ClickHouse

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#include <Processors/QueryPlan/Optimizations/Optimizations.h>
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#include <Processors/QueryPlan/ExpressionStep.h>
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#include <Processors/QueryPlan/FilterStep.h>
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#include <Processors/QueryPlan/ReadFromMergeTree.h>
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#include <Processors/QueryPlan/SourceStepWithFilter.h>
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namespace DB::QueryPlanOptimizations
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{
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void optimizePrimaryKeyCondition(const Stack & stack)
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{
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    const auto & frame = stack.back();
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    auto * source_step_with_filter = dynamic_cast<SourceStepWithFilter *>(frame.node->step.get());
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    if (!source_step_with_filter)
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        return;
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    const auto & storage_prewhere_info = source_step_with_filter->getPrewhereInfo();
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    if (storage_prewhere_info)
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    {
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        source_step_with_filter->addFilter(storage_prewhere_info->prewhere_actions, storage_prewhere_info->prewhere_column_name);
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        if (storage_prewhere_info->row_level_filter)
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            source_step_with_filter->addFilter(storage_prewhere_info->row_level_filter, storage_prewhere_info->row_level_column_name);
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    }
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    for (auto iter = stack.rbegin() + 1; iter != stack.rend(); ++iter)
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    {
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        if (auto * filter_step = typeid_cast<FilterStep *>(iter->node->step.get()))
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            source_step_with_filter->addFilter(filter_step->getExpression(), filter_step->getFilterColumnName());
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        /// Note: actually, plan optimizations merge Filter and Expression steps.
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        /// Ideally, chain should look like (Expression -> ...) -> (Filter -> ...) -> ReadFromStorage,
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        /// So this is likely not needed.
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        else if (typeid_cast<ExpressionStep *>(iter->node->step.get()))
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            continue;
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        else
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            break;
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    }
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    source_step_with_filter->applyFilters();
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}
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}
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