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Fix limit.

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This commit is contained in:
Nikolai Kochetov 2022-11-09 18:12:01 +00:00
parent 3c3771a8d7
commit ff65ca42ad
1 changed files with 23 additions and 4 deletions
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27
src/Processors/QueryPlan/Optimizations/optimizeReadInOrder.cpp
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@ -147,13 +147,16 @@ void appendExpression(ActionsDAGPtr & dag, const ActionsDAGPtr & expression)
/// This function builds a common DAG which is a gerge of DAGs from Filter and Expression steps chain.
/// Additionally, build a set of fixed columns.
void buildSortingDAG(QueryPlan::Node & node, ActionsDAGPtr & dag, FixedColumns & fixed_columns)
void buildSortingDAG(QueryPlan::Node & node, ActionsDAGPtr & dag, FixedColumns & fixed_columns, size_t & limit)
{
IQueryPlanStep * step = node.step.get();
if (auto * reading = typeid_cast<ReadFromMergeTree *>(step))
{
if (const auto * prewhere_info = reading->getPrewhereInfo())
{
/// Should ignore limit if there is filtering.
limit = 0;
if (prewhere_info->prewhere_actions)
{
//std::cerr << "====== Adding prewhere " << std::endl;
@ -168,13 +171,24 @@ void buildSortingDAG(QueryPlan::Node & node, ActionsDAGPtr & dag, FixedColumns &
if (node.children.size() != 1)
return;
buildSortingDAG(*node.children.front(), dag, fixed_columns);
buildSortingDAG(*node.children.front(), dag, fixed_columns, limit);
if (auto * expression = typeid_cast<ExpressionStep *>(step))
appendExpression(dag, expression->getExpression());
{
const auto & actions = expression->getExpression();
/// Should ignore limit because arrayJoin() can reduce the number of rows in case of empty array.
if (actions->hasArrayJoin())
limit = 0;
appendExpression(dag, actions);
}
if (auto * filter = typeid_cast<FilterStep *>(step))
{
/// Should ignore limit if there is filtering.
limit = 0;
appendExpression(dag, filter->getExpression());
if (const auto * filter_expression = dag->tryFindInOutputs(filter->getFilterColumnName()))
appendFixedColumnsFromFilterExpression(*filter_expression, fixed_columns);
@ -182,6 +196,11 @@ void buildSortingDAG(QueryPlan::Node & node, ActionsDAGPtr & dag, FixedColumns &
if (auto * array_join = typeid_cast<ArrayJoinStep *>(step))
{
/// Should ignore limit because ARRAY JOIN can reduce the number of rows in case of empty array.
/// But in case of LEFT ARRAY JOIN the result number of rows is always bigger.
if (!array_join->arrayJoin()->is_left)
limit = 0;
const auto & array_joined_columns = array_join->arrayJoin()->columns;
/// Remove array joined columns from outputs.
@ -725,7 +744,7 @@ InputOrderInfoPtr buildInputOrderInfo(SortingStep & sorting, QueryPlan::Node & n
ActionsDAGPtr dag;
FixedColumns fixed_columns;
buildSortingDAG(node, dag, fixed_columns);
buildSortingDAG(node, dag, fixed_columns, limit);
if (dag && !fixed_columns.empty())
enreachFixedColumns(*dag, fixed_columns);