ClickHouse/src/Storages/MergeTree/MutatePlainMergeTreeTask.cpp

#include <Storages/MergeTree/MutatePlainMergeTreeTask.h>

#include <Storages/StorageMergeTree.h>
#include <Interpreters/TransactionLog.h>
#include <Common/ProfileEventsScope.h>

namespace DB
{

namespace ErrorCodes
{
    extern const int LOGICAL_ERROR;
}


StorageID MutatePlainMergeTreeTask::getStorageID() const
{
    return storage.getStorageID();
}

void MutatePlainMergeTreeTask::onCompleted()
{
    bool delay = state == State::SUCCESS;
    task_result_callback(delay);
}

void MutatePlainMergeTreeTask::prepare()
{
    future_part = merge_mutate_entry->future_part;

    task_context = createTaskContext();
    merge_list_entry = storage.getContext()->getMergeList().insert(
        storage.getStorageID(),
        future_part,
        task_context);

    stopwatch = std::make_unique<Stopwatch>();

    write_part_log = [this] (const ExecutionStatus & execution_status)
    {
        auto profile_counters_snapshot = std::make_shared<ProfileEvents::Counters::Snapshot>(profile_counters.getPartiallyAtomicSnapshot());
        mutate_task.reset();
        storage.writePartLog(
            PartLogElement::MUTATE_PART,
            execution_status,
            stopwatch->elapsed(),
            future_part->name,
            new_part,
            future_part->parts,
            merge_list_entry.get(),
            std::move(profile_counters_snapshot));
    };

    if (task_context->getSettingsRef().enable_sharing_sets_for_mutations)
    {
        /// If we have a prepared sets cache for this mutations, we will use it.
        auto mutation_id = future_part->part_info.mutation;
        auto prepared_sets_cache_for_mutation = storage.getPreparedSetsCache(mutation_id);
        task_context->setPreparedSetsCache(prepared_sets_cache_for_mutation);
    }

    mutate_task = storage.merger_mutator.mutatePartToTemporaryPart(
            future_part, metadata_snapshot, merge_mutate_entry->commands, merge_list_entry.get(),
            time(nullptr), task_context, merge_mutate_entry->txn, merge_mutate_entry->tagger->reserved_space, table_lock_holder);
}


bool MutatePlainMergeTreeTask::executeStep()
{
    /// Metrics will be saved in the local profile_counters.
    ProfileEventsScope profile_events_scope(&profile_counters);

    /// Make out memory tracker a parent of current thread memory tracker
    std::optional<ThreadGroupSwitcher> switcher;
    if (merge_list_entry)
        switcher.emplace((*merge_list_entry)->thread_group);

    switch (state)
    {
        case State::NEED_PREPARE:
        {
            prepare();
            state = State::NEED_EXECUTE;
            return true;
        }
        case State::NEED_EXECUTE:
        {
            try
            {
                if (mutate_task->execute())
                    return true;

                new_part = mutate_task->getFuture().get();
                auto & data_part_storage = new_part->getDataPartStorage();
                if (data_part_storage.hasActiveTransaction())
                    data_part_storage.precommitTransaction();

                MergeTreeData::Transaction transaction(storage, merge_mutate_entry->txn.get());
                /// FIXME Transactions: it's too optimistic, better to lock parts before starting transaction
                storage.renameTempPartAndReplace(new_part, transaction);
                transaction.commit();

                storage.updateMutationEntriesErrors(future_part, true, "");
                write_part_log({});

                state = State::NEED_FINISH;
                return true;
            }
            catch (...)
            {
                if (merge_mutate_entry->txn)
                    merge_mutate_entry->txn->onException();
                PreformattedMessage exception_message = getCurrentExceptionMessageAndPattern(/* with_stacktrace */ false);
                LOG_ERROR(&Poco::Logger::get("MutatePlainMergeTreeTask"), exception_message);
                storage.updateMutationEntriesErrors(future_part, false, exception_message.text);
                write_part_log(ExecutionStatus::fromCurrentException("", true));
                tryLogCurrentException(__PRETTY_FUNCTION__);
                return false;
            }
        }
        case State::NEED_FINISH:
        {
            // Nothing to do
            state = State::SUCCESS;
            return false;
        }
        case State::SUCCESS:
        {
            throw Exception(ErrorCodes::LOGICAL_ERROR, "Task with state SUCCESS mustn't be executed again");
        }
    }

    return false;
}

ContextMutablePtr MutatePlainMergeTreeTask::createTaskContext() const
{
    auto context = Context::createCopy(storage.getContext());
    context->makeQueryContext();
    auto queryId = getQueryId();
    context->setCurrentQueryId(queryId);
    return context;
}

}