributes(state->rel);
 	int32		cmp;
 
-	cmp = _bt_compare(state->rel, nkeyatts, key, state->target, lowerbound);
+	cmp = _bt_compare(state->rel, key, state->target, lowerbound);
 
 	return cmp >= 0;
 }
@@ -1905,14 +1903,12 @@ invariant_geq_offset(BtreeCheckState *state, ScanKey key,
  * to corruption.
  */
 static inline bool
-invariant_leq_nontarget_offset(BtreeCheckState *state,
-							   Page nontarget, ScanKey key,
-							   OffsetNumber upperbound)
+invariant_leq_nontarget_offset(BtreeCheckState *state, BTScanInsert key,
+							   Page nontarget, OffsetNumber upperbound)
 {
-	int16		nkeyatts = IndexRelationGetNumberOfKeyAttributes(state->rel);
 	int32		cmp;
 
-	cmp = _bt_compare(state->rel, nkeyatts, key, nontarget, upperbound);
+	cmp = _bt_compare(state->rel, key, nontarget, upperbound);
 
 	return cmp <= 0;
 }

src/backend/access/nbtree/README

@@ -598,19 +598,22 @@ scankey point to comparison functions that return boolean, such as int4lt.
 There might be more than one scankey entry for a given index column, or
 none at all.  (We require the keys to appear in index column order, but
 the order of multiple keys for a given column is unspecified.)  An
-insertion scankey uses the same array-of-ScanKey data structure, but the
-sk_func pointers point to btree comparison support functions (ie, 3-way
-comparators that return int4 values interpreted as <0, =0, >0).  In an
-insertion scankey there is exactly one entry per index column.  Insertion
-scankeys are built within the btree code (eg, by _bt_mkscankey()) and are
-used to locate the starting point of a scan, as well as for locating the
-place to insert a new index tuple.  (Note: in the case of an insertion
-scankey built from a search scankey, there might be fewer keys than
-index columns, indicating that we have no constraints for the remaining
-index columns.)  After we have located the starting point of a scan, the
-original search scankey is consulted as each index entry is sequentially
-scanned to decide whether to return the entry and whether the scan can
-stop (see _bt_checkkeys()).
+insertion scankey ("BTScanInsert" data structure) uses a similar
+array-of-ScanKey data structure, but the sk_func pointers point to btree
+comparison support functions (ie, 3-way comparators that return int4 values
+interpreted as <0, =0, >0).  In an insertion scankey there is at most one
+entry per index column.  There is also other data about the rules used to
+locate where to begin the scan, such as whether or not the scan is a
+"nextkey" scan.  Insertion scankeys are built within the btree code (eg, by
+_bt_mkscankey()) and are used to locate the starting point of a scan, as
+well as for locating the place to insert a new index tuple.  (Note: in the
+case of an insertion scankey built from a search scankey or built from a
+truncated pivot tuple, there might be fewer keys than index columns,
+indicating that we have no constraints for the remaining index columns.)
+After we have located the starting point of a scan, the original search
+scankey is consulted as each index entry is sequentially scanned to decide
+whether to return the entry and whether the scan can stop (see
+_bt_checkkeys()).
 
 We use term "pivot" index tuples to distinguish tuples which don't point
 to heap tuples, but rather used for tree navigation.  Pivot tuples includes

src/backend/access/nbtree/nbtpage.c

@@ -1371,7 +1371,7 @@ _bt_pagedel(Relation rel, Buffer buf)
 			 */
 			if (!stack)
 			{
-				ScanKey		itup_scankey;
+				BTScanInsert itup_key;
 				ItemId		itemid;
 				IndexTuple	targetkey;
 				Buffer		lbuf;
@@ -1421,12 +1421,10 @@ _bt_pagedel(Relation rel, Buffer buf)
 				}
 
 				/* we need an insertion scan key for the search, so build one */
-				itup_scankey = _bt_mkscankey(rel, targetkey);
-				/* find the leftmost leaf page containing this key */
-				stack = _bt_search(rel,
-								   IndexRelationGetNumberOfKeyAttributes(rel),
-								   itup_scankey, false, &lbuf, BT_READ, NULL);
-				/* don't need a pin on the page */
+				itup_key = _bt_mkscankey(rel, targetkey);
+				/* get stack to leaf page by searching index */
+				stack = _bt_search(rel, itup_key, &lbuf, BT_READ, NULL);
+				/* don't need a lock or second pin on the page */
 				_bt_relbuf(rel, lbuf);
 
 				/*

src/backend/access/nbtree/nbtsort.c

@@ -263,6 +263,7 @@ typedef struct BTWriteState
 {
 	Relation	heap;
 	Relation	index;
+	BTScanInsert inskey;		/* generic insertion scankey */
 	bool		btws_use_wal;	/* dump pages to WAL? */
 	BlockNumber btws_pages_alloced; /* # pages allocated */
 	BlockNumber btws_pages_written; /* # pages written out */
@@ -540,6 +541,7 @@ _bt_leafbuild(BTSpool *btspool, BTSpool *btspool2)
 
 	wstate.heap = btspool->heap;
 	wstate.index = btspool->index;
+	wstate.inskey = _bt_mkscankey(wstate.index, NULL);
 
 	/*
 	 * We need to log index creation in WAL iff WAL archiving/streaming is
@@ -1085,7 +1087,6 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 	TupleDesc	tupdes = RelationGetDescr(wstate->index);
 	int			i,
 				keysz = IndexRelationGetNumberOfKeyAttributes(wstate->index);
-	ScanKey		indexScanKey = NULL;
 	SortSupport sortKeys;
 
 	if (merge)
@@ -1098,7 +1099,6 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 		/* the preparation of merge */
 		itup = tuplesort_getindextuple(btspool->sortstate, true);
 		itup2 = tuplesort_getindextuple(btspool2->sortstate, true);
-		indexScanKey = _bt_mkscankey_nodata(wstate->index);
 
 		/* Prepare SortSupport data for each column */
 		sortKeys = (SortSupport) palloc0(keysz * sizeof(SortSupportData));
@@ -1106,7 +1106,7 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 		for (i = 0; i < keysz; i++)
 		{
 			SortSupport sortKey = sortKeys + i;
-			ScanKey		scanKey = indexScanKey + i;
+			ScanKey		scanKey = wstate->inskey->scankeys + i;
 			int16		strategy;
 
 			sortKey->ssup_cxt = CurrentMemoryContext;
@@ -1125,8 +1125,6 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 			PrepareSortSupportFromIndexRel(wstate->index, strategy, sortKey);
 		}
 
-		_bt_freeskey(indexScanKey);
-
 		for (;;)
 		{
 			load1 = true;		/* load BTSpool next ? */

src/backend/access/nbtree/nbtutils.c

@@ -56,34 +56,37 @@ static bool _bt_check_rowcompare(ScanKey skey,
  *		Build an insertion scan key that contains comparison data from itup
  *		as well as comparator routines appropriate to the key datatypes.
  *
- *		The result is intended for use with _bt_compare().
+ *		Result is intended for use with _bt_compare().  Callers that don't
+ *		need to fill out the insertion scankey arguments (e.g. they use an
+ *		ad-hoc comparison routine) can pass a NULL index tuple.
  */
-ScanKey
+BTScanInsert
 _bt_mkscankey(Relation rel, IndexTuple itup)
 {
+	BTScanInsert key;
 	ScanKey		skey;
 	TupleDesc	itupdesc;
-	int			indnatts PG_USED_FOR_ASSERTS_ONLY;
 	int			indnkeyatts;
 	int16	   *indoption;
+	int			tupnatts;
 	int			i;
 
 	itupdesc = RelationGetDescr(rel);
-	indnatts = IndexRelationGetNumberOfAttributes(rel);
 	indnkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
 	indoption = rel->rd_indoption;
+	tupnatts = itup ? BTreeTupleGetNAtts(itup, rel) : 0;
 
-	Assert(indnkeyatts > 0);
-	Assert(indnkeyatts <= indnatts);
-	Assert(BTreeTupleGetNAtts(itup, rel) == indnatts ||
-		   BTreeTupleGetNAtts(itup, rel) == indnkeyatts);
+	Assert(tupnatts <= IndexRelationGetNumberOfAttributes(rel));
 
 	/*
 	 * We'll execute search using scan key constructed on key columns. Non-key
 	 * (INCLUDE index) columns are always omitted from scan keys.
 	 */
-	skey = (ScanKey) palloc(indnkeyatts * sizeof(ScanKeyData));
-
+	key = palloc(offsetof(BTScanInsertData, scankeys) +
+				 sizeof(ScanKeyData) * indnkeyatts);
+	key->nextkey = false;
+	key->keysz = Min(indnkeyatts, tupnatts);
+	skey = key->scankeys;
 	for (i = 0; i < indnkeyatts; i++)
 	{
 		FmgrInfo   *procinfo;
@@ -96,56 +99,20 @@ _bt_mkscankey(Relation rel, IndexTuple itup)
 		 * comparison can be needed.
 		 */
 		procinfo = index_getprocinfo(rel, i + 1, BTORDER_PROC);
-		arg = index_getattr(itup, i + 1, itupdesc, &null);
-		flags = (null ? SK_ISNULL : 0) | (indoption[i] << SK_BT_INDOPTION_SHIFT);
-		ScanKeyEntryInitializeWithInfo(&skey[i],
-									   flags,
-									   (AttrNumber) (i + 1),
-									   InvalidStrategy,
-									   InvalidOid,
-									   rel->rd_indcollation[i],
-									   procinfo,
-									   arg);
-	}
-
-	return skey;
-}
-
-/*
- * _bt_mkscankey_nodata
- *		Build an insertion scan key that contains 3-way comparator routines
- *		appropriate to the key datatypes, but no comparison data.  The
- *		comparison data ultimately used must match the key datatypes.
- *
- *		The result cannot be used with _bt_compare(), unless comparison
- *		data is first stored into the key entries.  Currently this
- *		routine is only called by nbtsort.c and tuplesort.c, which have
- *		their own comparison routines.
- */
-ScanKey
-_bt_mkscankey_nodata(Relation rel)
-{
-	ScanKey		skey;
-	int			indnkeyatts;
-	int16	   *indoption;
-	int			i;
-
-	indnkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
-	indoption = rel->rd_indoption;
-
-	skey = (ScanKey) palloc(indnkeyatts * sizeof(ScanKeyData));
-
-	for (i = 0; i < indnkeyatts; i++)
-	{
-		FmgrInfo   *procinfo;
-		int			flags;
 
 		/*
-		 * We can use the cached (default) support procs since no cross-type
-		 * comparison can be needed.
+		 * Key arguments built when caller provides no tuple are
+		 * defensively represented as NULL values.  They should never be
+		 * used.
 		 */
-		procinfo = index_getprocinfo(rel, i + 1, BTORDER_PROC);
-		flags = SK_ISNULL | (indoption[i] << SK_BT_INDOPTION_SHIFT);
+		if (i < tupnatts)
+			arg = index_getattr(itup, i + 1, itupdesc, &null);
+		else
+		{
+			arg = (Datum) 0;
+			null = true;
+		}
+		flags = (null ? SK_ISNULL : 0) | (indoption[i] << SK_BT_INDOPTION_SHIFT);
 		ScanKeyEntryInitializeWithInfo(&skey[i],
 									   flags,
 									   (AttrNumber) (i + 1),
@@ -153,19 +120,10 @@ _bt_mkscankey_nodata(Relation rel)
 									   InvalidOid,
 									   rel->rd_indcollation[i],
 									   procinfo,
-									   (Datum) 0);
+									   arg);
 	}
 
-	return skey;
-}
-
-/*
- * free a scan key made by either _bt_mkscankey or _bt_mkscankey_nodata.
- */
-void
-_bt_freeskey(ScanKey skey)
-{
-	pfree(skey);
+	return key;
 }
 
 /*

src/backend/utils/sort/tuplesort.c

@@ -884,7 +884,7 @@ tuplesort_begin_cluster(TupleDesc tupDesc,
 {
 	Tuplesortstate *state = tuplesort_begin_common(workMem, coordinate,
 												   randomAccess);
-	ScanKey		indexScanKey;
+	BTScanInsert indexScanKey;
 	MemoryContext oldcontext;
 	int			i;
 
@@ -919,7 +919,7 @@ tuplesort_begin_cluster(TupleDesc tupDesc,
 
 	state->tupDesc = tupDesc;	/* assume we need not copy tupDesc */
 
-	indexScanKey = _bt_mkscankey_nodata(indexRel);
+	indexScanKey = _bt_mkscankey(indexRel, NULL);
 
 	if (state->indexInfo->ii_Expressions != NULL)
 	{
@@ -945,7 +945,7 @@ tuplesort_begin_cluster(TupleDesc tupDesc,
 	for (i = 0; i < state->nKeys; i++)
 	{
 		SortSupport sortKey = state->sortKeys + i;
-		ScanKey		scanKey = indexScanKey + i;
+		ScanKey		scanKey = indexScanKey->scankeys + i;
 		int16		strategy;
 
 		sortKey->ssup_cxt = CurrentMemoryContext;
@@ -964,7 +964,7 @@ tuplesort_begin_cluster(TupleDesc tupDesc,
 		PrepareSortSupportFromIndexRel(indexRel, strategy, sortKey);
 	}
 
-	_bt_freeskey(indexScanKey);
+	pfree(indexScanKey);
 
 	MemoryContextSwitchTo(oldcontext);
 
@@ -981,7 +981,7 @@ tuplesort_begin_index_btree(Relation heapRel,
 {
 	Tuplesortstate *state = tuplesort_begin_common(workMem, coordinate,
 												   randomAccess);
-	ScanKey		indexScanKey;
+	BTScanInsert indexScanKey;
 	MemoryContext oldcontext;
 	int			i;
 
@@ -1014,7 +1014,7 @@ tuplesort_begin_index_btree(Relation heapRel,
 	state->indexRel = indexRel;
 	state->enforceUnique = enforceUnique;
 
-	indexScanKey = _bt_mkscankey_nodata(indexRel);
+	indexScanKey = _bt_mkscankey(indexRel, NULL);
 
 	/* Prepare SortSupport data for each column */
 	state->sortKeys = (SortSupport) palloc0(state->nKeys *
@@ -1023,7 +1023,7 @@ tuplesort_begin_index_btree(Relation heapRel,
 	for (i = 0; i < state->nKeys; i++)
 	{
 		SortSupport sortKey = state->sortKeys + i;
-		ScanKey		scanKey = indexScanKey + i;
+		ScanKey		scanKey = indexScanKey->scankeys + i;
 		int16		strategy;
 
 		sortKey->ssup_cxt = CurrentMemoryContext;
@@ -1042,7 +1042,7 @@ tuplesort_begin_index_btree(Relation heapRel,
 		PrepareSortSupportFromIndexRel(indexRel, strategy, sortKey);
 	}
 
-	_bt_freeskey(indexScanKey);
+	pfree(indexScanKey);
 
 	MemoryContextSwitchTo(oldcontext);
 

src/include/access/nbtree.h

@@ -319,6 +319,64 @@ typedef struct BTStackData
 
 typedef BTStackData *BTStack;
 
+/*
+ * BTScanInsert is the btree-private state needed to find an initial position
+ * for an indexscan, or to insert new tuples -- an "insertion scankey" (not to
+ * be confused with a search scankey).  It's used to descend a B-Tree using
+ * _bt_search.
+ *
+ * When nextkey is false (the usual case), _bt_search and _bt_binsrch will
+ * locate the first item >= scankey.  When nextkey is true, they will locate
+ * the first item > scan key.
+ *
+ * scankeys is an array of scan key entries for attributes that are compared.
+ * keysz is the size of the array.  During insertion, there must be a scan key
+ * for every attribute, but when starting a regular index scan some can be
+ * omitted.  The array is used as a flexible array member, though it's sized
+ * in a way that makes it possible to use stack allocations.  See
+ * nbtree/README for full details.
+ */
+typedef struct BTScanInsertData
+{
+	bool		nextkey;
+	int			keysz;			/* Size of scankeys array */
+	ScanKeyData scankeys[INDEX_MAX_KEYS];	/* Must appear last */
+} BTScanInsertData;
+
+typedef BTScanInsertData *BTScanInsert;
+
+/*
+ * BTInsertStateData is a working area used during insertion.
+ *
+ * This is filled in after descending the tree to the first leaf page the new
+ * tuple might belong on.  Tracks the current position while performing
+ * uniqueness check, before we have determined which exact page to insert
+ * to.
+ *
+ * (This should be private to nbtinsert.c, but it's also used by
+ * _bt_binsrch_insert)
+ */
+typedef struct BTInsertStateData
+{
+	IndexTuple	itup;			/* Item we're inserting */
+	Size		itemsz;			/* Size of itup -- should be MAXALIGN()'d */
+	BTScanInsert itup_key;		/* Insertion scankey */
+
+	/* Buffer containing leaf page we're likely to insert itup on */
+	Buffer		buf;
+
+	/*
+	 * Cache of bounds within the current buffer.  Only used for insertions
+	 * where _bt_check_unique is called.  See _bt_binsrch_insert and
+	 * _bt_findinsertloc for details.
+	 */
+	bool		bounds_valid;
+	OffsetNumber low;
+	OffsetNumber stricthigh;
+} BTInsertStateData;
+
+typedef BTInsertStateData *BTInsertState;
+
 /*
  * BTScanOpaqueData is the btree-private state needed for an indexscan.
  * This consists of preprocessed scan keys (see _bt_preprocess_keys() for
@@ -558,16 +616,12 @@ extern int	_bt_pagedel(Relation rel, Buffer buf);
 /*
  * prototypes for functions in nbtsearch.c
  */
-extern BTStack _bt_search(Relation rel,
-		   int keysz, ScanKey scankey, bool nextkey,
-		   Buffer *bufP, int access, Snapshot snapshot);
-extern Buffer _bt_moveright(Relation rel, Buffer buf, int keysz,
-			  ScanKey scankey, bool nextkey, bool forupdate, BTStack stack,
-			  int access, Snapshot snapshot);
-extern OffsetNumber _bt_binsrch(Relation rel, Buffer buf, int keysz,
-			ScanKey scankey, bool nextkey);
-extern int32 _bt_compare(Relation rel, int keysz, ScanKey scankey,
-			Page page, OffsetNumber offnum);
+extern BTStack _bt_search(Relation rel, BTScanInsert key, Buffer *bufP,
+		   int access, Snapshot snapshot);
+extern Buffer _bt_moveright(Relation rel, BTScanInsert key, Buffer buf,
+			  bool forupdate, BTStack stack, int access, Snapshot snapshot);
+extern OffsetNumber _bt_binsrch_insert(Relation rel, BTInsertState insertstate);
+extern int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum);
 extern bool _bt_first(IndexScanDesc scan, ScanDirection dir);
 extern bool _bt_next(IndexScanDesc scan, ScanDirection dir);
 extern Buffer _bt_get_endpoint(Relation rel, uint32 level, bool rightmost,
@@ -576,9 +630,7 @@ extern Buffer _bt_get_endpoint(Relation rel, uint32 level, bool rightmost,
 /*
  * prototypes for functions in nbtutils.c
  */
-extern ScanKey _bt_mkscankey(Relation rel, IndexTuple itup);
-extern ScanKey _bt_mkscankey_nodata(Relation rel);
-extern void _bt_freeskey(ScanKey skey);
+extern BTScanInsert _bt_mkscankey(Relation rel, IndexTuple itup);
 extern void _bt_freestack(BTStack stack);
 extern void _bt_preprocess_array_keys(IndexScanDesc scan);
 extern void _bt_start_array_keys(IndexScanDesc scan, ScanDirection dir);