ClickHouse/dbms/src/Storages/MergeTree/ShardedPartitionUploader.cpp

#include <Storages/MergeTree/ShardedPartitionUploader.h>
#include <Storages/MergeTree/ReplicatedMergeTreeAddress.h>
#include <Storages/StorageReplicatedMergeTree.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteHelpers.h>
#include <IO/InterserverWriteBuffer.h>
#include <Poco/File.h>


namespace CurrentMetrics
{
    extern const Metric ReplicatedSend;
    extern const Metric ReplicatedFetch;
}

namespace DB
{

namespace ErrorCodes
{
    extern const int ABORTED;
    extern const int BAD_SIZE_OF_FILE_IN_DATA_PART;
}

namespace ShardedPartitionUploader
{

namespace
{

std::string getEndpointId(const std::string & node_id)
{
    return "ShardedPartitionUploader:" + node_id;
}

}

Service::Service(StoragePtr & storage_)
    : owned_storage{storage_}, data{static_cast<StorageReplicatedMergeTree &>(*storage_).getData()}
{
}

std::string Service::getId(const std::string & node_id) const
{
    return getEndpointId(node_id);
}

void Service::processQuery(const Poco::Net::HTMLForm & params, ReadBuffer & body, WriteBuffer & out, Poco::Net::HTTPServerResponse & response)
{
    std::string part_name = params.get("path");
    std::string replica_path = params.get("endpoint");

    static const String TMP_PREFIX = "tmp_resharded_fetch_";
    String relative_part_name = String("detached/") + TMP_PREFIX + part_name;
    String absolute_part_path = data.getFullPath() + relative_part_name + "/";
    Poco::File part_file{absolute_part_path};

    if (part_file.exists())
    {
        LOG_ERROR(log, "Directory " + absolute_part_path + " already exists. Removing.");
        part_file.remove(true);
    }

    CurrentMetrics::Increment metric_increment{CurrentMetrics::ReplicatedFetch};

    part_file.createDirectory();

    MergeTreeData::MutableDataPartPtr data_part = std::make_shared<MergeTreeData::DataPart>(data);
    data_part->name = part_name;
    data_part->relative_path = relative_part_name;
    data_part->is_temp = true;

    size_t files;
    readBinary(files, body);
    MergeTreeData::DataPart::Checksums checksums;
    for (size_t i = 0; i < files; ++i)
    {
        String file_name;
        UInt64 file_size;

        readStringBinary(file_name, body);
        readBinary(file_size, body);

        WriteBufferFromFile file_out{absolute_part_path + file_name};
        HashingWriteBuffer hashing_out{file_out};
        copyData(body, hashing_out, file_size, is_cancelled);

        if (is_cancelled)
        {
            part_file.remove(true);
            throw Exception{"Fetching of part was cancelled", ErrorCodes::ABORTED};
        }

        MergeTreeDataPartChecksum::uint128 expected_hash;
        readPODBinary(expected_hash, body);

        if (expected_hash != hashing_out.getHash())
            throw Exception{"Checksum mismatch for file " + absolute_part_path + file_name + " transferred from " + replica_path};

        if (file_name != "checksums.txt" &&
            file_name != "columns.txt")
            checksums.addFile(file_name, file_size, expected_hash);
    }

    assertEOF(body);

    ActiveDataPartSet::parsePartName(part_name, *data_part);
    data_part->modification_time = time(0);
    data_part->loadColumns(true);
    data_part->loadChecksums(true);
    data_part->loadIndex();
    data_part->is_sharded = false;
    data_part->checksums.checkEqual(checksums, false);

    /// Now store permanently the received part.
    /// NOTE: will remove dst dir if it exists
    data_part->renameTo("detached/" + part_name, true);
    data_part->is_temp = false;
}

Client::Client(StorageReplicatedMergeTree & storage_)
    : storage{storage_}, data{storage_.getData()}
{
}

MergeTreeData::DataPartPtr Client::findShardedPart(const String & name, size_t shard_no)
{
    MergeTreeData::DataPartPtr part = data.getShardedPartIfExists(name, shard_no);
    if (part)
        return part;
    throw Exception("No part " + name + " in table");
}

void Client::setCancellationHook(CancellationHook cancellation_hook_)
{
    cancellation_hook = cancellation_hook_;
}

bool Client::send(const std::string & part_name, size_t shard_no,
    const InterserverIOEndpointLocation & to_location)
{
    std::function<void()> copy_hook = std::bind(&ShardedPartitionUploader::Client::abortIfRequested, this);

    abortIfRequested();

    InterserverWriteBuffer out{to_location.host, to_location.port, getEndpointId(to_location.name), part_name};

    LOG_TRACE(log, "Sending part " << part_name);

    auto storage_lock = storage.lockStructure(false);

    MergeTreeData::DataPartPtr part = findShardedPart(part_name, shard_no);

    Poco::ScopedReadRWLock part_lock{part->columns_lock};

    CurrentMetrics::Increment metric_increment{CurrentMetrics::ReplicatedSend};

    /// We take a list of files from list of checksums.
    MergeTreeData::DataPart::Checksums checksums = part->checksums;
    /// Add files that are not in checksum list.
    checksums.files["checksums.txt"];
    checksums.files["columns.txt"];

    MergeTreeData::DataPart::Checksums data_checksums;

    writeBinary(checksums.files.size(), out);
    for (const auto & it : checksums.files)
    {
        String file_name = it.first;
        String path = data.getFullPath() + "reshard/" + toString(shard_no) + "/" + part_name + "/" + file_name;
        UInt64 size = Poco::File(path).getSize();

        writeStringBinary(it.first, out);
        writeBinary(size, out);

        ReadBufferFromFile file_in{path};
        HashingWriteBuffer hashing_out{out};
        copyData(file_in, hashing_out, copy_hook);

        abortIfRequested();

        if (hashing_out.count() != size)
            throw Exception{"Unexpected size of file " + path, ErrorCodes::BAD_SIZE_OF_FILE_IN_DATA_PART};

        writePODBinary(hashing_out.getHash(), out);

        if (file_name != "checksums.txt" &&
            file_name != "columns.txt")
            data_checksums.addFile(file_name, hashing_out.count(), hashing_out.getHash());
    }

    part->checksums.checkEqual(data_checksums, false);

    return true;
}

void Client::abortIfRequested()
{
    if (is_cancelled)
        throw Exception{"ShardedPartitionUploader service terminated", ErrorCodes::ABORTED};

    if (cancellation_hook)
        cancellation_hook();
}

}

}