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fix order of ranges in MergeTreeDataSelectExecutor

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This commit is contained in:
CurtizJ 2020-02-08 00:07:18 +03:00
parent cdcaef9349
commit b9fc9b4569
6 changed files with 31 additions and 24 deletions
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5
dbms/src/Storages/MergeTree/MergeTreeBlockReadUtils.cpp
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@ -73,7 +73,10 @@ MergeTreeReadTask::MergeTreeReadTask(
: data_part{data_part_}, mark_ranges{mark_ranges_}, part_index_in_query{part_index_in_query_},
ordered_names{ordered_names_}, column_name_set{column_name_set_}, columns{columns_}, pre_columns{pre_columns_},
remove_prewhere_column{remove_prewhere_column_}, should_reorder{should_reorder_}, size_predictor{std::move(size_predictor_)}
{}
{
/// We need to save marks in reverse order.
std::reverse(mark_ranges.begin(), mark_ranges.end());
}
MergeTreeReadTask::~MergeTreeReadTask() = default;

5
dbms/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
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@ -718,9 +718,6 @@ Pipes MergeTreeDataSelectExecutor::spreadMarkRangesAmongStreams(
for (size_t i = 0; i < parts.size(); ++i)
{
total_rows += parts[i].getRowsCount();
/// Let the ranges be listed from right to left so that the leftmost range can be dropped using `pop_back()`.
std::reverse(parts[i].ranges.begin(), parts[i].ranges.end());
sum_marks_in_parts[i] = parts[i].getMarksCount();
sum_marks += sum_marks_in_parts[i];
@ -897,6 +894,8 @@ Pipes MergeTreeDataSelectExecutor::spreadMarkRangesAmongStreamsWithOrder(
}
new_ranges.emplace_back(range.begin, range.end);
}
/// Restore left-to-right order.
std::reverse(new_ranges.begin(), new_ranges.end());
}

21
dbms/src/Storages/MergeTree/MergeTreeReadPool.cpp
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@ -28,11 +28,6 @@ MergeTreeReadPool::MergeTreeReadPool(
column_names{column_names_}, do_not_steal_tasks{do_not_steal_tasks_},
predict_block_size_bytes{preferred_block_size_bytes_ > 0}, prewhere_info{prewhere_info_}, parts_ranges{parts_}
{
/// reverse from right-to-left to left-to-right
/// because 'reverse' was done in MergeTreeDataSelectExecutor
for (auto & part_ranges : parts_ranges)
std::reverse(std::begin(part_ranges.ranges), std::end(part_ranges.ranges));
/// parts don't contain duplicate MergeTreeDataPart's.
const auto per_part_sum_marks = fillPerPartInfo(parts_, check_columns_);
fillPerThreadInfo(threads_, sum_marks_, per_part_sum_marks, parts_, min_marks_for_concurrent_read_);
@ -79,10 +74,9 @@ MergeTreeReadTaskPtr MergeTreeReadPool::getTask(const size_t min_marks_to_read,
{
const auto marks_to_get_from_range = marks_in_part;
/** Ranges are in right-to-left order, because 'reverse' was done in MergeTreeDataSelectExecutor
* and that order is supported in 'fillPerThreadInfo'.
*/
/// Ranges are in right-to-left order, because 'reverse' was done in 'fillPerThreadInfo'.
ranges_to_get_from_part = thread_task.ranges;
std::reverse(ranges_to_get_from_part.begin(), ranges_to_get_from_part.end());
marks_in_part -= marks_to_get_from_range;
@ -113,11 +107,7 @@ MergeTreeReadTaskPtr MergeTreeReadPool::getTask(const size_t min_marks_to_read,
marks_in_part -= marks_to_get_from_range;
need_marks -= marks_to_get_from_range;
}
/** Change order to right-to-left, for MergeTreeThreadSelectBlockInputStream to get ranges with .pop_back()
* (order was changed to left-to-right due to .pop_back() above).
*/
std::reverse(std::begin(ranges_to_get_from_part), std::end(ranges_to_get_from_part));
/// Order of ranges was changed to left-to-right due to .pop_back() above.
}
auto curr_task_size_predictor = !per_part_size_predictor[part_idx] ? nullptr
@ -211,7 +201,6 @@ std::vector<size_t> MergeTreeReadPool::fillPerPartInfo(
/// Read marks for every data part.
size_t sum_marks = 0;
/// Ranges are in right-to-left order, due to 'reverse' in MergeTreeDataSelectExecutor.
for (const auto & range : part.ranges)
sum_marks += range.end - range.begin;
@ -251,6 +240,10 @@ void MergeTreeReadPool::fillPerThreadInfo(
{
threads_tasks.resize(threads);
/// Let the ranges be listed from right to left so that the leftmost range can be dropped using `pop_back()`.
for (auto & part : parts)
std::reverse(part.ranges.begin(), part.ranges.end());
const size_t min_marks_per_thread = (sum_marks - 1) / threads + 1;
for (size_t i = 0; i < threads && !parts.empty(); ++i)

7
dbms/src/Storages/MergeTree/MergeTreeSelectProcessor.cpp
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@ -95,11 +95,6 @@ try
task_columns = getReadTaskColumns(storage, data_part, required_columns, prewhere_info, check_columns);
/** @note you could simply swap `reverse` in if and else branches of MergeTreeDataSelectExecutor,
* and remove this reverse. */
MarkRanges remaining_mark_ranges = all_mark_ranges;
std::reverse(remaining_mark_ranges.begin(), remaining_mark_ranges.end());
auto size_predictor = (preferred_block_size_bytes == 0)
? nullptr
: std::make_unique<MergeTreeBlockSizePredictor>(data_part, ordered_names, data_part->storage.getSampleBlock());
@ -109,7 +104,7 @@ try
column_name_set = NameSet{column_names.begin(), column_names.end()};
task = std::make_unique<MergeTreeReadTask>(
data_part, remaining_mark_ranges, part_index_in_query, ordered_names, column_name_set, task_columns.columns,
data_part, all_mark_ranges, part_index_in_query, ordered_names, column_name_set, task_columns.columns,
task_columns.pre_columns, prewhere_info && prewhere_info->remove_prewhere_column,
task_columns.should_reorder, std::move(size_predictor));

1
dbms/tests/queries/0_stateless/01078_merge_tree_read_one_thread.reference Normal file
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@ -0,0 +1 @@
300

16
dbms/tests/queries/0_stateless/01078_merge_tree_read_one_thread.sql Normal file
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@ -0,0 +1,16 @@
drop table if exists t;
create table t (a Int, b Int) engine = MergeTree order by (a, b) settings index_granularity = 400;
insert into t select 0, 0 from numbers(50);
insert into t select 0, 1 from numbers(350);
insert into t select 1, 2 from numbers(400);
insert into t select 2, 2 from numbers(400);
insert into t select 3, 0 from numbers(100);
select sleep(1) format Null; -- sleep a bit to wait possible merges after insert
set max_threads = 1;
optimize table t final;
select sum(a) from t where a in (0, 3) and b = 0;