Adjust range reader for remote fs reads

src/Common/ProfileEvents.cpp

@@ -262,6 +262,7 @@
     M(RemoteFSNewReaders, "Number of created impl objects") \
     M(RemoteFSAsyncBuffers, "Total number of AsycnhronousReadIndirectBufferFromREmoteFS buffers") \
     M(RemoteFSSimpleBuffers, "Total number of ReadIndirectBufferFromREmoteFS buffers") \
+    M(RemoteFSRedundantlyReadBytes, "") \
     \
     M(SleepFunctionCalls, "Number of times a sleep function (sleep, sleepEachRow) has been called.") \
     M(SleepFunctionMicroseconds, "Time spent sleeping due to a sleep function call.") \

src/Compression/CachedCompressedReadBuffer.cpp

@@ -28,6 +28,12 @@ void CachedCompressedReadBuffer::initInput()
 }
 
 
+void CachedCompressedReadBuffer::prefetch()
+{
+    file_in->prefetch();
+}
+
+
 bool CachedCompressedReadBuffer::nextImpl()
 {
     /// Let's check for the presence of a decompressed block in the cache, grab the ownership of this block, if it exists.

src/Compression/CachedCompressedReadBuffer.h

@@ -33,8 +33,11 @@ private:
     UncompressedCache::MappedPtr owned_cell;
 
     void initInput();
+
     bool nextImpl() override;
 
+    void prefetch() override;
+
     /// Passed into file_in.
     ReadBufferFromFileBase::ProfileCallback profile_callback;
     clockid_t clock_type {};

src/Compression/CompressedReadBufferBase.cpp

@@ -11,6 +11,7 @@
 #include <IO/ReadBuffer.h>
 #include <IO/BufferWithOwnMemory.h>
 #include <Compression/CompressionInfo.h>
+#include <IO/AsynchronousReadIndirectBufferFromRemoteFS.h>
 #include <IO/WriteHelpers.h>
 #include <IO/Operators.h>
 
@@ -107,6 +108,13 @@ static void validateChecksum(char * data, size_t size, const Checksum expected_c
 }
 
 
+void CompressedReadBufferBase::setRightOffset(size_t offset)
+{
+    if (auto * async_in = dynamic_cast<AsynchronousReadIndirectBufferFromRemoteFS *>(compressed_in))
+        async_in->setRightOffset(offset);
+}
+
+
 /// Read compressed data into compressed_buffer. Get size of decompressed data from block header. Checksum if need.
 /// Returns number of compressed bytes read.
 size_t CompressedReadBufferBase::readCompressedData(size_t & size_decompressed, size_t & size_compressed_without_checksum, bool always_copy)

src/Compression/CompressedReadBufferBase.h

@@ -60,6 +60,12 @@ public:
         disable_checksum = true;
     }
 
+    /**
+     * For asynchronous range reading from remote fs need to update last offset for current task,
+     * when newer tasks read behind previous task last mark.
+     */
+    void setRightOffset(size_t offset);
+
 public:
     CompressionCodecPtr codec;
 };

src/Compression/CompressedReadBufferFromFile.cpp

@@ -44,12 +44,6 @@ bool CompressedReadBufferFromFile::nextImpl()
 }
 
 
-void CompressedReadBufferFromFile::prefetch()
-{
-    file_in.prefetch();
-}
-
-
 CompressedReadBufferFromFile::CompressedReadBufferFromFile(std::unique_ptr<ReadBufferFromFileBase> buf, bool allow_different_codecs_)
     : BufferWithOwnMemory<ReadBuffer>(0), p_file_in(std::move(buf)), file_in(*p_file_in)
 {
@@ -72,6 +66,12 @@ CompressedReadBufferFromFile::CompressedReadBufferFromFile(
 }
 
 
+void CompressedReadBufferFromFile::prefetch()
+{
+    file_in.prefetch();
+}
+
+
 void CompressedReadBufferFromFile::seek(size_t offset_in_compressed_file, size_t offset_in_decompressed_block)
 {
     /// Nothing to do if we already at required position

src/Compression/CompressedReadBufferFromFile.h

@@ -42,6 +42,7 @@ private:
     /* size_t nextimpl_working_buffer_offset; */
 
     bool nextImpl() override;
+
     void prefetch() override;
 
 public:
@@ -61,6 +62,7 @@ public:
     {
         file_in.setProfileCallback(profile_callback_, clock_type_);
     }
+
 };
 
 }

src/Disks/DiskWebServer.cpp

@@ -168,7 +168,7 @@ std::unique_ptr<ReadBufferFromFileBase> DiskWebServer::readFile(const String & p
 
     bool threadpool_read = read_settings.remote_fs_method == RemoteFSReadMethod::read_threadpool;
 
-    auto web_impl = std::make_unique<ReadBufferFromWebServerGather>(url, meta, getContext(), threadpool_read, read_settings);
+    auto web_impl = std::make_unique<ReadBufferFromWebServerGather>(path, url, meta, getContext(), threadpool_read, read_settings);
 
     if (threadpool_read)
     {

src/Disks/HDFS/DiskHDFS.cpp

@@ -73,7 +73,7 @@ std::unique_ptr<ReadBufferFromFileBase> DiskHDFS::readFile(const String & path,
         "Read from file by path: {}. Existing HDFS objects: {}",
         backQuote(metadata_path + path), metadata.remote_fs_objects.size());
 
-    auto hdfs_impl = std::make_unique<ReadBufferFromHDFSGather>(config, remote_fs_root_path, metadata, read_settings.remote_fs_buffer_size);
+    auto hdfs_impl = std::make_unique<ReadBufferFromHDFSGather>(path, config, remote_fs_root_path, metadata, read_settings.remote_fs_buffer_size);
 
     if (read_settings.remote_fs_method == RemoteFSReadMethod::read_threadpool)
     {

src/Disks/ReadBufferFromRemoteFSGather.cpp

@@ -12,6 +12,7 @@
 #include <Storages/HDFS/ReadBufferFromHDFS.h>
 #endif
 
+#include <base/logger_useful.h>
 #include <filesystem>
 #include <iostream>
 
@@ -27,31 +28,32 @@ namespace ErrorCodes
 
 
 #if USE_AWS_S3
-SeekableReadBufferPtr ReadBufferFromS3Gather::createImplementationBuffer(const String & path) const
+SeekableReadBufferPtr ReadBufferFromS3Gather::createImplementationBuffer(const String & path, size_t last_offset) const
 {
     return std::make_unique<ReadBufferFromS3>(client_ptr, bucket,
-        fs::path(metadata.remote_fs_root_path) / path, max_single_read_retries, settings, threadpool_read);
+        fs::path(metadata.remote_fs_root_path) / path, max_single_read_retries, settings, threadpool_read, last_offset);
 }
 #endif
 
 
-SeekableReadBufferPtr ReadBufferFromWebServerGather::createImplementationBuffer(const String & path) const
+SeekableReadBufferPtr ReadBufferFromWebServerGather::createImplementationBuffer(const String & path, size_t last_offset) const
 {
-    return std::make_unique<ReadBufferFromWebServer>(fs::path(uri) / path, context, settings, threadpool_read);
+    return std::make_unique<ReadBufferFromWebServer>(fs::path(uri) / path, context, settings, threadpool_read, last_offset);
 }
 
 
 #if USE_HDFS
-SeekableReadBufferPtr ReadBufferFromHDFSGather::createImplementationBuffer(const String & path) const
+SeekableReadBufferPtr ReadBufferFromHDFSGather::createImplementationBuffer(const String & path, size_t last_offset) const
 {
-    return std::make_unique<ReadBufferFromHDFS>(hdfs_uri, fs::path(hdfs_directory) / path, config, buf_size);
+    return std::make_unique<ReadBufferFromHDFS>(hdfs_uri, fs::path(hdfs_directory) / path, config, buf_size, last_offset);
 }
 #endif
 
 
-ReadBufferFromRemoteFSGather::ReadBufferFromRemoteFSGather(const RemoteMetadata & metadata_)
+ReadBufferFromRemoteFSGather::ReadBufferFromRemoteFSGather(const RemoteMetadata & metadata_, const String & path_)
     : ReadBuffer(nullptr, 0)
     , metadata(metadata_)
+    , path(path_)
 {
 }
 
@@ -91,7 +93,7 @@ void ReadBufferFromRemoteFSGather::initialize()
             /// Do not create a new buffer if we already have what we need.
             if (!current_buf || buf_idx != i)
             {
-                current_buf = createImplementationBuffer(file_path);
+                current_buf = createImplementationBuffer(file_path, last_offset);
                 buf_idx = i;
             }
 
@@ -126,8 +128,8 @@ bool ReadBufferFromRemoteFSGather::nextImpl()
 
     ++current_buf_idx;
 
-    const auto & path = metadata.remote_fs_objects[current_buf_idx].first;
+    const auto & current_path = metadata.remote_fs_objects[current_buf_idx].first;
-    current_buf = createImplementationBuffer(path);
+    current_buf = createImplementationBuffer(current_path, last_offset);
 
     return readImpl();
 }
@@ -145,6 +147,7 @@ bool ReadBufferFromRemoteFSGather::readImpl()
     if (bytes_to_ignore)
         current_buf->ignore(bytes_to_ignore);
 
+    LOG_DEBUG(&Poco::Logger::get("Gather"), "Reading from path: {}", path);
     auto result = current_buf->next();
 
     swap(*current_buf);
@@ -158,8 +161,17 @@ bool ReadBufferFromRemoteFSGather::readImpl()
 
 void ReadBufferFromRemoteFSGather::seek(off_t offset)
 {
+    current_buf.reset();
     absolute_position = offset;
-    initialize();
+    // initialize();
+}
+
+
+void ReadBufferFromRemoteFSGather::setRightOffset(size_t offset)
+{
+    assert(last_offset < offset);
+    current_buf.reset();
+    last_offset = offset;
 }
 
 
@@ -168,4 +180,13 @@ void ReadBufferFromRemoteFSGather::reset()
     current_buf.reset();
 }
 
+
+String ReadBufferFromRemoteFSGather::getFileName() const
+{
+    return path;
+    // if (current_buf)
+    //     return fs::path(metadata.metadata_file_path) / metadata.remote_fs_objects[buf_idx].first;
+    // return metadata.metadata_file_path;
+}
+
 }

src/Disks/ReadBufferFromRemoteFSGather.h

@@ -13,28 +13,31 @@ namespace Aws
 namespace S3
 {
 class S3Client;
-}}
+}
+}
+
 namespace DB
 {
 
 class ReadBufferFromRemoteFSGather : public ReadBuffer
 {
-friend class ThreadPoolRemoteFSReader;
 friend class ReadIndirectBufferFromRemoteFS;
 
 public:
-    explicit ReadBufferFromRemoteFSGather(const RemoteMetadata & metadata_);
+    explicit ReadBufferFromRemoteFSGather(const RemoteMetadata & metadata_, const String & path_);
 
-    String getFileName() const { return metadata.metadata_file_path; }
+    String getFileName() const;
 
     void reset();
 
     void seek(off_t offset); /// SEEK_SET only.
 
-protected:
+    void setRightOffset(size_t offset);
+
     size_t readInto(char * data, size_t size, size_t offset, size_t ignore = 0);
 
-    virtual SeekableReadBufferPtr createImplementationBuffer(const String & path) const = 0;
+protected:
+    virtual SeekableReadBufferPtr createImplementationBuffer(const String & path, size_t last_offset) const = 0;
 
     RemoteMetadata metadata;
 
@@ -54,6 +57,10 @@ private:
     size_t buf_idx = 0;
 
     size_t bytes_to_ignore = 0;
+
+    size_t last_offset = 0;
+
+    String path;
 };
 
 
@@ -63,13 +70,14 @@ class ReadBufferFromS3Gather final : public ReadBufferFromRemoteFSGather
 {
 public:
     ReadBufferFromS3Gather(
+        const String & path_,
         std::shared_ptr<Aws::S3::S3Client> client_ptr_,
         const String & bucket_,
         IDiskRemote::Metadata metadata_,
         size_t max_single_read_retries_,
         const ReadSettings & settings_,
         bool threadpool_read_ = false)
-        : ReadBufferFromRemoteFSGather(metadata_)
+        : ReadBufferFromRemoteFSGather(metadata_, path_)
         , client_ptr(std::move(client_ptr_))
         , bucket(bucket_)
         , max_single_read_retries(max_single_read_retries_)
@@ -78,7 +86,7 @@ public:
     {
     }
 
-    SeekableReadBufferPtr createImplementationBuffer(const String & path) const override;
+    SeekableReadBufferPtr createImplementationBuffer(const String & path, size_t last_offset) const override;
 
 private:
     std::shared_ptr<Aws::S3::S3Client> client_ptr;
@@ -94,12 +102,13 @@ class ReadBufferFromWebServerGather final : public ReadBufferFromRemoteFSGather
 {
 public:
     ReadBufferFromWebServerGather(
+            const String & path_,
             const String & uri_,
             RemoteMetadata metadata_,
             ContextPtr context_,
             size_t threadpool_read_,
             const ReadSettings & settings_)
-        : ReadBufferFromRemoteFSGather(metadata_)
+        : ReadBufferFromRemoteFSGather(metadata_, path_)
         , uri(uri_)
         , context(context_)
         , threadpool_read(threadpool_read_)
@@ -107,7 +116,7 @@ public:
     {
     }
 
-    SeekableReadBufferPtr createImplementationBuffer(const String & path) const override;
+    SeekableReadBufferPtr createImplementationBuffer(const String & path, size_t last_offset) const override;
 
 private:
     String uri;
@@ -123,11 +132,12 @@ class ReadBufferFromHDFSGather final : public ReadBufferFromRemoteFSGather
 {
 public:
     ReadBufferFromHDFSGather(
+            const String & path_,
             const Poco::Util::AbstractConfiguration & config_,
             const String & hdfs_uri_,
             IDiskRemote::Metadata metadata_,
             size_t buf_size_)
-        : ReadBufferFromRemoteFSGather(metadata_)
+        : ReadBufferFromRemoteFSGather(metadata_, path_)
         , config(config_)
         , buf_size(buf_size_)
     {
@@ -136,7 +146,7 @@ public:
         hdfs_uri = hdfs_uri_.substr(0, begin_of_path);
     }
 
-    SeekableReadBufferPtr createImplementationBuffer(const String & path) const override;
+    SeekableReadBufferPtr createImplementationBuffer(const String & path, size_t last_offset) const override;
 
 private:
     const Poco::Util::AbstractConfiguration & config;

src/Disks/S3/DiskS3.cpp

@@ -205,6 +205,7 @@ std::unique_ptr<ReadBufferFromFileBase> DiskS3::readFile(const String & path, co
     bool threadpool_read = read_settings.remote_fs_method == RemoteFSReadMethod::read_threadpool;
 
     auto s3_impl = std::make_unique<ReadBufferFromS3Gather>(
+        path,
         settings->client, bucket, metadata,
         settings->s3_max_single_read_retries, read_settings, threadpool_read);
 

src/Disks/S3/registerDiskS3.cpp

@@ -200,27 +200,27 @@ void registerDiskS3(DiskFactory & factory)
 
         s3disk->startup();
 
-        bool cache_enabled = config.getBool(config_prefix + ".cache_enabled", true);
+        // bool cache_enabled = config.getBool(config_prefix + ".cache_enabled", true);
 
-        if (cache_enabled)
+        // if (cache_enabled)
-        {
+        // {
-            String cache_path = config.getString(config_prefix + ".cache_path", context->getPath() + "disks/" + name + "/cache/");
+        //     String cache_path = config.getString(config_prefix + ".cache_path", context->getPath() + "disks/" + name + "/cache/");
 
-            if (metadata_path == cache_path)
+        //     if (metadata_path == cache_path)
-                throw Exception("Metadata and cache path should be different: " + metadata_path, ErrorCodes::BAD_ARGUMENTS);
+        //         throw Exception("Metadata and cache path should be different: " + metadata_path, ErrorCodes::BAD_ARGUMENTS);
 
-            auto cache_disk = std::make_shared<DiskLocal>("s3-cache", cache_path, 0);
+        //     auto cache_disk = std::make_shared<DiskLocal>("s3-cache", cache_path, 0);
-            auto cache_file_predicate = [] (const String & path)
+        //     auto cache_file_predicate = [] (const String & path)
-            {
+        //     {
-                return path.ends_with("idx") // index files.
+        //         return path.ends_with("idx") // index files.
-                       || path.ends_with("mrk") || path.ends_with("mrk2") || path.ends_with("mrk3") // mark files.
+        //                || path.ends_with("mrk") || path.ends_with("mrk2") || path.ends_with("mrk3") // mark files.
-                       || path.ends_with("txt") || path.ends_with("dat");
+        //                || path.ends_with("txt") || path.ends_with("dat");
-            };
+        //     };
 
-            s3disk = std::make_shared<DiskCacheWrapper>(s3disk, cache_disk, cache_file_predicate);
+        //     s3disk = std::make_shared<DiskCacheWrapper>(s3disk, cache_disk, cache_file_predicate);
-        }
+        // }
 
-        return std::make_shared<DiskRestartProxy>(s3disk);
+        return s3disk;
     };
     factory.registerDiskType("s3", creator);
 }

src/IO/AsynchronousReadIndirectBufferFromRemoteFS.cpp

@@ -2,6 +2,7 @@
 
 #include <Common/Stopwatch.h>
 #include <IO/ThreadPoolRemoteFSReader.h>
+#include <base/logger_useful.h>
 
 
 namespace CurrentMetrics
@@ -35,14 +36,16 @@ AsynchronousReadIndirectBufferFromRemoteFS::AsynchronousReadIndirectBufferFromRe
         Int32 priority_,
         std::shared_ptr<ReadBufferFromRemoteFSGather> impl_,
         size_t buf_size_,
-        size_t min_bytes_for_seek_)
+        size_t /* min_bytes_for_seek_ */)
     : ReadBufferFromFileBase(buf_size_, nullptr, 0)
     , reader(reader_)
     , priority(priority_)
     , impl(impl_)
     , prefetch_buffer(buf_size_)
-    , min_bytes_for_seek(min_bytes_for_seek_)
+    // , min_bytes_for_seek(min_bytes_for_seek_)
 {
+    ProfileEvents::increment(ProfileEvents::RemoteFSAsyncBuffers);
+    buffer_events += impl->getFileName() + " : ";
 }
 
 
@@ -66,15 +69,31 @@ std::future<IAsynchronousReader::Result> AsynchronousReadIndirectBufferFromRemot
 
 void AsynchronousReadIndirectBufferFromRemoteFS::prefetch()
 {
-    if (hasPendingData())
+     if (hasPendingData())
-        return;
+         return;
 
+     if (prefetch_future.valid())
+         return;
+
+     prefetch_future = readInto(prefetch_buffer.data(), prefetch_buffer.size());
+     ProfileEvents::increment(ProfileEvents::RemoteFSPrefetches);
+     buffer_events += "-- Prefetch (" + toString(absolute_position) + ") --";
+}
+
+
+void AsynchronousReadIndirectBufferFromRemoteFS::setRightOffset(size_t offset)
+{
+    buffer_events += "-- Set last offset " + toString(offset) + "--";
     if (prefetch_future.valid())
-        return;
+    {
+        buffer_events += "-- Cancelling because of offset update --";
+        ProfileEvents::increment(ProfileEvents::RemoteFSSeekCancelledPrefetches);
+        prefetch_future.wait();
+        prefetch_future = {};
+    }
 
-    prefetch_future = readInto(prefetch_buffer.data(), prefetch_buffer.size());
+    last_offset = offset;
-    ProfileEvents::increment(ProfileEvents::RemoteFSPrefetches);
+    impl->setRightOffset(offset);
-    buffer_events += "-- Prefetch --";
 }
 
 
@@ -86,7 +105,6 @@ bool AsynchronousReadIndirectBufferFromRemoteFS::nextImpl()
     if (prefetch_future.valid())
     {
         ProfileEvents::increment(ProfileEvents::RemoteFSPrefetchReads);
-        buffer_events += "-- Read from prefetch --";
 
         CurrentMetrics::Increment metric_increment{CurrentMetrics::AsynchronousReadWait};
         Stopwatch watch;
@@ -100,13 +118,17 @@ bool AsynchronousReadIndirectBufferFromRemoteFS::nextImpl()
                 absolute_position += size;
             }
         }
+
+        buffer_events += fmt::format("-- Read from prefetch from offset: {}, upper bound: {}, actually read: {} --",
+                                     toString(absolute_position), toString(last_offset), toString(size));
         watch.stop();
         ProfileEvents::increment(ProfileEvents::AsynchronousReadWaitMicroseconds, watch.elapsedMicroseconds());
     }
     else
     {
-        buffer_events += "-- Read without prefetch --";
         size = readInto(memory.data(), memory.size()).get();
+        buffer_events += fmt::format("-- Read without prefetch from offset: {}, upper bound: {}, actually read: {} --",
+                                     toString(absolute_position), toString(last_offset), toString(size));
         if (size)
         {
             set(memory.data(), memory.size());
@@ -115,7 +137,6 @@ bool AsynchronousReadIndirectBufferFromRemoteFS::nextImpl()
         }
     }
 
-    buffer_events += " + " + toString(size) + " + ";
     prefetch_future = {};
     return size;
 }
@@ -163,6 +184,7 @@ off_t AsynchronousReadIndirectBufferFromRemoteFS::seek(off_t offset_, int whence
 
     if (prefetch_future.valid())
     {
+        buffer_events += "-- cancelling prefetch because of seek --";
         ProfileEvents::increment(ProfileEvents::RemoteFSSeekCancelledPrefetches);
         prefetch_future.wait();
         prefetch_future = {};
@@ -170,16 +192,18 @@ off_t AsynchronousReadIndirectBufferFromRemoteFS::seek(off_t offset_, int whence
 
     pos = working_buffer.end();
 
-    if (static_cast<off_t>(absolute_position) >= getPosition()
+    // if (static_cast<off_t>(absolute_position) >= getPosition()
-        && static_cast<off_t>(absolute_position) < getPosition() + static_cast<off_t>(min_bytes_for_seek))
+    //     && static_cast<off_t>(absolute_position) < getPosition() + static_cast<off_t>(min_bytes_for_seek))
-    {
+    // {
-        /**
+    //    /**
-         * Lazy ignore. Save number of bytes to ignore and ignore it either for prefetch buffer or current buffer.
+    //     * Lazy ignore. Save number of bytes to ignore and ignore it either for prefetch buffer or current buffer.
-         */
+    //     */
-        bytes_to_ignore = absolute_position - getPosition();
+    //    // bytes_to_ignore = absolute_position - getPosition();
-    }
+    //    impl->seek(absolute_position); /// SEEK_SET.
-    else
+    // }
+    // else
     {
+        buffer_events += "-- Impl seek --";
         impl->seek(absolute_position); /// SEEK_SET.
     }
 
@@ -189,14 +213,14 @@ off_t AsynchronousReadIndirectBufferFromRemoteFS::seek(off_t offset_, int whence
 
 void AsynchronousReadIndirectBufferFromRemoteFS::finalize()
 {
-    std::cerr << "\n\n\nBuffer events: " << buffer_events << std::endl;
-
     if (prefetch_future.valid())
     {
+        buffer_events += "-- cancelling prefetch in finalize --";
         ProfileEvents::increment(ProfileEvents::RemoteFSUnusedCancelledPrefetches);
         prefetch_future.wait();
         prefetch_future = {};
     }
+    std::cerr << "Buffer events: " << buffer_events << std::endl;
 }
 
 

src/IO/AsynchronousReadIndirectBufferFromRemoteFS.h

@@ -47,6 +47,8 @@ public:
 
     void prefetch() override;
 
+    void setRightOffset(size_t offset);
+
 private:
     bool nextImpl() override;
 
@@ -68,8 +70,10 @@ private:
 
     String buffer_events;
 
-    size_t min_bytes_for_seek;
+    // size_t min_bytes_for_seek;
+
     size_t bytes_to_ignore = 0;
+    Int64 last_offset = 0;
 };
 
 }

src/IO/ReadBufferFromS3.cpp

@@ -32,7 +32,7 @@ namespace ErrorCodes
 
 ReadBufferFromS3::ReadBufferFromS3(
     std::shared_ptr<Aws::S3::S3Client> client_ptr_, const String & bucket_, const String & key_,
-    UInt64 max_single_read_retries_, const ReadSettings & settings_, bool use_external_buffer_)
+    UInt64 max_single_read_retries_, const ReadSettings & settings_, bool use_external_buffer_, size_t last_offset_)
     : SeekableReadBuffer(nullptr, 0)
     , client_ptr(std::move(client_ptr_))
     , bucket(bucket_)
@@ -40,11 +40,22 @@ ReadBufferFromS3::ReadBufferFromS3(
     , max_single_read_retries(max_single_read_retries_)
     , read_settings(settings_)
     , use_external_buffer(use_external_buffer_)
+    , last_offset(last_offset_)
 {
 }
 
 bool ReadBufferFromS3::nextImpl()
 {
+    if (last_offset)
+    {
+        if (static_cast<off_t>(last_offset) == offset)
+        {
+            impl.reset();
+            working_buffer.resize(0);
+            return false;
+        }
+    }
+
     bool next_result = false;
 
     /// `impl` has been initialized earlier and now we're at the end of the current portion of data.
@@ -162,16 +173,17 @@ std::unique_ptr<ReadBuffer> ReadBufferFromS3::initialize()
     req.SetBucket(bucket);
     req.SetKey(key);
 
-    auto right_offset = read_settings.remote_read_right_offset;
+    // auto right_offset = read_settings.remote_read_right_offset;
-    if (right_offset)
+
+    if (last_offset)
     {
-        req.SetRange(fmt::format("bytes={}-{}", offset, right_offset));
+        req.SetRange(fmt::format("bytes={}-{}", offset, last_offset - 1));
-        LOG_TRACE(log, "Read S3 object. Bucket: {}, Key: {}, Range: {}-{}", bucket, key, offset, right_offset);
+        LOG_DEBUG(log, "Read S3 object. Bucket: {}, Key: {}, Range: {}-{}", bucket, key, offset, last_offset - 1);
     }
     else
     {
         req.SetRange(fmt::format("bytes={}-", offset));
-        LOG_TRACE(log, "Read S3 object. Bucket: {}, Key: {}, Offset: {}", bucket, key, offset);
+        LOG_DEBUG(log, "Read S3 object. Bucket: {}, Key: {}, Offset: {}", bucket, key, offset);
     }
 
     Aws::S3::Model::GetObjectOutcome outcome = client_ptr->GetObject(req);

src/IO/ReadBufferFromS3.h

@@ -45,8 +45,10 @@ public:
         const String & key_,
         UInt64 max_single_read_retries_,
         const ReadSettings & settings_,
-        bool use_external_buffer = false);
+        bool use_external_buffer = false,
+        size_t last_offset_ = 0);
 
+    size_t right = 0;
     bool nextImpl() override;
 
     off_t seek(off_t off, int whence) override;
@@ -57,6 +59,7 @@ private:
 
     ReadSettings read_settings;
     bool use_external_buffer;
+    size_t last_offset;
 };
 
 }

src/IO/ReadBufferFromWebServer.cpp

@@ -23,7 +23,7 @@ namespace ErrorCodes
 static constexpr size_t HTTP_MAX_TRIES = 10;
 
 ReadBufferFromWebServer::ReadBufferFromWebServer(
-    const String & url_, ContextPtr context_, const ReadSettings & settings_, bool use_external_buffer_)
+    const String & url_, ContextPtr context_, const ReadSettings & settings_, bool use_external_buffer_, size_t)
     : SeekableReadBuffer(nullptr, 0)
     , log(&Poco::Logger::get("ReadBufferFromWebServer"))
     , context(context_)
@@ -108,7 +108,7 @@ void ReadBufferFromWebServer::initializeWithRetry()
                 if (i == num_tries - 1)
                     throw;
 
-                LOG_ERROR(&Poco::Logger::get("ReadBufferFromWeb"), e.what());
+                LOG_ERROR(&Poco::Logger::get("ReadBufferFromWeb"), "Error: {}, code: {}", e.what(), e.code());
                 sleepForMilliseconds(milliseconds_to_wait);
                 milliseconds_to_wait *= 2;
             }

src/IO/ReadBufferFromWebServer.h

@@ -20,7 +20,8 @@ public:
     explicit ReadBufferFromWebServer(
         const String & url_, ContextPtr context_,
         const ReadSettings & settings_ = {},
-        bool use_external_buffer_ = false);
+        bool use_external_buffer_ = false,
+        size_t last_offset = 0);
 
     bool nextImpl() override;
 

src/Storages/HDFS/ReadBufferFromHDFS.cpp

@@ -125,7 +125,7 @@ ReadBufferFromHDFS::ReadBufferFromHDFS(
         const String & hdfs_uri_,
         const String & hdfs_file_path_,
         const Poco::Util::AbstractConfiguration & config_,
-        size_t buf_size_)
+        size_t buf_size_, size_t)
     : SeekableReadBuffer(nullptr, 0)
     , impl(std::make_unique<ReadBufferFromHDFSImpl>(hdfs_uri_, hdfs_file_path_, config_, buf_size_))
 {

src/Storages/HDFS/ReadBufferFromHDFS.h

@@ -27,7 +27,9 @@ struct ReadBufferFromHDFSImpl;
 
 public:
     ReadBufferFromHDFS(const String & hdfs_uri_, const String & hdfs_file_path_,
-        const Poco::Util::AbstractConfiguration & config_, size_t buf_size_ = DBMS_DEFAULT_BUFFER_SIZE);
+                       const Poco::Util::AbstractConfiguration & config_,
+                       size_t buf_size_ = DBMS_DEFAULT_BUFFER_SIZE,
+                       size_t last_offset = 0);
 
     ~ReadBufferFromHDFS() override;
 

src/Storages/MergeTree/IMergeTreeReader.h

@@ -31,7 +31,8 @@ public:
 
     /// Return the number of rows has been read or zero if there is no columns to read.
     /// If continue_reading is true, continue reading from last state, otherwise seek to from_mark
-    virtual size_t readRows(size_t from_mark, bool continue_reading, size_t max_rows_to_read, Columns & res_columns) = 0;
+    virtual size_t readRows(size_t from_mark, size_t current_task_last_mark,
+                            bool continue_reading, size_t max_rows_to_read, Columns & res_columns) = 0;
 
     virtual bool canReadIncompleteGranules() const = 0;
 

src/Storages/MergeTree/MergeTreeRangeReader.cpp

@@ -55,8 +55,11 @@ static void filterColumns(Columns & columns, const ColumnPtr & filter)
 
 
 MergeTreeRangeReader::DelayedStream::DelayedStream(
-        size_t from_mark, IMergeTreeReader * merge_tree_reader_)
+    size_t from_mark,
+    size_t current_task_last_mark_,
+    IMergeTreeReader * merge_tree_reader_)
         : current_mark(from_mark), current_offset(0), num_delayed_rows(0)
+        , current_task_last_mark(current_task_last_mark_)
         , merge_tree_reader(merge_tree_reader_)
         , index_granularity(&(merge_tree_reader->data_part->index_granularity))
         , continue_reading(false), is_finished(false)
@@ -73,7 +76,8 @@ size_t MergeTreeRangeReader::DelayedStream::readRows(Columns & columns, size_t n
 {
     if (num_rows)
     {
-        size_t rows_read = merge_tree_reader->readRows(current_mark, continue_reading, num_rows, columns);
+        size_t rows_read = merge_tree_reader->readRows(
+            current_mark, current_task_last_mark, continue_reading, num_rows, columns);
         continue_reading = true;
 
         /// Zero rows_read maybe either because reading has finished
@@ -151,13 +155,13 @@ size_t MergeTreeRangeReader::DelayedStream::finalize(Columns & columns)
 
 
 MergeTreeRangeReader::Stream::Stream(
-        size_t from_mark, size_t to_mark, IMergeTreeReader * merge_tree_reader_)
+        size_t from_mark, size_t to_mark, size_t current_task_last_mark, IMergeTreeReader * merge_tree_reader_)
         : current_mark(from_mark), offset_after_current_mark(0)
         , last_mark(to_mark)
         , merge_tree_reader(merge_tree_reader_)
         , index_granularity(&(merge_tree_reader->data_part->index_granularity))
         , current_mark_index_granularity(index_granularity->getMarkRows(from_mark))
-        , stream(from_mark, merge_tree_reader)
+        , stream(from_mark, current_task_last_mark, merge_tree_reader)
 {
     size_t marks_count = index_granularity->getMarksCount();
     if (from_mark >= marks_count)
@@ -280,9 +284,9 @@ void MergeTreeRangeReader::ReadResult::adjustLastGranule()
         throw Exception("Can't adjust last granule because no granules were added.", ErrorCodes::LOGICAL_ERROR);
 
     if (num_rows_to_subtract > rows_per_granule.back())
-        throw Exception("Can't adjust last granule because it has " + toString(rows_per_granule.back())
+        throw Exception(ErrorCodes::LOGICAL_ERROR,
-                        + " rows, but try to subtract " + toString(num_rows_to_subtract) + " rows.",
+                        "Can't adjust last granule because it has {} rows, but try to subtract {} rows.",
-                        ErrorCodes::LOGICAL_ERROR);
+                        toString(rows_per_granule.back()), toString(num_rows_to_subtract));
 
     rows_per_granule.back() -= num_rows_to_subtract;
     total_rows_per_granule -= num_rows_to_subtract;
@@ -750,6 +754,16 @@ MergeTreeRangeReader::ReadResult MergeTreeRangeReader::startReadingChain(size_t
     ReadResult result;
     result.columns.resize(merge_tree_reader->getColumns().size());
 
+    auto current_task_last_mark_range = std::max_element(ranges.begin(), ranges.end(),
+        [&](const MarkRange & range1, const MarkRange & range2)
+    {
+        return range1.end < range2.end;
+    });
+
+    size_t current_task_last_mark = 0;
+    if (current_task_last_mark_range != ranges.end())
+        current_task_last_mark = current_task_last_mark_range->end;
+
     /// Stream is lazy. result.num_added_rows is the number of rows added to block which is not equal to
     /// result.num_rows_read until call to stream.finalize(). Also result.num_added_rows may be less than
     /// result.num_rows_read if the last granule in range also the last in part (so we have to adjust last granule).
@@ -760,7 +774,7 @@ MergeTreeRangeReader::ReadResult MergeTreeRangeReader::startReadingChain(size_t
             if (stream.isFinished())
             {
                 result.addRows(stream.finalize(result.columns));
-                stream = Stream(ranges.front().begin, ranges.front().end, merge_tree_reader);
+                stream = Stream(ranges.front().begin, ranges.front().end, current_task_last_mark, merge_tree_reader);
                 result.addRange(ranges.front());
                 ranges.pop_front();
             }
@@ -818,7 +832,7 @@ Columns MergeTreeRangeReader::continueReadingChain(ReadResult & result, size_t &
             num_rows += stream.finalize(columns);
             const auto & range = started_ranges[next_range_to_start].range;
             ++next_range_to_start;
-            stream = Stream(range.begin, range.end, merge_tree_reader);
+            stream = Stream(range.begin, range.end, 0, merge_tree_reader);
         }
 
         bool last = i + 1 == size;

src/Storages/MergeTree/MergeTreeRangeReader.h

@@ -62,7 +62,7 @@ public:
     {
     public:
         DelayedStream() = default;
-        DelayedStream(size_t from_mark, IMergeTreeReader * merge_tree_reader);
+        DelayedStream(size_t from_mark, size_t current_task_last_mark_, IMergeTreeReader * merge_tree_reader);
 
         /// Read @num_rows rows from @from_mark starting from @offset row
         /// Returns the number of rows added to block.
@@ -81,6 +81,8 @@ public:
         size_t current_offset = 0;
         /// Num of rows we have to read
         size_t num_delayed_rows = 0;
+        /// Last mark from all ranges of current task.
+        size_t current_task_last_mark = 0;
 
         /// Actual reader of data from disk
         IMergeTreeReader * merge_tree_reader = nullptr;
@@ -99,7 +101,8 @@ public:
     {
     public:
         Stream() = default;
-        Stream(size_t from_mark, size_t to_mark, IMergeTreeReader * merge_tree_reader);
+        Stream(size_t from_mark, size_t to_mark,
+               size_t current_task_last_mark, IMergeTreeReader * merge_tree_reader);
 
         /// Returns the number of rows added to block.
         size_t read(Columns & columns, size_t num_rows, bool skip_remaining_rows_in_current_granule);
@@ -122,6 +125,7 @@ public:
         /// Invariant: offset_after_current_mark + skipped_rows_after_offset < index_granularity
         size_t offset_after_current_mark = 0;
 
+        /// Last mark in current range.
         size_t last_mark = 0;
 
         IMergeTreeReader * merge_tree_reader = nullptr;

src/Storages/MergeTree/MergeTreeReaderCompact.cpp

@@ -121,7 +121,8 @@ MergeTreeReaderCompact::MergeTreeReaderCompact(
     }
 }
 
-size_t MergeTreeReaderCompact::readRows(size_t from_mark, bool continue_reading, size_t max_rows_to_read, Columns & res_columns)
+size_t MergeTreeReaderCompact::readRows(
+    size_t from_mark, size_t /* current_task_last_mark */, bool continue_reading, size_t max_rows_to_read, Columns & res_columns)
 {
     if (continue_reading)
         from_mark = next_mark;

src/Storages/MergeTree/MergeTreeReaderCompact.h

@@ -32,7 +32,8 @@ public:
 
     /// Return the number of rows has been read or zero if there is no columns to read.
     /// If continue_reading is true, continue reading from last state, otherwise seek to from_mark
-    size_t readRows(size_t from_mark, bool continue_reading, size_t max_rows_to_read, Columns & res_columns) override;
+    size_t readRows(size_t from_mark, size_t current_task_last_mark,
+                    bool continue_reading, size_t max_rows_to_read, Columns & res_columns) override;
 
     bool canReadIncompleteGranules() const override { return false; }
 

src/Storages/MergeTree/MergeTreeReaderInMemory.cpp

@@ -37,7 +37,8 @@ MergeTreeReaderInMemory::MergeTreeReaderInMemory(
     }
 }
 
-size_t MergeTreeReaderInMemory::readRows(size_t from_mark, bool continue_reading, size_t max_rows_to_read, Columns & res_columns)
+size_t MergeTreeReaderInMemory::readRows(
+    size_t from_mark, size_t /* current_task_last_mark */, bool continue_reading, size_t max_rows_to_read, Columns & res_columns)
 {
     if (!continue_reading)
         total_rows_read = 0;

src/Storages/MergeTree/MergeTreeReaderInMemory.h

@@ -23,7 +23,8 @@ public:
 
     /// Return the number of rows has been read or zero if there is no columns to read.
     /// If continue_reading is true, continue reading from last state, otherwise seek to from_mark
-    size_t readRows(size_t from_mark, bool continue_reading, size_t max_rows_to_read, Columns & res_columns) override;
+    size_t readRows(size_t from_mark, size_t current_tasl_last_mark,
+                    bool continue_reading, size_t max_rows_to_read, Columns & res_columns) override;
 
     bool canReadIncompleteGranules() const override { return true; }
 

src/Storages/MergeTree/MergeTreeReaderStream.cpp

@@ -1,6 +1,7 @@
 #include <Storages/MergeTree/MergeTreeReaderStream.h>
 #include <Compression/CachedCompressedReadBuffer.h>
 
+#include <base/getThreadId.h>
 #include <utility>
 
 
@@ -12,68 +13,38 @@ namespace ErrorCodes
     extern const int ARGUMENT_OUT_OF_BOUND;
 }
 
-
 MergeTreeReaderStream::MergeTreeReaderStream(
         DiskPtr disk_,
         const String & path_prefix_, const String & data_file_extension_, size_t marks_count_,
         const MarkRanges & all_mark_ranges,
         const MergeTreeReaderSettings & settings,
         MarkCache * mark_cache_,
-        UncompressedCache * uncompressed_cache, size_t file_size,
+        UncompressedCache * uncompressed_cache, size_t file_size_,
         const MergeTreeIndexGranularityInfo * index_granularity_info_,
         const ReadBufferFromFileBase::ProfileCallback & profile_callback, clockid_t clock_type)
-        : disk(std::move(disk_)), path_prefix(path_prefix_), data_file_extension(data_file_extension_), marks_count(marks_count_)
+    : disk(std::move(disk_))
-        , mark_cache(mark_cache_), save_marks_in_cache(settings.save_marks_in_cache)
+    , path_prefix(path_prefix_)
-        , index_granularity_info(index_granularity_info_)
+    , data_file_extension(data_file_extension_)
-        , marks_loader(disk, mark_cache, index_granularity_info->getMarksFilePath(path_prefix),
+    , marks_count(marks_count_)
-            marks_count, *index_granularity_info, save_marks_in_cache)
+    , file_size(file_size_)
+    , mark_cache(mark_cache_)
+    , save_marks_in_cache(settings.save_marks_in_cache)
+    , index_granularity_info(index_granularity_info_)
+    , marks_loader(disk, mark_cache, index_granularity_info->getMarksFilePath(path_prefix),
+        marks_count, *index_granularity_info, save_marks_in_cache)
 {
     /// Compute the size of the buffer.
     size_t max_mark_range_bytes = 0;
     size_t sum_mark_range_bytes = 0;
-    /// Rightmost bound to read.
-    size_t right_bound = 0;
 
     for (const auto & mark_range : all_mark_ranges)
     {
         size_t left_mark = mark_range.begin;
         size_t right_mark = mark_range.end;
-
+        auto [right_offset, mark_range_bytes] = getRightOffsetAndBytesRange(left_mark, right_mark);
-        /// NOTE: if we are reading the whole file, then right_mark == marks_count
-        /// and we will use max_read_buffer_size for buffer size, thus avoiding the need to load marks.
-
-        /// If the end of range is inside the block, we will need to read it too.
-        if (right_mark < marks_count && marks_loader.getMark(right_mark).offset_in_decompressed_block > 0)
-        {
-            auto indices = collections::range(right_mark, marks_count);
-            auto it = std::upper_bound(indices.begin(), indices.end(), right_mark, [this](size_t i, size_t j)
-            {
-                return marks_loader.getMark(i).offset_in_compressed_file < marks_loader.getMark(j).offset_in_compressed_file;
-            });
-
-            right_mark = (it == indices.end() ? marks_count : *it);
-        }
-
-        size_t mark_range_bytes;
-        size_t current_right_offset;
-
-        /// If there are no marks after the end of range, just use file size
-        if (right_mark >= marks_count
-            || (right_mark + 1 == marks_count
-                && marks_loader.getMark(right_mark).offset_in_compressed_file == marks_loader.getMark(mark_range.end).offset_in_compressed_file))
-        {
-            mark_range_bytes = file_size - (left_mark < marks_count ? marks_loader.getMark(left_mark).offset_in_compressed_file : 0);
-            current_right_offset = file_size;
-        }
-        else
-        {
-            mark_range_bytes = marks_loader.getMark(right_mark).offset_in_compressed_file - marks_loader.getMark(left_mark).offset_in_compressed_file;
-            current_right_offset = marks_loader.getMark(right_mark).offset_in_compressed_file;
-        }
 
         max_mark_range_bytes = std::max(max_mark_range_bytes, mark_range_bytes);
         sum_mark_range_bytes += mark_range_bytes;
-        right_bound = std::max(right_bound, current_right_offset);
     }
 
     /// Avoid empty buffer. May happen while reading dictionary for DataTypeLowCardinality.
@@ -82,9 +53,6 @@ MergeTreeReaderStream::MergeTreeReaderStream(
     if (max_mark_range_bytes != 0)
         read_settings = read_settings.adjustBufferSize(max_mark_range_bytes);
 
-    /// Set bound for reading from remote disk.
-    read_settings.remote_read_right_offset = right_bound;
-
     /// Initialize the objects that shall be used to perform read operations.
     if (uncompressed_cache)
     {
@@ -128,6 +96,45 @@ MergeTreeReaderStream::MergeTreeReaderStream(
 }
 
 
+std::pair<size_t, size_t> MergeTreeReaderStream::getRightOffsetAndBytesRange(size_t left_mark, size_t right_mark)
+{
+    /// NOTE: if we are reading the whole file, then right_mark == marks_count
+    /// and we will use max_read_buffer_size for buffer size, thus avoiding the need to load marks.
+
+    /// If the end of range is inside the block, we will need to read it too.
+    size_t result_right_mark = right_mark;
+    if (right_mark < marks_count && marks_loader.getMark(right_mark).offset_in_decompressed_block > 0)
+    {
+        auto indices = collections::range(right_mark, marks_count);
+        auto it = std::upper_bound(indices.begin(), indices.end(), right_mark, [this](size_t i, size_t j)
+        {
+            return marks_loader.getMark(i).offset_in_compressed_file < marks_loader.getMark(j).offset_in_compressed_file;
+        });
+
+        result_right_mark = (it == indices.end() ? marks_count : *it);
+    }
+
+    size_t right_offset;
+    size_t mark_range_bytes;
+
+    /// If there are no marks after the end of range, just use file size
+    if (result_right_mark >= marks_count
+        || (result_right_mark + 1 == marks_count
+            && marks_loader.getMark(result_right_mark).offset_in_compressed_file == marks_loader.getMark(right_mark).offset_in_compressed_file))
+    {
+        right_offset = file_size;
+        mark_range_bytes = right_offset - (left_mark < marks_count ? marks_loader.getMark(left_mark).offset_in_compressed_file : 0);
+    }
+    else
+    {
+        right_offset = marks_loader.getMark(result_right_mark).offset_in_compressed_file;
+        mark_range_bytes = right_offset - marks_loader.getMark(left_mark).offset_in_compressed_file;
+    }
+
+    return std::make_pair(right_offset, mark_range_bytes);
+}
+
+
 void MergeTreeReaderStream::seekToMark(size_t index)
 {
     MarkInCompressedFile mark = marks_loader.getMark(index);
@@ -172,4 +179,18 @@ void MergeTreeReaderStream::seekToStart()
     }
 }
 
+
+void MergeTreeReaderStream::adjustForRange(size_t left_mark, size_t right_mark)
+{
+    auto [right_offset, mark_range_bytes] = getRightOffsetAndBytesRange(left_mark, right_mark);
+    if (right_offset > last_right_offset)
+    {
+        last_right_offset = right_offset;
+        if (cached_buffer)
+            cached_buffer->setRightOffset(last_right_offset);
+        if (non_cached_buffer)
+            non_cached_buffer->setRightOffset(last_right_offset);
+    }
+}
+
 }

src/Storages/MergeTree/MergeTreeReaderStream.h

@@ -23,25 +23,32 @@ public:
         const MarkRanges & all_mark_ranges,
         const MergeTreeReaderSettings & settings_,
         MarkCache * mark_cache, UncompressedCache * uncompressed_cache,
-        size_t file_size, const MergeTreeIndexGranularityInfo * index_granularity_info_,
+        size_t file_size_, const MergeTreeIndexGranularityInfo * index_granularity_info_,
         const ReadBufferFromFileBase::ProfileCallback & profile_callback, clockid_t clock_type);
 
     void seekToMark(size_t index);
 
     void seekToStart();
 
+    void adjustForRange(size_t left_mark, size_t right_mark);
+
     ReadBuffer * data_buffer;
 
 private:
+    std::pair<size_t, size_t> getRightOffsetAndBytesRange(size_t left_mark, size_t right_mark);
+
     DiskPtr disk;
     std::string path_prefix;
     std::string data_file_extension;
 
     size_t marks_count;
+    size_t file_size;
 
     MarkCache * mark_cache;
     bool save_marks_in_cache;
 
+    size_t last_right_offset = 0;
+
     const MergeTreeIndexGranularityInfo * index_granularity_info;
 
     std::unique_ptr<CachedCompressedReadBuffer> cached_buffer;

src/Storages/MergeTree/MergeTreeReaderWide.cpp

@@ -61,7 +61,8 @@ MergeTreeReaderWide::MergeTreeReaderWide(
 }
 
 
-size_t MergeTreeReaderWide::readRows(size_t from_mark, bool continue_reading, size_t max_rows_to_read, Columns & res_columns)
+size_t MergeTreeReaderWide::readRows(
+    size_t from_mark, size_t current_task_last_mark, bool continue_reading, size_t max_rows_to_read, Columns & res_columns)
 {
     size_t read_rows = 0;
     try
@@ -87,7 +88,7 @@ size_t MergeTreeReaderWide::readRows(size_t from_mark, bool continue_reading, si
                 try
                 {
                     auto & cache = caches[column_from_part.getNameInStorage()];
-                    prefetch(column_from_part, from_mark, continue_reading, cache, prefetched_streams);
+                    prefetch(column_from_part, from_mark, continue_reading, current_task_last_mark, cache, prefetched_streams);
                 }
                 catch (Exception & e)
                 {
@@ -117,7 +118,7 @@ size_t MergeTreeReaderWide::readRows(size_t from_mark, bool continue_reading, si
                 auto & cache = caches[column_from_part.getNameInStorage()];
 
                 readData(
-                    column_from_part, column, from_mark, continue_reading,
+                    column_from_part, column, from_mark, continue_reading, current_task_last_mark,
                     max_rows_to_read, cache, /* was_prefetched =*/ !prefetched_streams.empty());
 
                 /// For elements of Nested, column_size_before_reading may be greater than column size
@@ -199,6 +200,7 @@ static ReadBuffer * getStream(
     MergeTreeReaderWide::FileStreams & streams,
     const NameAndTypePair & name_and_type,
     size_t from_mark, bool seek_to_mark,
+    size_t current_task_last_mark,
     ISerialization::SubstreamsCache & cache)
 {
     /// If substream have already been read.
@@ -212,6 +214,7 @@ static ReadBuffer * getStream(
         return nullptr;
 
     MergeTreeReaderStream & stream = *it->second;
+    stream.adjustForRange(seek_to_start ? 0 : from_mark, current_task_last_mark);
 
     if (seek_to_start)
         stream.seekToStart();
@@ -226,6 +229,7 @@ void MergeTreeReaderWide::prefetch(
     const NameAndTypePair & name_and_type,
     size_t from_mark,
     bool continue_reading,
+    size_t current_task_last_mark,
     ISerialization::SubstreamsCache & cache,
     std::unordered_set<std::string> & prefetched_streams)
 {
@@ -239,7 +243,7 @@ void MergeTreeReaderWide::prefetch(
         if (!prefetched_streams.count(stream_name))
         {
             bool seek_to_mark = !continue_reading;
-            if (ReadBuffer * buf = getStream(false, substream_path, streams, name_and_type, from_mark, seek_to_mark, cache))
+            if (ReadBuffer * buf = getStream(false, substream_path, streams, name_and_type, from_mark, seek_to_mark, current_task_last_mark, cache))
                 buf->prefetch();
 
             prefetched_streams.insert(stream_name);
@@ -250,8 +254,8 @@ void MergeTreeReaderWide::prefetch(
 
 void MergeTreeReaderWide::readData(
     const NameAndTypePair & name_and_type, ColumnPtr & column,
-    size_t from_mark, bool continue_reading, size_t max_rows_to_read,
+    size_t from_mark, bool continue_reading, size_t current_task_last_mark,
-    ISerialization::SubstreamsCache & cache, bool was_prefetched)
+    size_t max_rows_to_read, ISerialization::SubstreamsCache & cache, bool was_prefetched)
 {
     double & avg_value_size_hint = avg_value_size_hints[name_and_type.name];
     ISerialization::DeserializeBinaryBulkSettings deserialize_settings;
@@ -264,7 +268,7 @@ void MergeTreeReaderWide::readData(
     {
         deserialize_settings.getter = [&](const ISerialization::SubstreamPath & substream_path)
         {
-            return getStream(/* seek_to_start = */true, substream_path, streams, name_and_type, from_mark, /* seek_to_mark = */false, cache);
+            return getStream(/* seek_to_start = */true, substream_path, streams, name_and_type, from_mark, /* seek_to_mark = */false, current_task_last_mark, cache);
         };
         serialization->deserializeBinaryBulkStatePrefix(deserialize_settings, deserialize_binary_bulk_state_map[name]);
     }
@@ -275,7 +279,7 @@ void MergeTreeReaderWide::readData(
 
         return getStream(
             /* seek_to_start = */false, substream_path, streams, name_and_type, from_mark,
-            seek_to_mark, cache);
+            seek_to_mark, current_task_last_mark, cache);
     };
     deserialize_settings.continuous_reading = continue_reading;
     auto & deserialize_state = deserialize_binary_bulk_state_map[name];

src/Storages/MergeTree/MergeTreeReaderWide.h

@@ -28,7 +28,8 @@ public:
 
     /// Return the number of rows has been read or zero if there is no columns to read.
     /// If continue_reading is true, continue reading from last state, otherwise seek to from_mark
-    size_t readRows(size_t from_mark, bool continue_reading, size_t max_rows_to_read, Columns & res_columns) override;
+    size_t readRows(size_t from_mark, size_t current_task_last_mark,
+                    bool continue_reading, size_t max_rows_to_read, Columns & res_columns) override;
 
     bool canReadIncompleteGranules() const override { return true; }
 
@@ -39,13 +40,14 @@ private:
     FileStreams streams;
     Serializations serializations;
     DiskPtr disk;
+    std::map<String, std::set<size_t>> marks;
 
     void addStreams(const NameAndTypePair & name_and_type,
         const ReadBufferFromFileBase::ProfileCallback & profile_callback, clockid_t clock_type);
 
     void readData(
         const NameAndTypePair & name_and_type, ColumnPtr & column,
-        size_t from_mark, bool continue_reading, size_t max_rows_to_read,
+        size_t from_mark, bool continue_reading, size_t current_task_last_mark, size_t max_rows_to_read,
         ISerialization::SubstreamsCache & cache, bool was_prefetched);
 
     /// Make next readData more simple by calling 'prefetch' of all related ReadBuffers (column streams).
@@ -53,6 +55,7 @@ private:
         const NameAndTypePair & name_and_type,
         size_t from_mark,
         bool continue_reading,
+        size_t current_task_last_mark,
         ISerialization::SubstreamsCache & cache,
         std::unordered_set<std::string> & prefetched_streams); /// if stream was already prefetched do nothing
 };

src/Storages/MergeTree/MergeTreeSequentialSource.cpp

@@ -78,7 +78,8 @@ try
 
         const auto & sample = reader->getColumns();
         Columns columns(sample.size());
-        size_t rows_read = reader->readRows(current_mark, continue_reading, rows_to_read, columns);
+        /// TODO: pass stream size instead of zero?
+        size_t rows_read = reader->readRows(current_mark, 0, continue_reading, rows_to_read, columns);
 
         if (rows_read)
         {