exduckdb

#include "duckdb/optimizer/optimizer.hpp"
#include "duckdb/main/query_profiler.hpp"
#include "duckdb/execution/expression_executor.hpp"
#include "duckdb/main/client_context.hpp"
#include "duckdb/optimizer/column_lifetime_optimizer.hpp"
#include "duckdb/optimizer/common_aggregate_optimizer.hpp"
#include "duckdb/optimizer/cse_optimizer.hpp"
#include "duckdb/optimizer/deliminator.hpp"
#include "duckdb/optimizer/expression_heuristics.hpp"
#include "duckdb/optimizer/filter_pullup.hpp"
#include "duckdb/optimizer/filter_pushdown.hpp"
#include "duckdb/optimizer/in_clause_rewriter.hpp"
#include "duckdb/optimizer/join_order_optimizer.hpp"
#include "duckdb/optimizer/regex_range_filter.hpp"
#include "duckdb/optimizer/remove_unused_columns.hpp"
#include "duckdb/optimizer/rule/list.hpp"
#include "duckdb/optimizer/statistics_propagator.hpp"
#include "duckdb/optimizer/topn_optimizer.hpp"
#include "duckdb/planner/binder.hpp"
#include "duckdb/main/config.hpp"

#include "duckdb/optimizer/rule/in_clause_simplification.hpp"

namespace duckdb {

Optimizer::Optimizer(Binder &binder, ClientContext &context) : context(context), binder(binder), rewriter(context) {
	rewriter.rules.push_back(make_unique<ConstantFoldingRule>(rewriter));
	rewriter.rules.push_back(make_unique<DistributivityRule>(rewriter));
	rewriter.rules.push_back(make_unique<ArithmeticSimplificationRule>(rewriter));
	rewriter.rules.push_back(make_unique<CaseSimplificationRule>(rewriter));
	rewriter.rules.push_back(make_unique<ConjunctionSimplificationRule>(rewriter));
	rewriter.rules.push_back(make_unique<DatePartSimplificationRule>(rewriter));
	rewriter.rules.push_back(make_unique<ComparisonSimplificationRule>(rewriter));
	rewriter.rules.push_back(make_unique<InClauseSimplificationRule>(rewriter));
	rewriter.rules.push_back(make_unique<MoveConstantsRule>(rewriter));
	rewriter.rules.push_back(make_unique<LikeOptimizationRule>(rewriter));
	rewriter.rules.push_back(make_unique<EmptyNeedleRemovalRule>(rewriter));
	rewriter.rules.push_back(make_unique<EnumComparisonRule>(rewriter));

#ifdef DEBUG
	for (auto &rule : rewriter.rules) {
		// root not defined in rule
		D_ASSERT(rule->root);
	}
#endif
}

void Optimizer::RunOptimizer(OptimizerType type, const std::function<void()> &callback) {
	auto &config = DBConfig::GetConfig(context);
	if (config.disabled_optimizers.find(type) != config.disabled_optimizers.end()) {
		// optimizer is marked as disabled: skip
		return;
	}
	context.profiler->StartPhase(OptimizerTypeToString(type));
	callback();
	context.profiler->EndPhase();
}

unique_ptr<LogicalOperator> Optimizer::Optimize(unique_ptr<LogicalOperator> plan) {
	// first we perform expression rewrites using the ExpressionRewriter
	// this does not change the logical plan structure, but only simplifies the expression trees
	RunOptimizer(OptimizerType::EXPRESSION_REWRITER, [&]() { rewriter.VisitOperator(*plan); });

	// perform filter pullup
	RunOptimizer(OptimizerType::FILTER_PULLUP, [&]() {
		FilterPullup filter_pullup;
		plan = filter_pullup.Rewrite(move(plan));
	});

	// perform filter pushdown
	RunOptimizer(OptimizerType::FILTER_PUSHDOWN, [&]() {
		FilterPushdown filter_pushdown(*this);
		plan = filter_pushdown.Rewrite(move(plan));
	});

	RunOptimizer(OptimizerType::REGEX_RANGE, [&]() {
		RegexRangeFilter regex_opt;
		plan = regex_opt.Rewrite(move(plan));
	});

	RunOptimizer(OptimizerType::IN_CLAUSE, [&]() {
		InClauseRewriter rewriter(*this);
		plan = rewriter.Rewrite(move(plan));
	});

	// then we perform the join ordering optimization
	// this also rewrites cross products + filters into joins and performs filter pushdowns
	RunOptimizer(OptimizerType::JOIN_ORDER, [&]() {
		JoinOrderOptimizer optimizer(context);
		plan = optimizer.Optimize(move(plan));
	});

	// removes any redundant DelimGets/DelimJoins
	RunOptimizer(OptimizerType::DELIMINATOR, [&]() {
		Deliminator deliminator;
		plan = deliminator.Optimize(move(plan));
	});

	RunOptimizer(OptimizerType::UNUSED_COLUMNS, [&]() {
		RemoveUnusedColumns unused(binder, context, true);
		unused.VisitOperator(*plan);
	});

	// perform statistics propagation
	RunOptimizer(OptimizerType::STATISTICS_PROPAGATION, [&]() {
		StatisticsPropagator propagator(context);
		propagator.PropagateStatistics(plan);
	});

	// then we extract common subexpressions inside the different operators
	RunOptimizer(OptimizerType::COMMON_SUBEXPRESSIONS, [&]() {
		CommonSubExpressionOptimizer cse_optimizer(binder);
		cse_optimizer.VisitOperator(*plan);
	});

	RunOptimizer(OptimizerType::COMMON_AGGREGATE, [&]() {
		CommonAggregateOptimizer common_aggregate;
		common_aggregate.VisitOperator(*plan);
	});

	RunOptimizer(OptimizerType::COLUMN_LIFETIME, [&]() {
		ColumnLifetimeAnalyzer column_lifetime(true);
		column_lifetime.VisitOperator(*plan);
	});

	// transform ORDER BY + LIMIT to TopN
	RunOptimizer(OptimizerType::TOP_N, [&]() {
		TopN topn;
		plan = topn.Optimize(move(plan));
	});

	// apply simple expression heuristics to get an initial reordering
	RunOptimizer(OptimizerType::REORDER_FILTER, [&]() {
		ExpressionHeuristics expression_heuristics(*this);
		plan = expression_heuristics.Rewrite(move(plan));
	});

	return plan;
}

} // namespace duckdb