YQL-15949: Support skip of complex types

YQL-15949: Support skip of complex types

13 files changed, 426 insertions, 102 deletions

diff --git a/ydb/library/yql/parser/pg_wrapper/comp_factory.cpp b/ydb/library/yql/parser/pg_wrapper/comp_factory.cpp
index f4a2f3fc28a..254a7a1e35b 100644
--- a/ydb/library/yql/parser/pg_wrapper/comp_factory.cpp
+++ b/ydb/library/yql/parser/pg_wrapper/comp_factory.cpp
@@ -2285,6 +2285,38 @@ NUdf::TUnboxedValue ReadYsonValuePg(TPgType* type, char cmd, TInputBuf& buf) {
     return PgValueFromString(s, type->GetTypeId());
 }
 
+void SkipSkiffPg(TPgType* type, NCommon::TInputBuf& buf) {
+    auto marker = buf.Read();
+    if (!marker) {
+        return;
+    }
+
+    switch (type->GetTypeId()) {
+    case BOOLOID: {
+        buf.Read();
+        return;
+    }
+    case INT2OID:
+    case INT4OID:
+    case INT8OID: {
+        buf.SkipMany(sizeof(i64));
+        return;
+    }
+    case FLOAT4OID:
+    case FLOAT8OID: {
+        buf.SkipMany(sizeof(double));
+        return;
+    }
+    default: {
+        ui32 size;
+        buf.ReadMany((char*)&size, sizeof(size));
+        CHECK_STRING_LENGTH_UNSIGNED(size);
+        buf.SkipMany(size);
+        return;
+    }
+    }
+}
+
 NUdf::TUnboxedValue ReadSkiffPg(TPgType* type, NCommon::TInputBuf& buf) {
     auto marker = buf.Read();
     if (!marker) {
diff --git a/ydb/library/yql/parser/pg_wrapper/interface/codec.h b/ydb/library/yql/parser/pg_wrapper/interface/codec.h
index 979f4915041..f672a8cad1d 100644
--- a/ydb/library/yql/parser/pg_wrapper/interface/codec.h
+++ b/ydb/library/yql/parser/pg_wrapper/interface/codec.h
@@ -39,6 +39,8 @@ void WriteYsonValueInTableFormatPg(TOutputBuf& buf, NKikimr::NMiniKQL::TPgType*
 NUdf::TUnboxedValue ReadYsonValueInTableFormatPg(NKikimr::NMiniKQL::TPgType* type, char cmd, TInputBuf& buf);
 NUdf::TUnboxedValue ReadYsonValuePg(NKikimr::NMiniKQL::TPgType* type, char cmd, TInputBuf& buf);
 
+void SkipSkiffPg(NKikimr::NMiniKQL::TPgType* type, TInputBuf& buf);
+
 NKikimr::NUdf::TUnboxedValue ReadSkiffPg(NKikimr::NMiniKQL::TPgType* type, TInputBuf& buf);
 void WriteSkiffPg(NKikimr::NMiniKQL::TPgType* type, const NKikimr::NUdf::TUnboxedValuePod& value, TOutputBuf& buf);
 
diff --git a/ydb/library/yql/providers/common/codec/yql_codec.cpp b/ydb/library/yql/providers/common/codec/yql_codec.cpp
index 2d135d002f5..a404e27f9f0 100644
--- a/ydb/library/yql/providers/common/codec/yql_codec.cpp
+++ b/ydb/library/yql/providers/common/codec/yql_codec.cpp
@@ -753,10 +753,14 @@ NUdf::TUnboxedValue ReadYsonValue(TType* type,
 
         CHECK_EXPECTED(cmd, BeginListSymbol);
         cmd = buf.Read();
-        ui64 index = 0;
+        i64 index = 0;
         if (isTableFormat) {
-            CHECK_EXPECTED(cmd, Uint64Marker);
-            index = buf.ReadVarUI64();
+            YQL_ENSURE(cmd == Int64Marker || cmd == Uint64Marker);
+            if (cmd == Uint64Marker) {
+                index = buf.ReadVarUI64();
+            } else {
+                index = buf.ReadVarI64();
+            }
         } else {
             if (cmd == BeginListSymbol) {
                 cmd = buf.Read();
@@ -1021,8 +1025,7 @@ NUdf::TUnboxedValue ReadYsonValue(TType* type,
 
             CHECK_EXPECTED(cmd, EndListSymbol);
             return ret;
-        }
-        else {
+        } else {
             cmd = buf.Read();
 
             for (;;) {
@@ -1524,6 +1527,176 @@ NUdf::TUnboxedValue ReadSkiffData(TType* type, ui64 nativeYtTypeFlags, TInputBuf
     }
 }
 
+void SkipSkiffField(NKikimr::NMiniKQL::TType* type, ui64 nativeYtTypeFlags, TInputBuf& buf) {
+    const bool isOptional = type->IsOptional();
+    if (isOptional) {
+        // Unwrap optional
+        type = static_cast<TOptionalType*>(type)->GetItemType();
+    }
+
+    if (isOptional) {
+        auto marker = buf.Read();
+        if (!marker) {
+            return;
+        }
+    }
+
+    if (type->IsData()) {
+        auto schemeType = static_cast<TDataType*>(type)->GetSchemeType();
+        switch (schemeType) {
+        case NUdf::TDataType<bool>::Id:
+            buf.SkipMany(sizeof(ui8));
+            break;
+
+        case NUdf::TDataType<ui8>::Id:
+        case NUdf::TDataType<ui16>::Id:
+        case NUdf::TDataType<ui32>::Id:
+        case NUdf::TDataType<ui64>::Id:
+        case NUdf::TDataType<NUdf::TDate>::Id:
+        case NUdf::TDataType<NUdf::TDatetime>::Id:
+        case NUdf::TDataType<NUdf::TTimestamp>::Id:
+            buf.SkipMany(sizeof(ui64));
+            break;
+
+        case NUdf::TDataType<i8>::Id:
+        case NUdf::TDataType<i16>::Id:
+        case NUdf::TDataType<i32>::Id:
+        case NUdf::TDataType<i64>::Id:
+        case NUdf::TDataType<NUdf::TInterval>::Id:
+            buf.SkipMany(sizeof(i64));
+            break;
+
+        case NUdf::TDataType<float>::Id:
+        case NUdf::TDataType<double>::Id:
+            buf.SkipMany(sizeof(double));
+            break;
+
+        case NUdf::TDataType<NUdf::TUtf8>::Id:
+        case NUdf::TDataType<char*>::Id:
+        case NUdf::TDataType<NUdf::TJson>::Id:
+        case NUdf::TDataType<NUdf::TYson>::Id:
+        case NUdf::TDataType<NUdf::TUuid>::Id:
+        case NUdf::TDataType<NUdf::TDyNumber>::Id:
+        case NUdf::TDataType<NUdf::TTzDate>::Id:
+        case NUdf::TDataType<NUdf::TTzDatetime>::Id:
+        case NUdf::TDataType<NUdf::TTzTimestamp>::Id:
+        case NUdf::TDataType<NUdf::TJsonDocument>::Id: {
+            ui32 size;
+            buf.ReadMany((char*)&size, sizeof(size));
+            CHECK_STRING_LENGTH_UNSIGNED(size);
+            buf.SkipMany(size);
+            break;
+        }
+        case NUdf::TDataType<NUdf::TDecimal>::Id: {
+            if (nativeYtTypeFlags & NTCF_DECIMAL) {
+                auto const params = static_cast<TDataDecimalType*>(type)->GetParams();
+                if (params.first < 10) {
+                    buf.SkipMany(sizeof(i32));
+                } else if (params.first < 19) {
+                    buf.SkipMany(sizeof(i64));
+                } else {
+                    buf.SkipMany(sizeof(NDecimal::TInt128));
+                }
+            } else {
+                ui32 size;
+                buf.ReadMany((char*)&size, sizeof(size));
+                CHECK_STRING_LENGTH_UNSIGNED(size);
+                buf.SkipMany(size);
+            }
+            break;
+        }
+        default:
+            YQL_ENSURE(false, "Unsupported data type: " << schemeType);
+        }
+        return;
+    }
+
+    if (type->IsPg()) {
+        SkipSkiffPg(static_cast<TPgType*>(type), buf);
+        return;
+    }
+
+    if (type->IsStruct()) {
+        auto structType = static_cast<TStructType*>(type);
+        const std::vector<size_t>* reorder = nullptr;
+        if (auto cookie = structType->GetCookie()) {
+            reorder = ((const std::vector<size_t>*)cookie);
+        }
+        for (ui32 i = 0; i < structType->GetMembersCount(); ++i) {
+            SkipSkiffField(structType->GetMemberType(reorder ? reorder->at(i) : i), nativeYtTypeFlags, buf);
+        }
+        return;
+    }
+
+    if (type->IsList()) {
+        auto itemType = static_cast<TListType*>(type)->GetItemType();
+        while (buf.Read() == '\0') {
+            SkipSkiffField(itemType, nativeYtTypeFlags, buf);
+        }
+        return;
+    }
+
+    if (type->IsTuple()) {
+        auto tupleType = static_cast<TTupleType*>(type);
+
+        for (ui32 i = 0; i < tupleType->GetElementsCount(); ++i) {
+            SkipSkiffField(tupleType->GetElementType(i), nativeYtTypeFlags, buf);
+        }
+        return;
+    }
+
+    if (type->IsVariant()) {
+        auto varType = AS_TYPE(TVariantType, type);
+        ui16 data = 0;
+        if (varType->GetAlternativesCount() < 256) {
+            buf.ReadMany((char*)&data, 1);
+        } else {
+            buf.ReadMany((char*)&data, sizeof(data));
+        }
+        
+        if (varType->GetUnderlyingType()->IsTuple()) {
+            auto tupleType = AS_TYPE(TTupleType, varType->GetUnderlyingType());
+            YQL_ENSURE(data < tupleType->GetElementsCount());
+            SkipSkiffField(tupleType->GetElementType(data), nativeYtTypeFlags, buf);
+        } else {
+            auto structType = AS_TYPE(TStructType, varType->GetUnderlyingType());
+            if (auto cookie = structType->GetCookie()) {
+                const std::vector<size_t>& reorder = *((const std::vector<size_t>*)cookie);
+                data = reorder[data];
+            }
+            YQL_ENSURE(data < structType->GetMembersCount());
+
+            SkipSkiffField(structType->GetMemberType(data), nativeYtTypeFlags, buf);
+        }
+        return;
+    }
+
+    if (type->IsVoid()) {
+        return;
+    }
+
+    if (type->IsNull()) {
+        return;
+    }
+
+    if (type->IsEmptyList() || type->IsEmptyDict()) {
+        return;
+    }
+
+    if (type->IsDict()) {
+        auto dictType = AS_TYPE(TDictType, type);
+        auto keyType = dictType->GetKeyType();
+        auto payloadType = dictType->GetPayloadType();
+        while (buf.Read() == '\0') {
+            SkipSkiffField(keyType, nativeYtTypeFlags, buf);
+            SkipSkiffField(payloadType, nativeYtTypeFlags, buf);
+        }
+        return;
+    }
+
+    YQL_ENSURE(false, "Unsupported type for skip: " << type->GetKindAsStr());
+}
+
 NKikimr::NUdf::TUnboxedValue ReadSkiffNativeYtValue(NKikimr::NMiniKQL::TType* type, ui64 nativeYtTypeFlags,
     const NKikimr::NMiniKQL::THolderFactory& holderFactory, TInputBuf& buf)
 {
diff --git a/ydb/library/yql/providers/common/codec/yql_codec.h b/ydb/library/yql/providers/common/codec/yql_codec.h
index 39a95196c3c..351c2e3322b 100644
--- a/ydb/library/yql/providers/common/codec/yql_codec.h
+++ b/ydb/library/yql/providers/common/codec/yql_codec.h
@@ -77,6 +77,8 @@ extern "C" void ReadYsonContainerValue(NKikimr::NMiniKQL::TType* type,
     const NKikimr::NMiniKQL::THolderFactory& holderFactory, NKikimr::NUdf::TUnboxedValue& value, NCommon::TInputBuf& buf,
     bool wrapOptional);
 
+void SkipSkiffField(NKikimr::NMiniKQL::TType* type, ui64 nativeYtTypeFlags, TInputBuf& buf);
+
 NKikimr::NUdf::TUnboxedValue ReadSkiffNativeYtValue(NKikimr::NMiniKQL::TType* type, ui64 nativeYtTypeFlags,
     const NKikimr::NMiniKQL::THolderFactory& holderFactory, TInputBuf& buf);
 
diff --git a/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.darwin-x86_64.txt b/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.darwin-x86_64.txt
index 0105a602cfa..a96cbb28b36 100644
--- a/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.darwin-x86_64.txt
+++ b/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.darwin-x86_64.txt
@@ -76,7 +76,7 @@ add_custom_command(
   -globalopt
   -globaldce
   -internalize
-  -internalize-public-api-list=WriteJust#WriteNothing#WriteBool#Write8#Write16#Write32#Write64#Write120#WriteDecimal32#WriteDecimal64#WriteDecimal128#WriteFloat#WriteDouble#WriteString#ReadBool#ReadInt8#ReadUint8#ReadInt16#ReadUint16#ReadInt32#ReadUint32#ReadInt64#ReadUint64#ReadInt120#ReadDecimal32#ReadDecimal64#ReadDecimal128#ReadFloat#ReadDouble#ReadOptional#SkipFixedData#SkipVarData#ReadTzDate#ReadTzDatetime#ReadTzTimestamp#WriteTzDate#WriteTzDatetime#WriteTzTimestamp#GetWrittenBytes#FillZero
+  -internalize-public-api-list=WriteJust#WriteNothing#WriteBool#Write8#Write16#Write32#Write64#Write120#WriteDecimal32#WriteDecimal64#WriteDecimal128#WriteFloat#WriteDouble#WriteString#ReadBool#ReadInt8#ReadUint8#ReadInt16#ReadUint16#ReadInt32#ReadUint32#ReadInt64#ReadUint64#ReadInt120#ReadDecimal32#ReadDecimal64#ReadDecimal128#ReadFloat#ReadDouble#ReadOptional#ReadVariantData#SkipFixedData#SkipVarData#ReadTzDate#ReadTzDatetime#ReadTzTimestamp#WriteTzDate#WriteTzDatetime#WriteTzTimestamp#GetWrittenBytes#FillZero
 )
 add_custom_command(
   OUTPUT
diff --git a/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.linux-aarch64.txt b/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.linux-aarch64.txt
index fba2ebc670b..171d66fff4b 100644
--- a/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.linux-aarch64.txt
+++ b/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.linux-aarch64.txt
@@ -78,7 +78,7 @@ add_custom_command(
   -globalopt
   -globaldce
   -internalize
-  -internalize-public-api-list=WriteJust#WriteNothing#WriteBool#Write8#Write16#Write32#Write64#Write120#WriteDecimal32#WriteDecimal64#WriteDecimal128#WriteFloat#WriteDouble#WriteString#ReadBool#ReadInt8#ReadUint8#ReadInt16#ReadUint16#ReadInt32#ReadUint32#ReadInt64#ReadUint64#ReadInt120#ReadDecimal32#ReadDecimal64#ReadDecimal128#ReadFloat#ReadDouble#ReadOptional#SkipFixedData#SkipVarData#ReadTzDate#ReadTzDatetime#ReadTzTimestamp#WriteTzDate#WriteTzDatetime#WriteTzTimestamp#GetWrittenBytes#FillZero
+  -internalize-public-api-list=WriteJust#WriteNothing#WriteBool#Write8#Write16#Write32#Write64#Write120#WriteDecimal32#WriteDecimal64#WriteDecimal128#WriteFloat#WriteDouble#WriteString#ReadBool#ReadInt8#ReadUint8#ReadInt16#ReadUint16#ReadInt32#ReadUint32#ReadInt64#ReadUint64#ReadInt120#ReadDecimal32#ReadDecimal64#ReadDecimal128#ReadFloat#ReadDouble#ReadOptional#ReadVariantData#SkipFixedData#SkipVarData#ReadTzDate#ReadTzDatetime#ReadTzTimestamp#WriteTzDate#WriteTzDatetime#WriteTzTimestamp#GetWrittenBytes#FillZero
 )
 add_custom_command(
   OUTPUT
diff --git a/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.linux-x86_64.txt b/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.linux-x86_64.txt
index fba2ebc670b..171d66fff4b 100644
--- a/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.linux-x86_64.txt
+++ b/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.linux-x86_64.txt
@@ -78,7 +78,7 @@ add_custom_command(
   -globalopt
   -globaldce
   -internalize
-  -internalize-public-api-list=WriteJust#WriteNothing#WriteBool#Write8#Write16#Write32#Write64#Write120#WriteDecimal32#WriteDecimal64#WriteDecimal128#WriteFloat#WriteDouble#WriteString#ReadBool#ReadInt8#ReadUint8#ReadInt16#ReadUint16#ReadInt32#ReadUint32#ReadInt64#ReadUint64#ReadInt120#ReadDecimal32#ReadDecimal64#ReadDecimal128#ReadFloat#ReadDouble#ReadOptional#SkipFixedData#SkipVarData#ReadTzDate#ReadTzDatetime#ReadTzTimestamp#WriteTzDate#WriteTzDatetime#WriteTzTimestamp#GetWrittenBytes#FillZero
+  -internalize-public-api-list=WriteJust#WriteNothing#WriteBool#Write8#Write16#Write32#Write64#Write120#WriteDecimal32#WriteDecimal64#WriteDecimal128#WriteFloat#WriteDouble#WriteString#ReadBool#ReadInt8#ReadUint8#ReadInt16#ReadUint16#ReadInt32#ReadUint32#ReadInt64#ReadUint64#ReadInt120#ReadDecimal32#ReadDecimal64#ReadDecimal128#ReadFloat#ReadDouble#ReadOptional#ReadVariantData#SkipFixedData#SkipVarData#ReadTzDate#ReadTzDatetime#ReadTzTimestamp#WriteTzDate#WriteTzDatetime#WriteTzTimestamp#GetWrittenBytes#FillZero
 )
 add_custom_command(
   OUTPUT
diff --git a/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.windows-x86_64.txt b/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.windows-x86_64.txt
index 0105a602cfa..a96cbb28b36 100644
--- a/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.windows-x86_64.txt
+++ b/ydb/library/yql/providers/yt/codec/codegen/CMakeLists.windows-x86_64.txt
@@ -76,7 +76,7 @@ add_custom_command(
   -globalopt
   -globaldce
   -internalize
-  -internalize-public-api-list=WriteJust#WriteNothing#WriteBool#Write8#Write16#Write32#Write64#Write120#WriteDecimal32#WriteDecimal64#WriteDecimal128#WriteFloat#WriteDouble#WriteString#ReadBool#ReadInt8#ReadUint8#ReadInt16#ReadUint16#ReadInt32#ReadUint32#ReadInt64#ReadUint64#ReadInt120#ReadDecimal32#ReadDecimal64#ReadDecimal128#ReadFloat#ReadDouble#ReadOptional#SkipFixedData#SkipVarData#ReadTzDate#ReadTzDatetime#ReadTzTimestamp#WriteTzDate#WriteTzDatetime#WriteTzTimestamp#GetWrittenBytes#FillZero
+  -internalize-public-api-list=WriteJust#WriteNothing#WriteBool#Write8#Write16#Write32#Write64#Write120#WriteDecimal32#WriteDecimal64#WriteDecimal128#WriteFloat#WriteDouble#WriteString#ReadBool#ReadInt8#ReadUint8#ReadInt16#ReadUint16#ReadInt32#ReadUint32#ReadInt64#ReadUint64#ReadInt120#ReadDecimal32#ReadDecimal64#ReadDecimal128#ReadFloat#ReadDouble#ReadOptional#ReadVariantData#SkipFixedData#SkipVarData#ReadTzDate#ReadTzDatetime#ReadTzTimestamp#WriteTzDate#WriteTzDatetime#WriteTzTimestamp#GetWrittenBytes#FillZero
 )
 add_custom_command(
   OUTPUT
diff --git a/ydb/library/yql/providers/yt/codec/codegen/ya.make b/ydb/library/yql/providers/yt/codec/codegen/ya.make
index 79b07b27260..422511b8dae 100644
--- a/ydb/library/yql/providers/yt/codec/codegen/ya.make
+++ b/ydb/library/yql/providers/yt/codec/codegen/ya.make
@@ -59,6 +59,7 @@ IF (NOT MKQL_DISABLE_CODEGEN)
         ReadFloat
         ReadDouble
         ReadOptional
+        ReadVariantData
         SkipFixedData
         SkipVarData
         ReadTzDate
diff --git a/ydb/library/yql/providers/yt/codec/codegen/yt_codec_bc.cpp b/ydb/library/yql/providers/yt/codec/codegen/yt_codec_bc.cpp
index c0deefdcd4d..fd7efec8e1c 100644
--- a/ydb/library/yql/providers/yt/codec/codegen/yt_codec_bc.cpp
+++ b/ydb/library/yql/providers/yt/codec/codegen/yt_codec_bc.cpp
@@ -205,6 +205,17 @@ extern "C" ui8 ReadOptional(void* vbuf) {
     return buf.Read();
 }
 
+extern "C" ui16 ReadVariantData(void* vbuf, ui8 oneByte) {
+    NCommon::TInputBuf& buf = *(NCommon::TInputBuf*)vbuf;
+    if (oneByte) {
+        return buf.Read();
+    } else {
+        ui16 data = 0;
+        buf.ReadMany((char*)&data, sizeof(data));
+        return data;
+    }
+}
+
 extern "C" void SkipFixedData(void* vbuf, ui64 size) {
     NCommon::TInputBuf& buf = *(NCommon::TInputBuf*)vbuf;
     buf.SkipMany(size);
diff --git a/ydb/library/yql/providers/yt/codec/codegen/yt_codec_cg.cpp b/ydb/library/yql/providers/yt/codec/codegen/yt_codec_cg.cpp
index 7547f3580d9..382c1ef6f2d 100644
--- a/ydb/library/yql/providers/yt/codec/codegen/yt_codec_cg.cpp
+++ b/ydb/library/yql/providers/yt/codec/codegen/yt_codec_cg.cpp
@@ -832,9 +832,154 @@ private:
             default:
                 YQL_ENSURE(false, "Unknown data type: " << schemeType);
             }
-        } else {
-            ythrow yexception() << "Skip of complex types is not supported";
+            return;
+        }
+
+        if (type->IsStruct()) {
+            auto structType = static_cast<TStructType*>(type);
+            const std::vector<size_t>* reorder = nullptr;
+            if (auto cookie = structType->GetCookie()) {
+                reorder = ((const std::vector<size_t>*)cookie);
+            }
+            for (ui32 i = 0; i < structType->GetMembersCount(); ++i) {
+                GenerateSkip(buf, structType->GetMemberType(reorder ? reorder->at(i) : i), nativeYtTypeFlags);
+            }
+            return;
+        }
+
+        if (type->IsTuple()) {
+            auto tupleType = static_cast<TTupleType*>(type);
+            for (ui32 i = 0; i < tupleType->GetElementsCount(); ++i) {
+                GenerateSkip(buf, tupleType->GetElementType(i), nativeYtTypeFlags);
+            }
+            return;
+        }
+
+        if (type->IsList()) {
+            auto itemType = static_cast<TListType*>(type)->GetItemType();
+            const auto done = BasicBlock::Create(context, "done", Func_);
+            const auto listEndMarker = ConstantInt::get(Type::getInt8Ty(context), 0xFF);
+            const auto innerSkip = BasicBlock::Create(context, "innerSkip", Func_);
+            const auto listContinue = BasicBlock::Create(context, "listContinue", Func_);
+            BranchInst::Create(listContinue, Block_);
+
+            {
+                Block_ = innerSkip;
+                GenerateSkip(buf, itemType, nativeYtTypeFlags);
+                BranchInst::Create(listContinue, Block_);
+            }
+            {
+                Block_ = listContinue;
+                const auto marker = CallInst::Create(module.getFunction("ReadOptional"), { buf }, "optMarker", Block_);
+                const auto check = CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_EQ, marker, listEndMarker, "exists", Block_);
+                BranchInst::Create(done, innerSkip, check, Block_);
+            }
+
+            Block_ = done;
+            return;
+        }
+
+        if (type->IsVariant()) {
+            auto varType = static_cast<TVariantType*>(type);
+            const auto isOneByte = ConstantInt::get(Type::getInt8Ty(context), varType->GetAlternativesCount() < 256);
+            const auto data = CallInst::Create(module.getFunction("ReadVariantData"), { buf, isOneByte }, "data", Block_);
+            
+            std::function<TType*(size_t)> getType;
+            std::function<void(size_t, size_t)> genLR = [&] (size_t l, size_t r){
+                size_t m = (l + r) >> 1;
+                if (l == r) {
+                    GenerateSkip(buf, getType(m), nativeYtTypeFlags);
+                    return;
+                }
+                auto fn = std::to_string(l) + "_" + std::to_string(r);
+                const auto currIdx = ConstantInt::get(Type::getInt16Ty(context), m);
+                const auto isCurrent = CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_ULE, data, currIdx, "isUs" + fn, Block_);
+                auto lessEq = BasicBlock::Create(context, "le" + fn, Func_);
+                auto greater = BasicBlock::Create(context, "g" + fn, Func_);
+                auto out = BasicBlock::Create(context, "o" + fn, Func_);
+                BranchInst::Create(lessEq, greater, isCurrent, Block_);
+                {
+                    Block_ = lessEq;
+                    genLR(l, m);
+                    BranchInst::Create(out, Block_);
+                }
+                {
+                    Block_ = greater;
+                    genLR(m + 1, r);
+                    BranchInst::Create(out, Block_);
+                }
+                Block_ = out;
+            };
+
+            size_t elemCount = 0;
+            if (varType->GetUnderlyingType()->IsTuple()) {
+                auto tupleType = static_cast<TTupleType*>(varType->GetUnderlyingType());
+                elemCount = tupleType->GetElementsCount();
+                getType = [tupleType=tupleType] (size_t i) {
+                    return tupleType->GetElementType(i);
+                };
+            } else {
+                auto structType = static_cast<TStructType*>(varType->GetUnderlyingType());
+                
+                const std::vector<size_t>* reorder = nullptr;
+                if (auto cookie = structType->GetCookie()) {
+                    reorder = ((const std::vector<size_t>*)cookie);
+                }
+
+                elemCount = structType->GetMembersCount();
+
+                getType = [reorder = reorder, structType=structType] (size_t i) {
+                    return structType->GetMemberType(reorder ? reorder->at(i) : i);
+                };
+            }
+            genLR(0, elemCount - 1);
+            return;
+        }
+
+        if (type->IsVoid()) {
+            return;
+        }
+
+        if (type->IsNull()) {
+            return;
+        }
+
+        if (type->IsEmptyList() || type->IsEmptyDict()) {
+            return;
+        }
+
+        if (type->IsDict()) {
+            auto dictType = static_cast<TDictType*>(type);
+            auto keyType = dictType->GetKeyType();
+            auto payloadType = dictType->GetPayloadType();
+            const auto done = BasicBlock::Create(context, "done", Func_);
+
+            const auto innerSkip = BasicBlock::Create(context, "innerSkip", Func_);
+
+            const auto listContinue = BasicBlock::Create(context, "listContinue", Func_);
+
+            const auto listEndMarker = ConstantInt::get(Type::getInt8Ty(context), 0xFF);
+
+            BranchInst::Create(listContinue, Block_);
+
+            {
+                Block_ = innerSkip;
+                GenerateSkip(buf, keyType, nativeYtTypeFlags);
+                GenerateSkip(buf, payloadType, nativeYtTypeFlags);
+                BranchInst::Create(listContinue, Block_);
+            }
+            {
+                Block_ = listContinue;
+                const auto marker = CallInst::Create(module.getFunction("ReadOptional"), { buf }, "optMarker", Block_);
+                const auto check = CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_EQ, marker, listEndMarker, "exists", Block_);
+                BranchInst::Create(done, innerSkip, check, Block_);
+            }
+
+            Block_ = done;
+            return;
         }
+        
+        YQL_ENSURE(false, "Unsupported type for skip: " << type->GetKindAsStr());
     }
 
 private:
diff --git a/ydb/library/yql/providers/yt/codec/yt_codec_io.cpp b/ydb/library/yql/providers/yt/codec/yt_codec_io.cpp
index 9268ecf4a0b..450ade03b6e 100644
--- a/ydb/library/yql/providers/yt/codec/yt_codec_io.cpp
+++ b/ydb/library/yql/providers/yt/codec/yt_codec_io.cpp
@@ -2,6 +2,7 @@
 
 #include <ydb/library/yql/providers/common/codec/yql_restricted_yson.h>
 #include <ydb/library/yql/providers/common/codec/yql_codec_type_flags.h>
+#include <ydb/library/yql/providers/common/codec/yql_codec.h>
 #include <ydb/library/yql/providers/yt/common/yql_names.h>
 #ifndef MKQL_DISABLE_CODEGEN
 #include <ydb/library/yql/providers/yt/codec/codegen/yt_codec_cg.h>
@@ -913,19 +914,28 @@ protected:
         case TType::EKind::Variant: {
             auto varType = static_cast<TVariantType*>(type);
             CHECK_EXPECTED(cmd, BeginListSymbol);
-            EXPECTED(Buf_, Uint64Marker);
-            ui64 index = Buf_.ReadVarUI64();
-            YQL_ENSURE(index < varType->GetAlternativesCount(), "Bad variant alternative: " << index << ", only " <<
-                varType->GetAlternativesCount() << " are available");
+            cmd = Buf_.Read();
+            YQL_ENSURE(cmd == Int64Marker || cmd == Uint64Marker, "Excepted [U]Int64 marker, but got: " << int(cmd));
             auto underlyingType = varType->GetUnderlyingType();
             YQL_ENSURE(underlyingType->IsTuple() || underlyingType->IsStruct(), "Wrong underlying type");
             TType* itemType;
+            i64 index;
+
+            if (cmd == Int64Marker) {
+                index = Buf_.ReadVarI64();
+            } else {
+                index = Buf_.ReadVarUI64();
+            }
+
+            YQL_ENSURE(index > -1 && index < varType->GetAlternativesCount(), "Bad variant alternative: " << index << ", only " <<
+                varType->GetAlternativesCount() << " are available");
             if (underlyingType->IsTuple()) {
                 itemType = static_cast<TTupleType*>(underlyingType)->GetElementType(index);
             } else {
                 itemType = static_cast<TStructType*>(underlyingType)->GetMemberType(index);
             }
 
+
             EXPECTED(Buf_, ListItemSeparatorSymbol);
             cmd = Buf_.Read();
             SkipValue(itemType, cmd);
@@ -1004,18 +1014,42 @@ protected:
 
         case TType::EKind::Struct: {
             auto structType = static_cast<TStructType*>(type);
-            CHECK_EXPECTED(cmd, BeginListSymbol);
-            cmd = Buf_.Read();
+            YQL_ENSURE(cmd == BeginMapSymbol || cmd == BeginListSymbol);
+            if (cmd == BeginListSymbol) {
+                cmd = Buf_.Read();
+                for (ui32 i = 0; i < structType->GetMembersCount(); ++i) {
+                    SkipValue(structType->GetMemberType(i), cmd);
 
+                    cmd = Buf_.Read();
+                    if (cmd == ListItemSeparatorSymbol) {
+                        cmd = Buf_.Read();
+                    }
+                }
+                CHECK_EXPECTED(cmd, EndMapSymbol);
+                break;
+            }
+
+            cmd = Buf_.Read();
             for (ui32 i = 0; i < structType->GetMembersCount(); ++i) {
-                SkipValue(structType->GetMemberType(i), cmd);
+                CHECK_EXPECTED(cmd, StringMarker);
+                const i32 length = Buf_.ReadVarI32();
+                CHECK_STRING_LENGTH(length);
+                TString name(length, '\0');
+                Buf_.ReadMany((char*)name.data(), length);
+                cmd = Buf_.Read();
+                CHECK_EXPECTED(cmd, KeyValueSeparatorSymbol);
+
+                auto idx = structType->FindMemberIndex(name);
+                YQL_ENSURE(idx);
+                cmd = Buf_.Read();
+                SkipValue(structType->GetMemberType(*idx), cmd);
 
                 cmd = Buf_.Read();
                 if (cmd == ListItemSeparatorSymbol) {
                     cmd = Buf_.Read();
                 }
             }
-            CHECK_EXPECTED(cmd, EndListSymbol);
+            CHECK_EXPECTED(cmd, EndMapSymbol);
             break;
         }
 
@@ -1331,89 +1365,7 @@ protected:
     }
 
     void SkipSkiffField(TType* type, ui64 nativeYtTypeFlags) {
-        const bool isOptional = type->IsOptional();
-        TType* uwrappedType = type;
-        if (type->IsOptional()) {
-            uwrappedType = static_cast<TOptionalType*>(type)->GetItemType();
-        }
-
-        if (isOptional) {
-            auto marker = Buf_.Read();
-            if (!marker) {
-                return;
-            }
-        }
-
-        if (uwrappedType->IsData()) {
-            auto schemeType = static_cast<TDataType*>(uwrappedType)->GetSchemeType();
-            switch (schemeType) {
-            case NUdf::TDataType<bool>::Id:
-                Buf_.SkipMany(sizeof(ui8));
-                break;
-
-            case NUdf::TDataType<ui8>::Id:
-            case NUdf::TDataType<ui16>::Id:
-            case NUdf::TDataType<ui32>::Id:
-            case NUdf::TDataType<ui64>::Id:
-            case NUdf::TDataType<NUdf::TDate>::Id:
-            case NUdf::TDataType<NUdf::TDatetime>::Id:
-            case NUdf::TDataType<NUdf::TTimestamp>::Id:
-                Buf_.SkipMany(sizeof(ui64));
-                break;
-
-            case NUdf::TDataType<i8>::Id:
-            case NUdf::TDataType<i16>::Id:
-            case NUdf::TDataType<i32>::Id:
-            case NUdf::TDataType<i64>::Id:
-            case NUdf::TDataType<NUdf::TInterval>::Id:
-                Buf_.SkipMany(sizeof(i64));
-                break;
-
-            case NUdf::TDataType<float>::Id:
-            case NUdf::TDataType<double>::Id:
-                Buf_.SkipMany(sizeof(double));
-                break;
-
-            case NUdf::TDataType<NUdf::TUtf8>::Id:
-            case NUdf::TDataType<char*>::Id:
-            case NUdf::TDataType<NUdf::TJson>::Id:
-            case NUdf::TDataType<NUdf::TYson>::Id:
-            case NUdf::TDataType<NUdf::TUuid>::Id:
-            case NUdf::TDataType<NUdf::TDyNumber>::Id:
-            case NUdf::TDataType<NUdf::TTzDate>::Id:
-            case NUdf::TDataType<NUdf::TTzDatetime>::Id:
-            case NUdf::TDataType<NUdf::TTzTimestamp>::Id:
-            case NUdf::TDataType<NUdf::TJsonDocument>::Id: {
-                ui32 size;
-                Buf_.ReadMany((char*)&size, sizeof(size));
-                CHECK_STRING_LENGTH_UNSIGNED(size);
-                Buf_.SkipMany(size);
-                break;
-            }
-            case NUdf::TDataType<NUdf::TDecimal>::Id: {
-                if (nativeYtTypeFlags & NTCF_DECIMAL) {
-                    auto const params = static_cast<TDataDecimalType*>(type)->GetParams();
-                    if (params.first < 10) {
-                        Buf_.SkipMany(sizeof(i32));
-                    } else if (params.first < 19) {
-                        Buf_.SkipMany(sizeof(i64));
-                    } else {
-                        Buf_.SkipMany(sizeof(NDecimal::TInt128));
-                    }
-                } else {
-                    ui32 size;
-                    Buf_.ReadMany((char*)&size, sizeof(size));
-                    CHECK_STRING_LENGTH_UNSIGNED(size);
-                    Buf_.SkipMany(size);
-                }
-                break;
-            }
-            default:
-                YQL_ENSURE(false, "Unsupported data type: " << schemeType);
-            }
-        } else {
-            ythrow yexception() << "Skip of complex types is not supported";
-        }
+        return NCommon::SkipSkiffField(type, nativeYtTypeFlags, Buf_);
     }
 };
 
diff --git a/ydb/library/yql/sql/pg_dummy/pg_sql_dummy.cpp b/ydb/library/yql/sql/pg_dummy/pg_sql_dummy.cpp
index 93872431c6a..b198d61f18c 100644
--- a/ydb/library/yql/sql/pg_dummy/pg_sql_dummy.cpp
+++ b/ydb/library/yql/sql/pg_dummy/pg_sql_dummy.cpp
@@ -92,6 +92,12 @@ NUdf::TUnboxedValue ReadYsonValuePg(NKikimr::NMiniKQL::TPgType* type, char cmd,
     throw yexception() << "ReadYsonValuePg: PG types are not supported";
 }
 
+void SkipSkiffPg(NKikimr::NMiniKQL::TPgType* type, NCommon::TInputBuf& buf) {
+    Y_UNUSED(type);
+    Y_UNUSED(buf);
+    throw yexception() << "SkipSkiffPg: PG types are not supported";
+}
+
 NKikimr::NUdf::TUnboxedValue ReadSkiffPg(NKikimr::NMiniKQL::TPgType* type, NCommon::TInputBuf& buf) {
     Y_UNUSED(type);
     Y_UNUSED(buf);