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dbms: Server: feature development [#METR-14875]

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This commit is contained in:
Alexey Arno 2015-02-18 16:16:59 +03:00
parent 2106412813
commit 6fa2f82579
1 changed files with 37 additions and 25 deletions
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62
dbms/src/Interpreters/LogicalExpressionsOptimizer.cpp
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@ -5,6 +5,8 @@
#include <DB/Parsers/ASTLiteral.h>
#include <DB/Parsers/queryToString.h>
#include <DB/Core/ErrorCodes.h>
#include <deque>
namespace DB
@ -15,8 +17,7 @@ LogicalOrWithLeftHandSide::LogicalOrWithLeftHandSide(ASTFunction * or_function_,
{
}
bool operator<(const LogicalOrWithLeftHandSide & lhs,
const LogicalOrWithLeftHandSide & rhs)
bool operator<(const LogicalOrWithLeftHandSide & lhs, const LogicalOrWithLeftHandSide & rhs)
{
std::ptrdiff_t res1 = lhs.or_function - rhs.or_function;
if (res1 < 0)
@ -79,9 +80,6 @@ void LogicalExpressionsOptimizer::collectDisjunctiveEqualityChains()
auto function = typeid_cast<ASTFunction *>(&*to_node);
if ((function != nullptr) && (function->name == "or") && (function->children.size() == 1))
{
if (!from_node.isNull())
parent_map[function].push_back(from_node.get());
auto expression_list = typeid_cast<ASTExpressionList *>(&*(function->children[0]));
if (expression_list != nullptr)
{
@ -94,7 +92,7 @@ void LogicalExpressionsOptimizer::collectDisjunctiveEqualityChains()
auto equals_expression_list = typeid_cast<ASTExpressionList *>(&*(equals->children[0]));
if ((equals_expression_list != nullptr) && (equals_expression_list->children.size() == 2))
{
// Равенство c = xk
/// Равенство expr = xN.
auto expr_lhs = queryToString(equals_expression_list->children[0]);
auto literal = typeid_cast<ASTLiteral *>(&*(equals_expression_list->children[1]));
@ -108,6 +106,9 @@ void LogicalExpressionsOptimizer::collectDisjunctiveEqualityChains()
}
}
}
if (!from_node.isNull() && found)
parent_map[function].push_back(from_node.get());
}
if (!found)
@ -174,22 +175,31 @@ LogicalExpressionsOptimizer::ASTFunctionPtr LogicalExpressionsOptimizer::createI
return in_function;
}
namespace
{
ASTs & getOrExpressionOperands(const LogicalOrWithLeftHandSide & logical_or_with_lhs)
{
auto or_function = logical_or_with_lhs.or_function;
auto expression_list = static_cast<ASTExpressionList *>(&*(or_function->children[0]));
return expression_list->children;
}
}
void LogicalExpressionsOptimizer::putInExpression(const DisjunctiveEqualityChain & chain, ASTFunctionPtr in_expression)
{
const auto & logical_or_with_lhs = chain.first;
const auto & equalities = chain.second;
auto or_function = logical_or_with_lhs.or_function;
auto expression_list = static_cast<ASTExpressionList *>(&*(or_function->children[0]));
auto & children = expression_list->children;
auto & operands = getOrExpressionOperands(logical_or_with_lhs);
operands.push_back(in_expression);
children.push_back(in_expression);
auto it = std::remove_if(children.begin(), children.end(), [&](const ASTPtr & node)
auto it = std::remove_if(operands.begin(), operands.end(), [&](const ASTPtr & node)
{
return std::binary_search(equalities.begin(), equalities.end(), node.get());
});
children.erase(it, children.end());
operands.erase(it, operands.end());
}
void LogicalExpressionsOptimizer::fixBrokenOrExpressions()
@ -197,29 +207,31 @@ void LogicalExpressionsOptimizer::fixBrokenOrExpressions()
for (const auto & chain : disjunctive_equalities_map)
{
const auto & logical_or_with_lhs = chain.first;
const auto & equalities = chain.second;
auto or_function = logical_or_with_lhs.or_function;
auto expression_list = static_cast<ASTExpressionList *>(&*(or_function->children[0]));
auto & children = expression_list->children;
auto & operands = getOrExpressionOperands(logical_or_with_lhs);
if (children.size() == 1)
if (operands.size() == 1)
{
auto & parents = parent_map[or_function];
auto it = parent_map.find(or_function);
if (it == parent_map.end())
throw Exception("Parent node information is corrupted", ErrorCodes::LOGICAL_ERROR);
auto & parents = it->second;
for (auto & parent : parents)
{
parent->children.push_back(children[0]);
parent->children.push_back(operands[0]);
auto it = std::remove(parent->children.begin(), parent->children.end(), or_function);
parent->children.erase(it, parent->children.end());
}
/// Если узел OR был корнем выражения WHERE, PREWHERE или HAVING, то следует обновить этот корень.
/// Из-за того, что имеем дело с направленным ациклическим графом, надо проверить все случаи.
if (or_function == select_query->where_expression.get())
select_query->where_expression = children[0];
else if (or_function == select_query->prewhere_expression.get())
select_query->prewhere_expression = children[0];
else if (or_function == select_query->having_expression.get())
select_query->having_expression = children[0];
select_query->where_expression = operands[0];
if (or_function == select_query->prewhere_expression.get())
select_query->prewhere_expression = operands[0];
if (or_function == select_query->having_expression.get())
select_query->having_expression = operands[0];
}
}
}