diff --git a/secondary/blockreader.cpp b/secondary/blockreader.cpp
index bae048f6..6a397d10 100644
--- a/secondary/blockreader.cpp
+++ b/secondary/blockreader.cpp
@@ -97,7 +97,7 @@ class SplitBitmap_c
 	FORCE_INLINE int	Scan ( int iStart );
 	FORCE_INLINE int	GetLength() const { return m_iSize; }
 
-	void				Invert() { assert ( 0 && "Unsupported by SplitBitmap_c" ); }
+	void				Invert ( int iMinBit=-1, int iMaxBit=-1 ) { assert ( 0 && "Unsupported by SplitBitmap_c" ); }
 
 	template <typename RESULT>
 	void				Fetch ( int & iIterator, int iBase, RESULT * & pRes, RESULT * pMax );
@@ -203,7 +203,7 @@ class BitmapIterator_i : public BlockIterator_i
 {
 public:
 	virtual void Add ( BlockIterator_i * pIterator ) = 0;
-	virtual void Invert() = 0;
+	virtual void Invert ( RowidRange_t * pBounds ) = 0;
 };
 
 template <typename BITMAP, bool ROWID_RANGE>
@@ -221,7 +221,7 @@ class BitmapIterator_T : public BitmapIterator_i
 	bool		WasCutoffHit() const override		{ return !m_iRowsLeft; }
 
 	void		Add ( BlockIterator_i * pIterator ) override;
-	void		Invert() override					{ m_tBitmap.Invert(); }
+	void		Invert ( RowidRange_t * pBounds ) override	{ m_tBitmap.Invert ( pBounds ? pBounds->m_uMin : -1, pBounds ? pBounds->m_uMax : -1 ); }
 
 private:
 	static const int			RESULT_BLOCK_SIZE = 1024;
@@ -407,7 +407,7 @@ class ReaderTraits_c : public BlockReader_i
 	int							m_iCutoff = 0;
 
 	bool				NeedBitmapIterator() const;
-	BitmapIterator_i *	SpawnBitmapIterator ( const RowidRange_t * pBounds = nullptr, const Filter_t * pRange = nullptr ) const;
+	BitmapIterator_i *	SpawnBitmapIterator ( const RowidRange_t * pBounds, bool bExclude ) const;
 	void				LoadValueBlockData ( bool bOnlyCount, FileReader_c & tReader );
 	uint32_t			CalcNumBlockValues ( int iBlock ) const;
 };
@@ -440,10 +440,11 @@ bool ReaderTraits_c::NeedBitmapIterator() const
 }
 
 
-BitmapIterator_i * ReaderTraits_c::SpawnBitmapIterator ( const RowidRange_t * pBounds, const Filter_t * pRange ) const
+BitmapIterator_i * ReaderTraits_c::SpawnBitmapIterator ( const RowidRange_t * pBounds, bool bExclude ) const
 {
-	// force bitmap iterator for IS NULL queries
-	if ( pRange && pRange->m_eType==common::FilterType_e::NOTNULL && pRange->m_bExclude )
+	// force bitmap iterator for exclude filters
+	// FIXME! make invertable split bitmaps
+	if ( bExclude )
 	{
 		if ( pBounds )
 			return new BitmapIterator_T<BitVec_T<uint64_t>, true> ( m_sAttr, m_tRsetInfo.m_uRowsCount, pBounds );
@@ -517,8 +518,8 @@ class BlockReader_c : public ReaderTraits_c
 public:
 				BlockReader_c ( const ReaderFactory_c & tCtx, std::shared_ptr<IntCodec_i> & pCodec );
 
-	void		CreateBlocksIterator ( const std::vector<BlockIter_t> & dIt, std::vector<BlockIterator_i *> & dRes ) override;
-	void		CreateBlocksIterator ( const BlockIter_t & tIt, const Filter_t & tVal, std::vector<BlockIterator_i *> & dRes ) override { assert ( 0 && "Requesting range iterators from block reader" ); }
+	void		CreateBlocksIterator ( const std::vector<BlockIter_t> & dIt, const Filter_t & tFilter, std::vector<BlockIterator_i *> & dRes ) override;
+	void		CreateBlocksIterator ( const BlockIter_t & tIt, const Filter_t & tFilter, std::vector<BlockIterator_i *> & dRes ) override { assert ( 0 && "Requesting range iterators from block reader" ); }
 	uint32_t	CalcValueCount ( const std::vector<BlockIter_t> & dIt ) override;
 	uint32_t	CalcValueCount ( const BlockIter_t & tIt, const common::Filter_t & tVal ) override { assert ( 0 && "Requesting range iterators from block reader" ); return 0; }
 
@@ -639,17 +640,21 @@ void BlockReader_c::CreateBlocksIterator ( const BlockIter_t & tIt, ADDITERATOR
 }
 
 
-void BlockReader_c::CreateBlocksIterator ( const std::vector<BlockIter_t> & dIt, std::vector<BlockIterator_i *> & dRes )
+void BlockReader_c::CreateBlocksIterator ( const std::vector<BlockIter_t> & dIt, const Filter_t & tFilter, std::vector<BlockIterator_i *> & dRes )
 {
 	// add bitmap iterator as 1st element of dRes on exit
 	std::function<void( BitmapIterator_i * pIterator )> fnDeleter = [&]( BitmapIterator_i * pIterator ){ if ( pIterator ) { assert(dRes.empty()); dRes.push_back(pIterator); } };
-	std::unique_ptr<BitmapIterator_i, decltype(fnDeleter)> pBitmapIterator ( SpawnBitmapIterator(), fnDeleter );
+	RowidRange_t * pBounds = m_bHaveBounds ? &m_tBounds : nullptr;
+	std::unique_ptr<BitmapIterator_i, decltype(fnDeleter)> pBitmapIterator ( SpawnBitmapIterator ( pBounds, tFilter.m_bExclude ), fnDeleter );
 	if ( pBitmapIterator && m_iCutoff>=0 )
 		pBitmapIterator->SetCutoff(m_iCutoff);
 
 	std::unique_ptr<BlockIteratorWithSetup_i> pCommonIterator;
 	for ( auto & i : dIt )
 		CreateBlocksIterator ( i, [this, &dRes, &pBitmapIterator, &pCommonIterator]( int iItem ){ AddIterator ( iItem, dRes, pBitmapIterator.get(), pCommonIterator ); } );
+
+	if ( tFilter.m_bExclude )
+		pBitmapIterator->Invert(pBounds);
 }
 
 
@@ -829,8 +834,8 @@ class RangeReader_c : public ReaderTraits_c
 public:
 				RangeReader_c ( const ReaderFactory_c & tCtx, std::shared_ptr<IntCodec_i> & pCodec );
 
-	void		CreateBlocksIterator ( const std::vector<BlockIter_t> & dIt, std::vector<BlockIterator_i *> & dRes ) override { assert ( 0 && "Requesting block iterators from range reader" ); }
-	void		CreateBlocksIterator ( const BlockIter_t & tIt, const Filter_t & tRange, std::vector<BlockIterator_i *> & dRes ) override;
+	void		CreateBlocksIterator ( const std::vector<BlockIter_t> & dIt, const Filter_t & tFilter, std::vector<BlockIterator_i *> & dRes ) override { assert ( 0 && "Requesting block iterators from range reader" ); }
+	void		CreateBlocksIterator ( const BlockIter_t & tIt, const Filter_t & tFilter, std::vector<BlockIterator_i *> & dRes ) override;
 	uint32_t	CalcValueCount ( const std::vector<BlockIter_t> & dIt ) override { assert ( 0 && "Requesting block iterators from range reader" ); return 0; }
 	uint32_t	CalcValueCount ( const BlockIter_t & tIt, const common::Filter_t & tRange ) override;
 
@@ -1017,22 +1022,20 @@ void RangeReader_c::CreateBlocksIterator ( const BlockIter_t & tIt, const Filter
 }
 
 
-void RangeReader_c::CreateBlocksIterator ( const BlockIter_t & tIt, const Filter_t & tRange, std::vector<BlockIterator_i *> & dRes )
+void RangeReader_c::CreateBlocksIterator ( const BlockIter_t & tIt, const Filter_t & tFilter, std::vector<BlockIterator_i *> & dRes )
 {
 	// add bitmap iterator as 1st element of dRes on exit
 	std::function<void( BitmapIterator_i * pIterator )> fnDeleter = [&]( BitmapIterator_i * pIterator ){ if ( pIterator ) { assert(dRes.empty()); dRes.push_back(pIterator); } };
-	std::unique_ptr<BitmapIterator_i, decltype(fnDeleter)> pBitmapIterator ( SpawnBitmapIterator ( m_bHaveBounds ? &m_tBounds : nullptr, &tRange ), fnDeleter );
+	RowidRange_t * pBounds = m_bHaveBounds ? &m_tBounds : nullptr;
+	std::unique_ptr<BitmapIterator_i, decltype(fnDeleter)> pBitmapIterator ( SpawnBitmapIterator ( pBounds, tFilter.m_bExclude ), fnDeleter );
 	if ( pBitmapIterator && m_iCutoff>=0 )
 		pBitmapIterator->SetCutoff(m_iCutoff);
 
 	std::unique_ptr<BlockIteratorWithSetup_i> pCommonIterator;
-	CreateBlocksIterator ( tIt, tRange, [this, &dRes, &pBitmapIterator, &pCommonIterator]( int iValCur, bool bLoad ){ return AddIterator ( iValCur, bLoad, dRes, pBitmapIterator.get(), pCommonIterator ); } );
+	CreateBlocksIterator ( tIt, tFilter, [this, &dRes, &pBitmapIterator, &pCommonIterator]( int iValCur, bool bLoad ){ return AddIterator ( iValCur, bLoad, dRes, pBitmapIterator.get(), pCommonIterator ); } );
 
-	if ( tRange.m_eType==common::FilterType_e::NOTNULL && tRange.m_bExclude )
-	{
-		assert(pBitmapIterator);
-		pBitmapIterator->Invert();
-	}
+	if ( tFilter.m_bExclude )
+		pBitmapIterator->Invert(pBounds);
 }
 
 
diff --git a/secondary/blockreader.h b/secondary/blockreader.h
index c3a43212..45fa9532 100644
--- a/secondary/blockreader.h
+++ b/secondary/blockreader.h
@@ -52,8 +52,8 @@ class BlockReader_i
 public:
 	virtual				~BlockReader_i() = default;
 
-	virtual void		CreateBlocksIterator ( const std::vector<BlockIter_t> & dIt, std::vector<common::BlockIterator_i *> & dRes ) = 0;
-	virtual void		CreateBlocksIterator ( const BlockIter_t & tIt, const common::Filter_t & tVal, std::vector<common::BlockIterator_i *> & dRes ) = 0;
+	virtual void		CreateBlocksIterator ( const std::vector<BlockIter_t> & dIt, const common::Filter_t & tFilter, std::vector<common::BlockIterator_i *> & dRes ) = 0;
+	virtual void		CreateBlocksIterator ( const BlockIter_t & tIt, const common::Filter_t & tFilter, std::vector<common::BlockIterator_i *> & dRes ) = 0;
 	virtual uint32_t	CalcValueCount ( const std::vector<BlockIter_t> & dIt ) = 0;
 	virtual uint32_t	CalcValueCount ( const BlockIter_t & tIt, const common::Filter_t & tVal ) = 0;
 };
diff --git a/secondary/secondary.cpp b/secondary/secondary.cpp
index 2164a878..c2956a26 100644
--- a/secondary/secondary.cpp
+++ b/secondary/secondary.cpp
@@ -338,7 +338,7 @@ int64_t SecondaryIndex_c::GetValsRows ( std::vector<BlockIterator_i *> * pIterat
 	if ( !pBlockReader )
 		return 0;
 
-	pBlockReader->CreateBlocksIterator ( dBlocksIt, *pIterators );
+	pBlockReader->CreateBlocksIterator ( dBlocksIt, tFilter, *pIterators );
 	return iNumIterators;
 }
 
diff --git a/util/bitvec.h b/util/bitvec.h
index f07ee451..c92f9114 100644
--- a/util/bitvec.h
+++ b/util/bitvec.h
@@ -47,15 +47,29 @@ class BitVec_T
 		m_dData [ iBit>>SHIFT ] |= ( (T)1 )<<( iBit&MASK );
 	}
 
-	void Invert()
+	void Invert ( int iMinBit=-1, int iMaxBit=-1 )
 	{
-		for ( auto & i : m_dData )
-			i = ~i;
+		if ( iMinBit<0 )
+			iMinBit = 0;
 
-		if ( m_iSize!=m_iDataLen << SHIFT )
+		if ( iMaxBit<0 )
+			iMaxBit = m_iSize;
+
+		int iMinId = iMinBit>>SHIFT;
+		int iMaxId = (iMaxBit+SIZEBITS-1)>>SHIFT;
+		for ( int i = iMinId; i<iMaxId; i++ )
+			m_dData[i] = ~m_dData[i];
+
+		if ( ( iMinId<<SHIFT ) != iMinBit )
+		{
+			int iFirstBit = iMinId << SHIFT;
+			m_dData[iMinId] &= ~((T(1) << ( iMinBit-iFirstBit )) - 1);
+		}
+
+		if ( ( iMaxId<<SHIFT ) != iMaxBit )
 		{
-			int iFirstBit = (m_iDataLen-1) << SHIFT;
-			m_dData.back() &= (T(1) << ( m_iSize-iFirstBit )) - 1;
+			int iFirstBit = (iMaxId-1) << SHIFT;
+			m_dData[iMaxId-1] &= (T(1) << ( iMaxBit-iFirstBit )) - 1;
 		}
 	}