more fixes

src/Processors/QueryPlan/Optimizations/liftUpFunctions.cpp

@@ -2,35 +2,48 @@
 #include <Processors/QueryPlan/ExpressionStep.h>
 #include <Processors/QueryPlan/Optimizations/Optimizations.h>
 #include <Processors/QueryPlan/SortingStep.h>
+#include <Common/Exception.h>
 
-#include <base/logger_useful.h>
-#include <Poco/Logger.h>
+namespace DB
+{
+namespace ErrorCodes
+{
+    extern const int LOGICAL_ERROR;
+}
+}
 
-namespace DB::QueryPlanOptimizations
+namespace
 {
 
-void swapSortingAndUnneededCalculations(QueryPlan::Node * parent_node, ActionsDAGPtr && unneeded_for_sorting)
+void swapSortingAndUnneededCalculations(DB::QueryPlan::Node * parent_node, DB::ActionsDAGPtr && unneeded_for_sorting)
 {
-    QueryPlan::Node * child_node = parent_node->children.front();
+    DB::QueryPlan::Node * child_node = parent_node->children.front();
 
     auto & parent_step = parent_node->step;
     auto & child_step = child_node->step;
-    auto * sorting_step = typeid_cast<SortingStep *>(parent_step.get());
+    auto * sorting_step = typeid_cast<DB::SortingStep *>(parent_step.get());
 
     // Sorting -> Expression
     std::swap(parent_step, child_step);
     // Expression -> Sorting
 
-    sorting_step->updateInputStream(child_node->children.at(0)->step->getOutputStream());
-    auto input_header = sorting_step->getInputStreams().at(0).header;
+    if (child_node->children.size() != 1)
+        throw DB::Exception(DB::ErrorCodes::LOGICAL_ERROR, "SortingStep is expected to have only one input stream.");
+    sorting_step->updateInputStream(child_node->children.front()->step->getOutputStream());
+    auto input_header = sorting_step->getInputStreams().front().header;
     sorting_step->updateOutputStream(std::move(input_header));
 
     auto description = parent_node->step->getStepDescription();
-    parent_step = std::make_unique<ExpressionStep>(child_step->getOutputStream(), std::move(unneeded_for_sorting));
+    parent_step = std::make_unique<DB::ExpressionStep>(child_step->getOutputStream(), std::move(unneeded_for_sorting));
     parent_step->setStepDescription(description + " [lifted up part]");
     // UnneededCalculations -> Sorting
 }
 
+}
+
+namespace DB::QueryPlanOptimizations
+{
+
 size_t tryExecuteFunctionsAfterSorting(QueryPlan::Node * parent_node, QueryPlan::Nodes & nodes)
 {
     if (parent_node->children.size() != 1)
@@ -55,12 +68,15 @@ size_t tryExecuteFunctionsAfterSorting(QueryPlan::Node * parent_node, QueryPlan:
     if (unneeded_for_sorting->trivial())
         return 0;
 
+    if (child_node->children.size() != 1)
+        throw DB::Exception(DB::ErrorCodes::LOGICAL_ERROR, "ExpressionStep is expected to have only one input stream.");
+
     // Sorting (parent_node) -> Expression (child_node)
     auto & node_with_needed = nodes.emplace_back();
     std::swap(node_with_needed.children, child_node->children);
     child_node->children = {&node_with_needed};
     node_with_needed.step
-        = std::make_unique<ExpressionStep>(node_with_needed.children.at(0)->step->getOutputStream(), std::move(needed_for_sorting));
+        = std::make_unique<ExpressionStep>(node_with_needed.children.front()->step->getOutputStream(), std::move(needed_for_sorting));
     node_with_needed.step->setStepDescription(child_step->getStepDescription());
 
     // Sorting (parent_node) -> so far the origin Expression (child_node) -> NeededCalculations (node_with_needed)

src/Processors/QueryPlan/SortingStep.cpp

@@ -92,7 +92,7 @@ SortingStep::SortingStep(
 void SortingStep::updateInputStream(DataStream input_stream)
 {
     input_streams.clear();
-    input_streams.push_back(std::move(input_stream));
+    input_streams.emplace_back(std::move(input_stream));
 }
 
 void SortingStep::updateOutputStream(Block result_header)

tests/queries/0_stateless/01600_remerge_sort_lowered_memory_bytes_ratio.sql

@@ -10,8 +10,8 @@ set max_block_size=40960;
 --     MergeSortingTransform: Re-merging intermediate ORDER BY data (20 blocks with 819200 rows) to save memory consumption
 --     MergeSortingTransform: Memory usage is lowered from 186.25 MiB to 95.00 MiB
 --     MergeSortingTransform: Re-merging is not useful (memory usage was not lowered by remerge_sort_lowered_memory_bytes_ratio=2.0)
-select repeat(toString(number), 11) v1, repeat(toString(number), 12) v2 from numbers(3e6) order by v1, v2 limit 400e3 format Null; -- { serverError 241 }
-select repeat(toString(number), 11) v1, repeat(toString(number), 12) v2 from numbers(3e6) order by v1, v2 limit 400e3 settings remerge_sort_lowered_memory_bytes_ratio=2. format Null; -- { serverError 241 }
+select number k, repeat(toString(number), 11) v1, repeat(toString(number), 12) v2 from numbers(3e6) order by v1, v2 limit 400e3 format Null; -- { serverError 241 }
+select number k, repeat(toString(number), 11) v1, repeat(toString(number), 12) v2 from numbers(3e6) order by v1, v2 limit 400e3 settings remerge_sort_lowered_memory_bytes_ratio=2. format Null; -- { serverError 241 }
 
 -- remerge_sort_lowered_memory_bytes_ratio 1.9 is good (need at least 1.91/0.98=1.94)
 --     MergeSortingTransform: Re-merging intermediate ORDER BY data (20 blocks with 819200 rows) to save memory consumption

tests/queries/0_stateless/01655_plan_optimizations.reference

@@ -143,17 +143,11 @@ Filter
 2	3
 2	3
 > function calculation should be done after sorting and limit (if possible)
-> the whole Expression node could be moved after Sorting
-Expression
-Limit
-Expression
-Sorting
-Expression
 > Expression should be divided into two subexpressions and only one of them should be moved after Sorting
-Expression
-Limit
-Expression
+Expression (Before ORDER BY [lifted up part])
+FUNCTION sipHash64
 Sorting
-Expression
+Expression (Before ORDER BY)
+FUNCTION plus
 > this query should be executed without throwing an exception
 0

tests/queries/0_stateless/01655_plan_optimizations.sh

@@ -198,14 +198,10 @@ $CLICKHOUSE_CLIENT -q "
     ) where a != 1 settings enable_optimize_predicate_expression = 0"
 
 echo "> function calculation should be done after sorting and limit (if possible)"
-echo "> the whole Expression node could be moved after Sorting"
-$CLICKHOUSE_CLIENT -q "
-    explain select sipHash64(number) from numbers(100) order by number limit 5" |
-    sed 's/ //g' | grep -o "^ *\(Expression\|Limit\|Sorting\)"
 echo "> Expression should be divided into two subexpressions and only one of them should be moved after Sorting"
 $CLICKHOUSE_CLIENT -q "
-    explain select sipHash64(number) from numbers(100) order by number + 1 limit 5" |
-    sed 's/ //g' | grep -o "^ *\(Expression\|Limit\|Sorting\)"
+    explain actions = 1 select number as n, sipHash64(n) from numbers(100) order by number + 1 limit 5" |
+    sed 's/^ *//g' | grep -o "^ *\(Expression (Before ORDER BY.*)\|Sorting\|FUNCTION \w\+\)"
 echo "> this query should be executed without throwing an exception"
 $CLICKHOUSE_CLIENT -q "
     select throwIf(number = 5) from (select * from numbers(10)) order by number limit 1"