ClickHouse/src/Interpreters/DuplicateOrderByVisitor.cpp
2023-02-19 23:30:05 +01:00

122 lines
3.3 KiB
C++

#include <Interpreters/DuplicateOrderByVisitor.h>
#include <Functions/FunctionFactory.h>
#include <AggregateFunctions/AggregateFunctionFactory.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTSetQuery.h>
#include <Parsers/ASTTablesInSelectQuery.h>
#include <Parsers/ASTOrderByElement.h>
#include <Common/typeid_cast.h>
namespace DB
{
namespace ErrorCodes
{
extern const int UNKNOWN_TYPE_OF_AST_NODE;
}
namespace
{
/// Checks if SELECT has stateful functions
class ASTFunctionStatefulData
{
public:
using TypeToVisit = ASTFunction;
ContextPtr context;
bool & is_stateful;
void visit(ASTFunction & ast_function, ASTPtr &)
{
auto aggregate_function_properties = AggregateFunctionFactory::instance().tryGetProperties(ast_function.name);
if (aggregate_function_properties && aggregate_function_properties->is_order_dependent)
{
is_stateful = true;
return;
}
const auto & function = FunctionFactory::instance().tryGet(ast_function.name, context);
if (function && function->isStateful())
{
is_stateful = true;
return;
}
}
};
using ASTFunctionStatefulMatcher = OneTypeMatcher<ASTFunctionStatefulData>;
using ASTFunctionStatefulVisitor = InDepthNodeVisitor<ASTFunctionStatefulMatcher, true>;
}
void DuplicateOrderByFromSubqueriesData::visit(ASTSelectQuery & select_query, ASTPtr &)
{
if (done)
return;
done = true;
if (select_query.orderBy())
{
/// If we have limits then the ORDER BY is non-removable.
if (select_query.limitBy()
|| select_query.limitByOffset()
|| select_query.limitByLength()
|| select_query.limitLength()
|| select_query.limitOffset())
{
return;
}
/// If ORDER BY contains filling (in addition to sorting) it is non-removable.
for (const auto & child : select_query.orderBy()->children)
{
auto * ast = child->as<ASTOrderByElement>();
if (!ast || ast->children.empty())
throw Exception(ErrorCodes::UNKNOWN_TYPE_OF_AST_NODE, "Bad ORDER BY expression AST");
if (ast->with_fill)
return;
}
select_query.setExpression(ASTSelectQuery::Expression::ORDER_BY, nullptr);
}
}
void DuplicateOrderByData::visit(ASTSelectQuery & select_query, ASTPtr &)
{
if (select_query.orderBy() || select_query.groupBy())
{
for (auto & elem : select_query.children)
{
if (elem->as<ASTExpressionList>())
{
bool is_stateful = false;
ASTFunctionStatefulVisitor::Data data{context, is_stateful};
ASTFunctionStatefulVisitor(data).visit(elem);
if (is_stateful)
return;
}
}
if (auto select_table_ptr = select_query.tables())
{
if (auto * select_table = select_table_ptr->as<ASTTablesInSelectQuery>())
{
if (!select_table->children.empty())
{
DuplicateOrderByFromSubqueriesVisitor::Data data{false};
DuplicateOrderByFromSubqueriesVisitor(data).visit(select_table->children[0]);
}
}
}
}
}
}