executeQuery.cpp

#include <Common/formatReadable.h>
#include <Common/PODArray.h>
#include <Common/typeid_cast.h>

#include <IO/ConcatReadBuffer.h>
#include <IO/WriteBufferFromFile.h>
#include <IO/WriteBufferFromVector.h>
#include <IO/LimitReadBuffer.h>
#include <IO/copyData.h>

#include <DataStreams/BlockIO.h>
#include <DataStreams/copyData.h>
#include <DataStreams/IBlockInputStream.h>
#include <DataStreams/InputStreamFromASTInsertQuery.h>
#include <DataStreams/CountingBlockOutputStream.h>

#include <Parsers/ASTInsertQuery.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTShowProcesslistQuery.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ParserQuery.h>
#include <Parsers/parseQuery.h>
#include <Parsers/queryToString.h>
#include <Parsers/ASTWatchQuery.h>
#include <Parsers/Lexer.h>

#include <Storages/StorageInput.h>

#include <Access/EnabledQuota.h>
#include <Interpreters/InterpreterFactory.h>
#include <Interpreters/ProcessList.h>
#include <Interpreters/OpenTelemetryLog.h>
#include <Interpreters/QueryLog.h>
#include <Interpreters/InterpreterSetQuery.h>
#include <Interpreters/ReplaceQueryParameterVisitor.h>
#include <Interpreters/executeQuery.h>
#include <Interpreters/Context.h>
#include <Common/ProfileEvents.h>

#include <Interpreters/DNSCacheUpdater.h>
#include <Common/SensitiveDataMasker.h>

#include <Processors/Transforms/LimitsCheckingTransform.h>
#include <Processors/Transforms/MaterializingTransform.h>
#include <Processors/Formats/IOutputFormat.h>


namespace ProfileEvents
{
    extern const Event QueryMaskingRulesMatch;
    extern const Event FailedQuery;
    extern const Event FailedInsertQuery;
    extern const Event FailedSelectQuery;
    extern const Event QueryTimeMicroseconds;
    extern const Event SelectQueryTimeMicroseconds;
    extern const Event InsertQueryTimeMicroseconds;
}

namespace DB
{

namespace ErrorCodes
{
    extern const int INTO_OUTFILE_NOT_ALLOWED;
    extern const int QUERY_WAS_CANCELLED;
}


static void checkASTSizeLimits(const IAST & ast, const Settings & settings)
{
    if (settings.max_ast_depth)
        ast.checkDepth(settings.max_ast_depth);
    if (settings.max_ast_elements)
        ast.checkSize(settings.max_ast_elements);
}


static String joinLines(const String & query)
{
    /// Care should be taken. We don't join lines inside non-whitespace tokens (e.g. multiline string literals)
    ///  and we don't join line after comment (because it can be single-line comment).
    /// All other whitespaces replaced to a single whitespace.

    String res;
    const char * begin = query.data();
    const char * end = begin + query.size();

    Lexer lexer(begin, end);
    Token token = lexer.nextToken();
    for (; !token.isEnd(); token = lexer.nextToken())
    {
        if (token.type == TokenType::Whitespace)
        {
            res += ' ';
        }
        else if (token.type == TokenType::Comment)
        {
            res.append(token.begin, token.end);
            if (token.end < end && *token.end == '\n')
                res += '\n';
        }
        else
            res.append(token.begin, token.end);
    }

    return res;
}


static String prepareQueryForLogging(const String & query, Context & context)
{
    String res = query;

    // wiping sensitive data before cropping query by log_queries_cut_to_length,
    // otherwise something like credit card without last digit can go to log
    if (auto * masker = SensitiveDataMasker::getInstance())
    {
        auto matches = masker->wipeSensitiveData(res);
        if (matches > 0)
        {
            ProfileEvents::increment(ProfileEvents::QueryMaskingRulesMatch, matches);
        }
    }

    res = res.substr(0, context.getSettingsRef().log_queries_cut_to_length);

    return res;
}


/// Log query into text log (not into system table).
static void logQuery(const String & query, const Context & context, bool internal)
{
    if (internal)
    {
        LOG_DEBUG(&Poco::Logger::get("executeQuery"), "(internal) {}", joinLines(query));
    }
    else
    {
        const auto & current_query_id = context.getClientInfo().current_query_id;
        const auto & initial_query_id = context.getClientInfo().initial_query_id;
        const auto & current_user = context.getClientInfo().current_user;

        LOG_DEBUG(&Poco::Logger::get("executeQuery"), "(from {}{}{}) {}",
            context.getClientInfo().current_address.toString(),
            (current_user != "default" ? ", user: " + context.getClientInfo().current_user : ""),
            (!initial_query_id.empty() && current_query_id != initial_query_id ? ", initial_query_id: " + initial_query_id : std::string()),
            joinLines(query));
        
        LOG_TRACE(&Poco::Logger::get("executeQuery"),
            "OpenTelemetry trace id {:x}, span id {:x}, parent span id {:x}",
            context.getClientInfo().trace_id, context.getClientInfo().span_id,
            context.getClientInfo().parent_span_id);
    }
}


/// Call this inside catch block.
static void setExceptionStackTrace(QueryLogElement & elem)
{
    /// Disable memory tracker for stack trace.
    /// Because if exception is "Memory limit (for query) exceed", then we probably can't allocate another one string.
    auto temporarily_disable_memory_tracker = getCurrentMemoryTrackerActionLock();

    try
    {
        throw;
    }
    catch (const std::exception & e)
    {
        elem.stack_trace = getExceptionStackTraceString(e);
    }
    catch (...) {}
}


/// Log exception (with query info) into text log (not into system table).
static void logException(Context & context, QueryLogElement & elem)
{
    if (elem.stack_trace.empty())
        LOG_ERROR(&Poco::Logger::get("executeQuery"), "{} (from {}) (in query: {})",
            elem.exception, context.getClientInfo().current_address.toString(), joinLines(elem.query));
    else
        LOG_ERROR(&Poco::Logger::get("executeQuery"), "{} (from {}) (in query: {})"
            ", Stack trace (when copying this message, always include the lines below):\n\n{}",
            elem.exception, context.getClientInfo().current_address.toString(), joinLines(elem.query), elem.stack_trace);
}


static void onExceptionBeforeStart(const String & query_for_logging, Context & context, time_t current_time, ASTPtr ast)
{
    /// Exception before the query execution.
    if (auto quota = context.getQuota())
        quota->used(Quota::ERRORS, 1, /* check_exceeded = */ false);

    const Settings & settings = context.getSettingsRef();

    /// Log the start of query execution into the table if necessary.
    QueryLogElement elem;

    elem.type = QueryLogElementType::EXCEPTION_BEFORE_START;

    elem.event_time = current_time;
    elem.query_start_time = current_time;

    elem.current_database = context.getCurrentDatabase();
    elem.query = query_for_logging;
    elem.exception_code = getCurrentExceptionCode();
    elem.exception = getCurrentExceptionMessage(false);

    elem.client_info = context.getClientInfo();

    if (settings.calculate_text_stack_trace)
        setExceptionStackTrace(elem);
    logException(context, elem);

    /// Update performance counters before logging to query_log
    CurrentThread::finalizePerformanceCounters();

    if (settings.log_queries && elem.type >= settings.log_queries_min_type)
        if (auto query_log = context.getQueryLog())
            query_log->add(elem);

    if (auto opentelemetry_log = context.getOpenTelemetryLog())
    {
        OpenTelemetrySpanLogElement span;
        span.trace_id = context.getClientInfo().trace_id;
        span.span_id = context.getClientInfo().span_id;
        span.parent_span_id = context.getClientInfo().parent_span_id;
        span.operation_name = "query";
        span.start_time = current_time;
        span.finish_time = current_time;

        // keep values synchonized to type enum in QueryLogElement::createBlock
        span.attribute_names.push_back("status");
        span.attribute_values.push_back("ExceptionBeforeStart");

        span.attribute_names.push_back("query");
        span.attribute_values.push_back(elem.query);

        span.attribute_names.push_back("query_id");
        span.attribute_values.push_back(elem.client_info.current_query_id);

        opentelemetry_log->add(span);
    }

    ProfileEvents::increment(ProfileEvents::FailedQuery);

    if (ast)
    {
        if (ast->as<ASTSelectQuery>() || ast->as<ASTSelectWithUnionQuery>())
        {
            ProfileEvents::increment(ProfileEvents::FailedSelectQuery);
        }
        else if (ast->as<ASTInsertQuery>())
        {
            ProfileEvents::increment(ProfileEvents::FailedInsertQuery);
        }
    }
}

static void setQuerySpecificSettings(ASTPtr & ast, Context & context)
{
    if (auto * ast_insert_into = dynamic_cast<ASTInsertQuery *>(ast.get()))
    {
        if (ast_insert_into->watch)
            context.setSetting("output_format_enable_streaming", 1);
    }
}

static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
    const char * begin,
    const char * end,
    Context & context,
    bool internal,
    QueryProcessingStage::Enum stage,
    bool has_query_tail,
    ReadBuffer * istr)
{
    time_t current_time = time(nullptr);

    /// If we already executing query and it requires to execute internal query, than
    /// don't replace thread context with given (it can be temporary). Otherwise, attach context to thread.
    if (!internal)
    {
        context.makeQueryContext();
        CurrentThread::attachQueryContext(context);
    }

    const Settings & settings = context.getSettingsRef();

    ParserQuery parser(end, settings.enable_debug_queries);
    ASTPtr ast;
    const char * query_end;

    /// Don't limit the size of internal queries.
    size_t max_query_size = 0;
    if (!internal)
        max_query_size = settings.max_query_size;

    try
    {
        /// TODO Parser should fail early when max_query_size limit is reached.
        ast = parseQuery(parser, begin, end, "", max_query_size, settings.max_parser_depth);

        auto * insert_query = ast->as<ASTInsertQuery>();

        if (insert_query && insert_query->settings_ast)
            InterpreterSetQuery(insert_query->settings_ast, context).executeForCurrentContext();

        if (insert_query && insert_query->data)
        {
            query_end = insert_query->data;
            insert_query->has_tail = has_query_tail;
        }
        else
        {
            query_end = end;
        }
    }
    catch (...)
    {
        /// Anyway log the query.
        String query = String(begin, begin + std::min(end - begin, static_cast<ptrdiff_t>(max_query_size)));

        auto query_for_logging = prepareQueryForLogging(query, context);
        logQuery(query_for_logging, context, internal);

        if (!internal)
            onExceptionBeforeStart(query_for_logging, context, current_time, ast);

        throw;
    }

    setQuerySpecificSettings(ast, context);

    /// Copy query into string. It will be written to log and presented in processlist. If an INSERT query, string will not include data to insertion.
    String query(begin, query_end);
    BlockIO res;

    String query_for_logging;

    try
    {
        /// Replace ASTQueryParameter with ASTLiteral for prepared statements.
        if (context.hasQueryParameters())
        {
            ReplaceQueryParameterVisitor visitor(context.getQueryParameters());
            visitor.visit(ast);

            /// Get new query after substitutions.
            query = serializeAST(*ast);
        }

        query_for_logging = prepareQueryForLogging(query, context);

        logQuery(query_for_logging, context, internal);

        /// Check the limits.
        checkASTSizeLimits(*ast, settings);

        /// Put query to process list. But don't put SHOW PROCESSLIST query itself.
        ProcessList::EntryPtr process_list_entry;
        if (!internal && !ast->as<ASTShowProcesslistQuery>())
        {
            /// processlist also has query masked now, to avoid secrets leaks though SHOW PROCESSLIST by other users.
            process_list_entry = context.getProcessList().insert(query_for_logging, ast.get(), context);
            context.setProcessListElement(&process_list_entry->get());
        }

        /// Load external tables if they were provided
        context.initializeExternalTablesIfSet();

        auto * insert_query = ast->as<ASTInsertQuery>();
        if (insert_query && insert_query->select)
        {
            /// Prepare Input storage before executing interpreter if we already got a buffer with data.
            if (istr)
            {
                ASTPtr input_function;
                insert_query->tryFindInputFunction(input_function);
                if (input_function)
                {
                    StoragePtr storage = context.executeTableFunction(input_function);
                    auto & input_storage = dynamic_cast<StorageInput &>(*storage);
                    auto input_metadata_snapshot = input_storage.getInMemoryMetadataPtr();
                    BlockInputStreamPtr input_stream = std::make_shared<InputStreamFromASTInsertQuery>(
                        ast, istr, input_metadata_snapshot->getSampleBlock(), context, input_function);
                    input_storage.setInputStream(input_stream);
                }
            }
        }
        else
            /// reset Input callbacks if query is not INSERT SELECT
            context.resetInputCallbacks();

        auto interpreter = InterpreterFactory::get(ast, context, stage);

        std::shared_ptr<const EnabledQuota> quota;
        if (!interpreter->ignoreQuota())
        {
            quota = context.getQuota();
            if (quota)
            {
                quota->used(Quota::QUERIES, 1);
                quota->checkExceeded(Quota::ERRORS);
            }
        }

        IBlockInputStream::LocalLimits limits;
        if (!interpreter->ignoreLimits())
        {
            limits.mode = IBlockInputStream::LIMITS_CURRENT;
            limits.size_limits = SizeLimits(settings.max_result_rows, settings.max_result_bytes, settings.result_overflow_mode);
        }

        res = interpreter->execute();
        QueryPipeline & pipeline = res.pipeline;
        bool use_processors = pipeline.initialized();

        if (res.pipeline.initialized())
            use_processors = true;

        if (const auto * insert_interpreter = typeid_cast<const InterpreterInsertQuery *>(&*interpreter))
        {
            /// Save insertion table (not table function). TODO: support remote() table function.
            auto table_id = insert_interpreter->getDatabaseTable();
            if (!table_id.empty())
                context.setInsertionTable(std::move(table_id));
        }

        if (process_list_entry)
        {
            /// Query was killed before execution
            if ((*process_list_entry)->isKilled())
                throw Exception("Query '" + (*process_list_entry)->getInfo().client_info.current_query_id + "' is killed in pending state",
                    ErrorCodes::QUERY_WAS_CANCELLED);
            else if (!use_processors)
                (*process_list_entry)->setQueryStreams(res);
        }

        /// Hold element of process list till end of query execution.
        res.process_list_entry = process_list_entry;

        if (use_processors)
        {
            /// Limits on the result, the quota on the result, and also callback for progress.
            /// Limits apply only to the final result.
            pipeline.setProgressCallback(context.getProgressCallback());
            pipeline.setProcessListElement(context.getProcessListElement());
            if (stage == QueryProcessingStage::Complete && !pipeline.isCompleted())
            {
                pipeline.resize(1);
                pipeline.addSimpleTransform([&](const Block & header)
                {
                    auto transform = std::make_shared<LimitsCheckingTransform>(header, limits);
                    transform->setQuota(quota);
                    return transform;
                });
            }
        }
        else
        {
            /// Limits on the result, the quota on the result, and also callback for progress.
            /// Limits apply only to the final result.
            if (res.in)
            {
                res.in->setProgressCallback(context.getProgressCallback());
                res.in->setProcessListElement(context.getProcessListElement());
                if (stage == QueryProcessingStage::Complete)
                {
                    if (!interpreter->ignoreQuota())
                        res.in->setQuota(quota);
                    if (!interpreter->ignoreLimits())
                        res.in->setLimits(limits);
                }
            }

            if (res.out)
            {
                if (auto * stream = dynamic_cast<CountingBlockOutputStream *>(res.out.get()))
                {
                    stream->setProcessListElement(context.getProcessListElement());
                }
            }
        }

        /// Everything related to query log.
        {
            QueryLogElement elem;

            elem.type = QueryLogElementType::QUERY_START;

            elem.event_time = current_time;
            elem.query_start_time = current_time;

            elem.current_database = context.getCurrentDatabase();
            elem.query = query_for_logging;

            elem.client_info = context.getClientInfo();

            bool log_queries = settings.log_queries && !internal;

            /// Log into system table start of query execution, if need.
            if (log_queries)
            {
                if (settings.log_query_settings)
                    elem.query_settings = std::make_shared<Settings>(context.getSettingsRef());

                if (elem.type >= settings.log_queries_min_type)
                {
                    if (auto query_log = context.getQueryLog())
                        query_log->add(elem);
                }
            }

            /// Common code for finish and exception callbacks
            auto status_info_to_query_log = [](QueryLogElement &element, const QueryStatusInfo &info, const ASTPtr query_ast) mutable
            {
                DB::UInt64 query_time = info.elapsed_seconds * 1000000;
                ProfileEvents::increment(ProfileEvents::QueryTimeMicroseconds, query_time);
                if (query_ast->as<ASTSelectQuery>() || query_ast->as<ASTSelectWithUnionQuery>())
                {
                    ProfileEvents::increment(ProfileEvents::SelectQueryTimeMicroseconds, query_time);
                }
                else if (query_ast->as<ASTInsertQuery>())
                {
                    ProfileEvents::increment(ProfileEvents::InsertQueryTimeMicroseconds, query_time);
                }

                element.query_duration_ms = info.elapsed_seconds * 1000;

                element.read_rows = info.read_rows;
                element.read_bytes = info.read_bytes;

                element.written_rows = info.written_rows;
                element.written_bytes = info.written_bytes;

                element.memory_usage = info.peak_memory_usage > 0 ? info.peak_memory_usage : 0;

                element.thread_ids = std::move(info.thread_ids);
                element.profile_counters = std::move(info.profile_counters);
            };

            /// Also make possible for caller to log successful query finish and exception during execution.
            auto finish_callback = [elem, &context, ast, log_queries, log_queries_min_type = settings.log_queries_min_type,
                status_info_to_query_log]
                (IBlockInputStream * stream_in, IBlockOutputStream * stream_out, QueryPipeline * query_pipeline) mutable
            {
                QueryStatus * process_list_elem = context.getProcessListElement();

                if (!process_list_elem)
                    return;

                /// Update performance counters before logging to query_log
                CurrentThread::finalizePerformanceCounters();

                QueryStatusInfo info = process_list_elem->getInfo(true, context.getSettingsRef().log_profile_events);

                double elapsed_seconds = info.elapsed_seconds;

                elem.type = QueryLogElementType::QUERY_FINISH;

                elem.event_time = time(nullptr);

                status_info_to_query_log(elem, info, ast);

                auto progress_callback = context.getProgressCallback();

                if (progress_callback)
                    progress_callback(Progress(WriteProgress(info.written_rows, info.written_bytes)));

                if (stream_in)
                {
                    const BlockStreamProfileInfo & stream_in_info = stream_in->getProfileInfo();

                    /// NOTE: INSERT SELECT query contains zero metrics
                    elem.result_rows = stream_in_info.rows;
                    elem.result_bytes = stream_in_info.bytes;
                }
                else if (stream_out) /// will be used only for ordinary INSERT queries
                {
                    if (const auto * counting_stream = dynamic_cast<const CountingBlockOutputStream *>(stream_out))
                    {
                        /// NOTE: Redundancy. The same values could be extracted from process_list_elem->progress_out.query_settings = process_list_elem->progress_in
                        elem.result_rows = counting_stream->getProgress().read_rows;
                        elem.result_bytes = counting_stream->getProgress().read_bytes;
                    }
                }
                else if (query_pipeline)
                {
                    if (const auto * output_format = query_pipeline->getOutputFormat())
                    {
                        elem.result_rows = output_format->getResultRows();
                        elem.result_bytes = output_format->getResultBytes();
                    }
                }

                if (elem.read_rows != 0)
                {
                    LOG_INFO(&Poco::Logger::get("executeQuery"), "Read {} rows, {} in {} sec., {} rows/sec., {}/sec.",
                        elem.read_rows, ReadableSize(elem.read_bytes), elapsed_seconds,
                        static_cast<size_t>(elem.read_rows / elapsed_seconds),
                        ReadableSize(elem.read_bytes / elapsed_seconds));
                }

                elem.thread_ids = std::move(info.thread_ids);
                elem.profile_counters = std::move(info.profile_counters);

                if (log_queries && elem.type >= log_queries_min_type)
                {
                    if (auto query_log = context.getQueryLog())
                        query_log->add(elem);
                }

                if (auto opentelemetry_log = context.getOpenTelemetryLog())
                {
                    OpenTelemetrySpanLogElement span;
                    span.trace_id = context.getClientInfo().trace_id;
                    span.span_id = context.getClientInfo().span_id;
                    span.parent_span_id = context.getClientInfo().parent_span_id;
                    span.operation_name = "query";
                    span.start_time = elem.query_start_time;
                    span.finish_time = time(nullptr); // current time

                    // keep values synchonized to type enum in QueryLogElement::createBlock
                    span.attribute_names.push_back("status");
                    span.attribute_values.push_back("QueryFinish");

                    span.attribute_names.push_back("query");
                    span.attribute_values.push_back(elem.query);

                    span.attribute_names.push_back("query_id");
                    span.attribute_values.push_back(elem.client_info.current_query_id);

                    opentelemetry_log->add(span);
                }
            };

            auto exception_callback = [elem, &context, ast, log_queries, log_queries_min_type = settings.log_queries_min_type, quota(quota),
                    status_info_to_query_log] () mutable
            {
                if (quota)
                    quota->used(Quota::ERRORS, 1, /* check_exceeded = */ false);

                elem.type = QueryLogElementType::EXCEPTION_WHILE_PROCESSING;

                elem.event_time = time(nullptr);
                elem.query_duration_ms = 1000 * (elem.event_time - elem.query_start_time);
                elem.exception_code = getCurrentExceptionCode();
                elem.exception = getCurrentExceptionMessage(false);

                QueryStatus * process_list_elem = context.getProcessListElement();
                const Settings & current_settings = context.getSettingsRef();

                /// Update performance counters before logging to query_log
                CurrentThread::finalizePerformanceCounters();

                if (process_list_elem)
                {
                    QueryStatusInfo info = process_list_elem->getInfo(true, current_settings.log_profile_events, false);
                    status_info_to_query_log(elem, info, ast);
                }

                if (current_settings.calculate_text_stack_trace)
                    setExceptionStackTrace(elem);
                logException(context, elem);

                /// In case of exception we log internal queries also
                if (log_queries && elem.type >= log_queries_min_type)
                {
                    if (auto query_log = context.getQueryLog())
                        query_log->add(elem);
                }

                ProfileEvents::increment(ProfileEvents::FailedQuery);
                if (ast->as<ASTSelectQuery>() || ast->as<ASTSelectWithUnionQuery>())
                {
                    ProfileEvents::increment(ProfileEvents::FailedSelectQuery);
                }
                else if (ast->as<ASTInsertQuery>())
                {
                    ProfileEvents::increment(ProfileEvents::FailedInsertQuery);
                }

            };

            res.finish_callback = std::move(finish_callback);
            res.exception_callback = std::move(exception_callback);

            if (!internal && res.in)
            {
                std::stringstream log_str;
                log_str << "Query pipeline:\n";
                res.in->dumpTree(log_str);
                LOG_DEBUG(&Poco::Logger::get("executeQuery"), log_str.str());
            }
        }
    }
    catch (...)
    {
        if (!internal)
        {
            if (query_for_logging.empty())
                query_for_logging = prepareQueryForLogging(query, context);

            onExceptionBeforeStart(query_for_logging, context, current_time, ast);
        }

        throw;
    }

    return std::make_tuple(ast, std::move(res));
}


BlockIO executeQuery(
    const String & query,
    Context & context,
    bool internal,
    QueryProcessingStage::Enum stage,
    bool may_have_embedded_data)
{
    ASTPtr ast;
    BlockIO streams;
    std::tie(ast, streams) = executeQueryImpl(query.data(), query.data() + query.size(), context,
        internal, stage, !may_have_embedded_data, nullptr);

    if (const auto * ast_query_with_output = dynamic_cast<const ASTQueryWithOutput *>(ast.get()))
    {
        String format_name = ast_query_with_output->format
                ? getIdentifierName(ast_query_with_output->format)
                : context.getDefaultFormat();

        if (format_name == "Null")
            streams.null_format = true;
    }

    return streams;
}

BlockIO executeQuery(
        const String & query,
        Context & context,
        bool internal,
        QueryProcessingStage::Enum stage,
        bool may_have_embedded_data,
        bool allow_processors)
{
    BlockIO res = executeQuery(query, context, internal, stage, may_have_embedded_data);

    if (!allow_processors && res.pipeline.initialized())
        res.in = res.getInputStream();

    return res;
}


void executeQuery(
    ReadBuffer & istr,
    WriteBuffer & ostr,
    bool allow_into_outfile,
    Context & context,
    std::function<void(const String &, const String &, const String &, const String &)> set_result_details)
{
    PODArray<char> parse_buf;
    const char * begin;
    const char * end;

    /// If 'istr' is empty now, fetch next data into buffer.
    if (!istr.hasPendingData())
        istr.next();

    size_t max_query_size = context.getSettingsRef().max_query_size;

    bool may_have_tail;
    if (istr.buffer().end() - istr.position() > static_cast<ssize_t>(max_query_size))
    {
        /// If remaining buffer space in 'istr' is enough to parse query up to 'max_query_size' bytes, then parse inplace.
        begin = istr.position();
        end = istr.buffer().end();
        istr.position() += end - begin;
        /// Actually we don't know will query has additional data or not.
        /// But we can't check istr.eof(), because begin and end pointers will became invalid
        may_have_tail = true;
    }
    else
    {
        /// If not - copy enough data into 'parse_buf'.
        WriteBufferFromVector<PODArray<char>> out(parse_buf);
        LimitReadBuffer limit(istr, max_query_size + 1, false);
        copyData(limit, out);
        out.finalize();

        begin = parse_buf.data();
        end = begin + parse_buf.size();
        /// Can check stream for eof, because we have copied data
        may_have_tail = !istr.eof();
    }

    ASTPtr ast;
    BlockIO streams;

    std::tie(ast, streams) = executeQueryImpl(begin, end, context, false, QueryProcessingStage::Complete, may_have_tail, &istr);

    auto & pipeline = streams.pipeline;

    try
    {
        if (streams.out)
        {
            InputStreamFromASTInsertQuery in(ast, &istr, streams.out->getHeader(), context, nullptr);
            copyData(in, *streams.out);
        }

        if (streams.in)
        {
            /// FIXME: try to prettify this cast using `as<>()`
            const auto * ast_query_with_output = dynamic_cast<const ASTQueryWithOutput *>(ast.get());

            WriteBuffer * out_buf = &ostr;
            std::optional<WriteBufferFromFile> out_file_buf;
            if (ast_query_with_output && ast_query_with_output->out_file)
            {
                if (!allow_into_outfile)
                    throw Exception("INTO OUTFILE is not allowed", ErrorCodes::INTO_OUTFILE_NOT_ALLOWED);

                const auto & out_file = ast_query_with_output->out_file->as<ASTLiteral &>().value.safeGet<std::string>();
                out_file_buf.emplace(out_file, DBMS_DEFAULT_BUFFER_SIZE, O_WRONLY | O_EXCL | O_CREAT);
                out_buf = &*out_file_buf;
            }

            String format_name = ast_query_with_output && (ast_query_with_output->format != nullptr)
                ? getIdentifierName(ast_query_with_output->format)
                : context.getDefaultFormat();

            if (ast_query_with_output && ast_query_with_output->settings_ast)
                InterpreterSetQuery(ast_query_with_output->settings_ast, context).executeForCurrentContext();

            BlockOutputStreamPtr out = context.getOutputFormat(format_name, *out_buf, streams.in->getHeader());

            /// Save previous progress callback if any. TODO Do it more conveniently.
            auto previous_progress_callback = context.getProgressCallback();

            /// NOTE Progress callback takes shared ownership of 'out'.
            streams.in->setProgressCallback([out, previous_progress_callback] (const Progress & progress)
            {
                if (previous_progress_callback)
                    previous_progress_callback(progress);
                out->onProgress(progress);
            });

            if (set_result_details)
                set_result_details(context.getClientInfo().current_query_id, out->getContentType(), format_name, DateLUT::instance().getTimeZone());

            copyData(*streams.in, *out, [](){ return false; }, [&out](const Block &) { out->flush(); });
        }

        if (pipeline.initialized())
        {
            const ASTQueryWithOutput * ast_query_with_output = dynamic_cast<const ASTQueryWithOutput *>(ast.get());

            WriteBuffer * out_buf = &ostr;
            std::optional<WriteBufferFromFile> out_file_buf;
            if (ast_query_with_output && ast_query_with_output->out_file)
            {
                if (!allow_into_outfile)
                    throw Exception("INTO OUTFILE is not allowed", ErrorCodes::INTO_OUTFILE_NOT_ALLOWED);

                const auto & out_file = typeid_cast<const ASTLiteral &>(*ast_query_with_output->out_file).value.safeGet<std::string>();
                out_file_buf.emplace(out_file, DBMS_DEFAULT_BUFFER_SIZE, O_WRONLY | O_EXCL | O_CREAT);
                out_buf = &*out_file_buf;
            }

            String format_name = ast_query_with_output && (ast_query_with_output->format != nullptr)
                                 ? getIdentifierName(ast_query_with_output->format)
                                 : context.getDefaultFormat();

            if (ast_query_with_output && ast_query_with_output->settings_ast)
                InterpreterSetQuery(ast_query_with_output->settings_ast, context).executeForCurrentContext();

            if (!pipeline.isCompleted())
            {
                pipeline.addSimpleTransform([](const Block & header)
                {
                    return std::make_shared<MaterializingTransform>(header);
                });

                auto out = context.getOutputFormatProcessor(format_name, *out_buf, pipeline.getHeader());
                out->setAutoFlush();

                /// Save previous progress callback if any. TODO Do it more conveniently.
                auto previous_progress_callback = context.getProgressCallback();

                /// NOTE Progress callback takes shared ownership of 'out'.
                pipeline.setProgressCallback([out, previous_progress_callback] (const Progress & progress)
                {
                    if (previous_progress_callback)
                        previous_progress_callback(progress);
                    out->onProgress(progress);
                });

                if (set_result_details)
                    set_result_details(context.getClientInfo().current_query_id, out->getContentType(), format_name, DateLUT::instance().getTimeZone());

                pipeline.setOutputFormat(std::move(out));
            }
            else
            {
                pipeline.setProgressCallback(context.getProgressCallback());
            }

            {
                auto executor = pipeline.execute();
                executor->execute(pipeline.getNumThreads());
            }
        }
    }
    catch (...)
    {
        streams.onException();
        throw;
    }

    streams.onFinish();
}

}