Method isQueryWithSampling

src/Processors/QueryPlan/ReadFromMergeTree.cpp:3147–3157

}

bool ReadFromMergeTree::isQueryWithSampling() const
{
    if (context->getSettingsRef()[Setting::parallel_replicas_count] > 1 && data.supportsSampling())
        return true;

    if (query_info.table_expression_modifiers)
        return query_info.table_expression_modifiers->getSampleSizeRatio() != std::nullopt;

    const auto & select = query_info.query->as<ASTSelectQuery &>();
    return select.sampleSize() != nullptr;
}

Pipe ReadFromMergeTree::spreadMarkRanges(
    RangesInDataParts && parts_with_ranges,