Method check

src/Optimizer/QueryUseOptimizerChecker.cpp:105–216

}

bool QueryUseOptimizerChecker::check(ASTPtr node, ContextMutablePtr context, bool throw_exception)
{
    if (!node || (!context->getSettingsRef().enable_optimizer))
    {
        turnOffOptimizer(context, node);
        return false;
    }

    // Optimizer only work for Server.
    // for example INSERT INTO parallel_replicas_backup(d, x, u, s) SELECT d, x, u, s FROM parallel_replicas;
    // will execute query : INSERT INTO test.parallel_replicas_backup_4313395779120660490 (d, x, u, s) SELECT d, x, u, s FROM test.parallel_replicas )
    // will execute query : SELECT d, x, u, s FROM test.parallel_replicas_4313395779120660490
    // in worker.
    if (context->getServerType() == ServerType::cnch_worker)
    {
        turnOffOptimizer(context, node);
        return false;
    }

    if (!context->getSettingsRef().enable_optimizer && context->getSettingsRef().enable_distributed_output)
        throw Exception("Distributed output in non-optimizer mode is not supported, please enable optimizer.", ErrorCodes::UNSUPPORTED_PARAMETER);

    String reason;
    if (auto * explain = node->as<ASTExplainQuery>())
    {
        bool explain_plan = explain->getKind() == ASTExplainQuery::ExplainKind::OptimizerPlan
            || explain->getKind() == ASTExplainQuery::ExplainKind::QueryPlan
            || explain->getKind() == ASTExplainQuery::ExplainKind::QueryPipeline
            || explain->getKind() ==  ASTExplainQuery::AnalyzedSyntax
            || explain->getKind() ==  ASTExplainQuery::DistributedAnalyze
            || explain->getKind() ==  ASTExplainQuery::LogicalAnalyze
            || explain->getKind() ==  ASTExplainQuery::PipelineAnalyze
            || explain->getKind() ==  ASTExplainQuery::Distributed
            || explain->getKind() ==  ASTExplainQuery::TraceOptimizerRule
            || explain->getKind() ==  ASTExplainQuery::TraceOptimizer
            || explain->getKind() ==  ASTExplainQuery::MetaData;
        if (!explain_plan)
            reason = "unsupported explain type";
        return explain_plan && check(explain->getExplainedQuery(), context, throw_exception);
    }
    if (auto * prepare = node->as<ASTCreatePreparedStatementQuery>())
    {
        return check(prepare->getQuery(), context, throw_exception);
    }


    bool support = false;

    if (node->as<ASTSelectQuery>() || node->as<ASTSelectWithUnionQuery>() || node->as<ASTSelectIntersectExceptQuery>())
    {
        // disable system query, table function, no merge tree table
        NameSet with_tables;

        QueryUseOptimizerVisitor checker;
        QueryUseOptimizerContext check_context{.context = context};
        try
        {
            support = ASTVisitorUtil::accept(node, checker, check_context);