ClickHouse/src/Interpreters/InterpreterSelectQueryAnalyzer.cpp

#include <Interpreters/InterpreterSelectQueryAnalyzer.h>

#include <Parsers/ASTSelectWithUnionQuery.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTExpressionList.h>
#include <Parsers/ASTSubquery.h>

#include <DataTypes/DataTypesNumber.h>

#include <Processors/QueryPlan/IQueryPlanStep.h>
#include <Processors/QueryPlan/QueryPlan.h>
#include <Processors/QueryPlan/Optimizations/QueryPlanOptimizationSettings.h>
#include <QueryPipeline/QueryPipelineBuilder.h>

#include <Storages/IStorage.h>

#include <Analyzer/QueryTreeBuilder.h>
#include <Analyzer/QueryTreePassManager.h>
#include <Analyzer/IdentifierNode.h>
#include <Analyzer/QueryNode.h>
#include <Analyzer/UnionNode.h>
#include <Analyzer/TableNode.h>
#include <Analyzer/TableFunctionNode.h>
#include <Analyzer/Utils.h>

#include <Interpreters/Context.h>
#include <Interpreters/QueryLog.h>

namespace DB
{

namespace ErrorCodes
{
    extern const int UNSUPPORTED_METHOD;
}

namespace
{

ASTPtr normalizeAndValidateQuery(const ASTPtr & query)
{
    if (query->as<ASTSelectWithUnionQuery>() || query->as<ASTSelectQuery>())
    {
        return query;
    }
    else if (auto * subquery = query->as<ASTSubquery>())
    {
        return subquery->children[0];
    }
    else
    {
        throw Exception(ErrorCodes::UNSUPPORTED_METHOD,
            "Expected ASTSelectWithUnionQuery or ASTSelectQuery. Actual {}",
            query->formatForErrorMessage());
    }
}

ContextMutablePtr buildContext(const ContextPtr & context, const SelectQueryOptions & select_query_options)
{
    auto result_context = Context::createCopy(context);

    if (select_query_options.shard_num)
        result_context->addSpecialScalar(
            "_shard_num",
            Block{{DataTypeUInt32().createColumnConst(1, *select_query_options.shard_num), std::make_shared<DataTypeUInt32>(), "_shard_num"}});
    if (select_query_options.shard_count)
        result_context->addSpecialScalar(
            "_shard_count",
            Block{{DataTypeUInt32().createColumnConst(1, *select_query_options.shard_count), std::make_shared<DataTypeUInt32>(), "_shard_count"}});

    return result_context;
}

void replaceStorageInQueryTree(QueryTreeNodePtr & query_tree, const ContextPtr & context, const StoragePtr & storage)
{
    auto query_to_replace_table_expression = query_tree;
    QueryTreeNodePtr table_expression_to_replace;

    while (!table_expression_to_replace)
    {
        if (auto * union_node = query_to_replace_table_expression->as<UnionNode>())
            query_to_replace_table_expression = union_node->getQueries().getNodes().at(0);

        auto & query_to_replace_table_expression_typed = query_to_replace_table_expression->as<QueryNode &>();
        auto left_table_expression = extractLeftTableExpression(query_to_replace_table_expression_typed.getJoinTree());
        auto left_table_expression_node_type = left_table_expression->getNodeType();

        switch (left_table_expression_node_type)
        {
            case QueryTreeNodeType::QUERY:
            case QueryTreeNodeType::UNION:
            {
                query_to_replace_table_expression = std::move(left_table_expression);
                break;
            }
            case QueryTreeNodeType::TABLE:
            case QueryTreeNodeType::TABLE_FUNCTION:
            case QueryTreeNodeType::IDENTIFIER:
            {
                table_expression_to_replace = std::move(left_table_expression);
                break;
            }
            default:
            {
                throw Exception(ErrorCodes::UNSUPPORTED_METHOD,
                    "Expected table, table function or identifier node to replace with storage. Actual {}",
                    left_table_expression->formatASTForErrorMessage());
            }
        }
    }

    auto replacement_table_expression = std::make_shared<TableNode>(storage, context);
    std::optional<TableExpressionModifiers> table_expression_modifiers;

    if (auto * table_node = table_expression_to_replace->as<TableNode>())
        table_expression_modifiers = table_node->getTableExpressionModifiers();
    else if (auto * table_function_node = table_expression_to_replace->as<TableFunctionNode>())
        table_expression_modifiers = table_function_node->getTableExpressionModifiers();
    else if (auto * identifier_node = table_expression_to_replace->as<IdentifierNode>())
        table_expression_modifiers = identifier_node->getTableExpressionModifiers();

    if (table_expression_modifiers)
        replacement_table_expression->setTableExpressionModifiers(*table_expression_modifiers);

    query_tree = query_tree->cloneAndReplace(table_expression_to_replace, std::move(replacement_table_expression));
}

QueryTreeNodePtr buildQueryTreeAndRunPasses(const ASTPtr & query,
    const SelectQueryOptions & select_query_options,
    const ContextPtr & context,
    const StoragePtr & storage)
{
    auto query_tree = buildQueryTree(query, context);

    QueryTreePassManager query_tree_pass_manager(context);
    addQueryTreePasses(query_tree_pass_manager);

    /// We should not apply any query tree level optimizations on shards
    /// because it can lead to a changed header.
    if (select_query_options.ignore_ast_optimizations
        || context->getClientInfo().query_kind == ClientInfo::QueryKind::SECONDARY_QUERY)
        query_tree_pass_manager.run(query_tree, 1 /*up_to_pass_index*/);
    else
        query_tree_pass_manager.run(query_tree);

    if (storage)
        replaceStorageInQueryTree(query_tree, context, storage);

    return query_tree;
}

}

InterpreterSelectQueryAnalyzer::InterpreterSelectQueryAnalyzer(
    const ASTPtr & query_,
    const ContextPtr & context_,
    const SelectQueryOptions & select_query_options_)
    : query(normalizeAndValidateQuery(query_))
    , context(buildContext(context_, select_query_options_))
    , select_query_options(select_query_options_)
    , query_tree(buildQueryTreeAndRunPasses(query, select_query_options, context, nullptr /*storage*/))
    , planner(query_tree, select_query_options)
{
}

InterpreterSelectQueryAnalyzer::InterpreterSelectQueryAnalyzer(
    const ASTPtr & query_,
    const ContextPtr & context_,
    const StoragePtr & storage_,
    const SelectQueryOptions & select_query_options_)
    : query(normalizeAndValidateQuery(query_))
    , context(buildContext(context_, select_query_options_))
    , select_query_options(select_query_options_)
    , query_tree(buildQueryTreeAndRunPasses(query, select_query_options, context, storage_))
    , planner(query_tree, select_query_options)
{
}

InterpreterSelectQueryAnalyzer::InterpreterSelectQueryAnalyzer(
    const QueryTreeNodePtr & query_tree_,
    const ContextPtr & context_,
    const SelectQueryOptions & select_query_options_)
    : query(query_tree_->toAST())
    , context(buildContext(context_, select_query_options_))
    , select_query_options(select_query_options_)
    , query_tree(query_tree_)
    , planner(query_tree_, select_query_options_)
{
}

Block InterpreterSelectQueryAnalyzer::getSampleBlock(const ASTPtr & query,
    const ContextPtr & context,
    const SelectQueryOptions & select_query_options)
{
    auto select_query_options_copy = select_query_options;
    select_query_options_copy.only_analyze = true;
    InterpreterSelectQueryAnalyzer interpreter(query, context, select_query_options_copy);

    return interpreter.getSampleBlock();
}

Block InterpreterSelectQueryAnalyzer::getSampleBlock(const QueryTreeNodePtr & query_tree,
    const ContextPtr & context,
    const SelectQueryOptions & select_query_options)
{
    auto select_query_options_copy = select_query_options;
    select_query_options_copy.only_analyze = true;
    InterpreterSelectQueryAnalyzer interpreter(query_tree, context, select_query_options);

    return interpreter.getSampleBlock();
}

Block InterpreterSelectQueryAnalyzer::getSampleBlock()
{
    planner.buildQueryPlanIfNeeded();
    return planner.getQueryPlan().getCurrentDataStream().header;
}

BlockIO InterpreterSelectQueryAnalyzer::execute()
{
    auto pipeline_builder = buildQueryPipeline();

    BlockIO result;
    result.pipeline = QueryPipelineBuilder::getPipeline(std::move(pipeline_builder));

    if (!select_query_options.ignore_quota && select_query_options.to_stage == QueryProcessingStage::Complete)
        result.pipeline.setQuota(context->getQuota());

    return result;
}

QueryPlan & InterpreterSelectQueryAnalyzer::getQueryPlan()
{
    planner.buildQueryPlanIfNeeded();
    return planner.getQueryPlan();
}

QueryPlan && InterpreterSelectQueryAnalyzer::extractQueryPlan() &&
{
    planner.buildQueryPlanIfNeeded();
    return std::move(planner).extractQueryPlan();
}

QueryPipelineBuilder InterpreterSelectQueryAnalyzer::buildQueryPipeline()
{
    planner.buildQueryPlanIfNeeded();
    auto & query_plan = planner.getQueryPlan();

    auto optimization_settings = QueryPlanOptimizationSettings::fromContext(context);
    auto build_pipeline_settings = BuildQueryPipelineSettings::fromContext(context);

    return std::move(*query_plan.buildQueryPipeline(optimization_settings, build_pipeline_settings));
}

void InterpreterSelectQueryAnalyzer::addStorageLimits(const StorageLimitsList & storage_limits)
{
    planner.addStorageLimits(storage_limits);
}

}