diff --git a/src/IO/AsynchronousWriteBuffer.h b/src/IO/AsynchronousWriteBuffer.h
deleted file mode 100644
index 8c44f8c7d4a..00000000000
--- a/src/IO/AsynchronousWriteBuffer.h
+++ /dev/null
@@ -1,71 +0,0 @@
-#pragma once
-
-#include <vector>
-#include <Common/ThreadPool.h>
-#include <Common/MemoryTracker.h>
-#include <IO/WriteBuffer.h>
-
-
-namespace DB
-{
-
-
-/** Writes data asynchronously using double buffering.
-  */
-class AsynchronousWriteBuffer : public WriteBuffer
-{
-private:
-    WriteBuffer & out;               /// The main buffer, responsible for writing data.
-    std::vector <char> memory;       /// A piece of memory for duplicating the buffer.
-    ThreadPool pool;                 /// For asynchronous data writing.
-    bool started;                    /// Has an asynchronous data write started?
-
-    /// Swap the main and duplicate buffers.
-    void swapBuffers()
-    {
-        swap(out);
-    }
-
-    void nextImpl() override
-    {
-        if (!offset())
-            return;
-
-        if (started)
-            pool.wait();
-        else
-            started = true;
-
-        swapBuffers();
-
-        /// The data will be written in separate stream.
-        pool.scheduleOrThrowOnError([this] { thread(); });
-    }
-
-public:
-    AsynchronousWriteBuffer(WriteBuffer & out_) : WriteBuffer(nullptr, 0), out(out_), memory(out.buffer().size()), pool(1), started(false)
-    {
-        /// Data is written to the duplicate buffer.
-        set(memory.data(), memory.size());
-    }
-
-    ~AsynchronousWriteBuffer() override
-    {
-        /// FIXME move final flush into the caller
-        MemoryTracker::LockExceptionInThread lock;
-
-        if (started)
-            pool.wait();
-
-        swapBuffers();
-        out.next();
-    }
-
-    /// That is executed in a separate thread
-    void thread()
-    {
-        out.next();
-    }
-};
-
-}
diff --git a/src/IO/HexWriteBuffer.cpp b/src/IO/HexWriteBuffer.cpp
deleted file mode 100644
index 4e3403ba74b..00000000000
--- a/src/IO/HexWriteBuffer.cpp
+++ /dev/null
@@ -1,30 +0,0 @@
-#include <common/types.h>
-#include <Common/hex.h>
-#include <Common/MemoryTracker.h>
-#include <IO/HexWriteBuffer.h>
-
-
-namespace DB
-{
-
-void HexWriteBuffer::nextImpl()
-{
-    if (!offset())
-        return;
-
-    for (Position p = working_buffer.begin(); p != pos; ++p)
-    {
-        UInt8 byte = *p;
-        out.write(hexDigitUppercase(byte / 16));
-        out.write(hexDigitUppercase(byte % 16));
-    }
-}
-
-HexWriteBuffer::~HexWriteBuffer()
-{
-    /// FIXME move final flush into the caller
-    MemoryTracker::LockExceptionInThread lock;
-    nextImpl();
-}
-
-}
diff --git a/src/IO/HexWriteBuffer.h b/src/IO/HexWriteBuffer.h
deleted file mode 100644
index a68dd29065b..00000000000
--- a/src/IO/HexWriteBuffer.h
+++ /dev/null
@@ -1,28 +0,0 @@
-#pragma once
-
-#include <IO/WriteBuffer.h>
-
-
-/// Since HexWriteBuffer is often created in the inner loop, we'll make its buffer size small.
-#define DBMS_HEX_WRITE_BUFFER_SIZE 32
-
-
-namespace DB
-{
-
-/** Everything that is written into it, translates to HEX (in capital letters) and writes to another WriteBuffer.
-  */
-class HexWriteBuffer final : public WriteBuffer
-{
-protected:
-    char buf[DBMS_HEX_WRITE_BUFFER_SIZE]; //-V730
-    WriteBuffer & out;
-
-    void nextImpl() override;
-
-public:
-    HexWriteBuffer(WriteBuffer & out_) : WriteBuffer(buf, sizeof(buf)), out(out_) {}
-    ~HexWriteBuffer() override;
-};
-
-}
diff --git a/src/IO/tests/CMakeLists.txt b/src/IO/tests/CMakeLists.txt
index fcd59d94cb0..79800d8339c 100644
--- a/src/IO/tests/CMakeLists.txt
+++ b/src/IO/tests/CMakeLists.txt
@@ -25,9 +25,6 @@ target_link_libraries (var_uint PRIVATE clickhouse_common_io)
 add_executable (read_escaped_string read_escaped_string.cpp)
 target_link_libraries (read_escaped_string PRIVATE clickhouse_common_io)
 
-add_executable (async_write async_write.cpp)
-target_link_libraries (async_write PRIVATE dbms)
-
 add_executable (parse_int_perf parse_int_perf.cpp)
 target_link_libraries (parse_int_perf PRIVATE clickhouse_common_io)
 
diff --git a/src/IO/tests/async_write.cpp b/src/IO/tests/async_write.cpp
deleted file mode 100644
index e3bff7cf341..00000000000
--- a/src/IO/tests/async_write.cpp
+++ /dev/null
@@ -1,26 +0,0 @@
-#include <iostream>
-
-#include <IO/ReadBufferFromFileDescriptor.h>
-#include <IO/WriteBufferFromFileDescriptor.h>
-#include <IO/AsynchronousWriteBuffer.h>
-#include <IO/copyData.h>
-#include <Compression/CompressedWriteBuffer.h>
-
-
-int main(int, char **)
-try
-{
-    DB::ReadBufferFromFileDescriptor in1(STDIN_FILENO);
-    DB::WriteBufferFromFileDescriptor out1(STDOUT_FILENO);
-    DB::AsynchronousWriteBuffer out2(out1);
-    DB::CompressedWriteBuffer out3(out2);
-
-    DB::copyData(in1, out3);
-
-    return 0;
-}
-catch (const DB::Exception & e)
-{
-    std::cerr << e.what() << ", " << e.displayText() << std::endl;
-    return 1;
-}
diff --git a/src/IO/tests/parse_int_perf.cpp b/src/IO/tests/parse_int_perf.cpp
index 93f49d80258..e35a3d8a857 100644
--- a/src/IO/tests/parse_int_perf.cpp
+++ b/src/IO/tests/parse_int_perf.cpp
@@ -62,7 +62,6 @@ int main(int argc, char ** argv)
         {
             DB::WriteBufferFromVector wb(formatted);
         //    DB::CompressedWriteBuffer wb2(wb1);
-        //    DB::AsynchronousWriteBuffer wb(wb2);
             Stopwatch watch;
 
             UInt64 tsc = rdtsc();
diff --git a/src/IO/ya.make b/src/IO/ya.make
index 980719aa74f..6605cf64277 100644
--- a/src/IO/ya.make
+++ b/src/IO/ya.make
@@ -29,7 +29,6 @@ SRCS(
     HTTPChunkedReadBuffer.cpp
     HTTPCommon.cpp
     HashingWriteBuffer.cpp
-    HexWriteBuffer.cpp
     LZMADeflatingWriteBuffer.cpp
     LZMAInflatingReadBuffer.cpp
     LimitReadBuffer.cpp
diff --git a/src/Interpreters/Cluster.cpp b/src/Interpreters/Cluster.cpp
index c9c56c96cbe..fb9788e84c4 100644
--- a/src/Interpreters/Cluster.cpp
+++ b/src/Interpreters/Cluster.cpp
@@ -6,7 +6,6 @@
 #include <Common/StringUtils/StringUtils.h>
 #include <Common/parseAddress.h>
 #include <Core/Settings.h>
-#include <IO/HexWriteBuffer.h>
 #include <IO/WriteHelpers.h>
 #include <IO/ReadHelpers.h>
 #include <Poco/Util/AbstractConfiguration.h>
diff --git a/src/Storages/MergeTree/MergeTreeData.cpp b/src/Storages/MergeTree/MergeTreeData.cpp
index 2d841b98c59..d9e24581c0c 100644
--- a/src/Storages/MergeTree/MergeTreeData.cpp
+++ b/src/Storages/MergeTree/MergeTreeData.cpp
@@ -13,7 +13,6 @@
 #include <Functions/FunctionFactory.h>
 #include <Functions/IFunction.h>
 #include <IO/ConcatReadBuffer.h>
-#include <IO/HexWriteBuffer.h>
 #include <IO/Operators.h>
 #include <IO/ReadBufferFromMemory.h>
 #include <IO/WriteBufferFromString.h>