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Refactor tryPushDownFilter optimization.

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This commit is contained in:
Nikolai Kochetov 2021-02-20 19:25:47 +03:00
parent f0396661b3
commit 2ae0b47edb
1 changed files with 18 additions and 7 deletions
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25
src/Processors/QueryPlan/Optimizations/filterPushDown.cpp
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@ -56,19 +56,30 @@ static size_t tryAddNewFilterStep(
if ((*it)->result_name == filter_column_name)
break;
const bool found_filter_column = it != expression->getIndex().end();
if (!found_filter_column && removes_filter)
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Filter column {} was removed from ActionsDAG but it is needed in result. DAG:\n{}",
filter_column_name, expression->dumpDAG());
const bool filter_is_constant = found_filter_column && (*it)->column && isColumnConst(*(*it)->column);
if (!found_filter_column || filter_is_constant)
/// This means that all predicates of filter were pused down.
/// Replace current actions to expression, as we don't need to filter anything.
parent = std::make_unique<ExpressionStep>(child->getOutputStream(), expression);
if (it == expression->getIndex().end())
{
if (!removes_filter)
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Filter column {} was removed from ActionsDAG but it is needed in result. DAG:\n{}",
filter_column_name, expression->dumpDAG());
/// Filter was removed after split.
// std::cerr << "replacing to expr because filter " << filter_column_name << " was removed\n";
parent = std::make_unique<ExpressionStep>(child->getOutputStream(), expression);
}
else if ((*it)->column && isColumnConst(*(*it)->column))
{
// std::cerr << "replacing to expr because filter is const\n";
/// Filter column was replaced to constant.
parent = std::make_unique<ExpressionStep>(child->getOutputStream(), expression);
}