mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-09-22 01:30:51 +00:00
394 lines
14 KiB
C++
394 lines
14 KiB
C++
#pragma once
|
||
|
||
#include <DB/DataStreams/IProfilingBlockInputStream.h>
|
||
#include <DB/Storages/MergeTree/MergeTreeData.h>
|
||
#include <DB/Storages/MergeTree/PKCondition.h>
|
||
#include <DB/Storages/MergeTree/MergeTreeReader.h>
|
||
|
||
|
||
namespace DB
|
||
{
|
||
|
||
/// Для чтения из одного куска. Для чтения сразу из многих, Storage использует сразу много таких объектов.
|
||
class MergeTreeBlockInputStream : public IProfilingBlockInputStream
|
||
{
|
||
public:
|
||
MergeTreeBlockInputStream(const String & path_, /// Путь к куску
|
||
size_t block_size_, Names column_names,
|
||
MergeTreeData & storage_, const MergeTreeData::DataPartPtr & owned_data_part_,
|
||
const MarkRanges & mark_ranges_, bool use_uncompressed_cache_,
|
||
ExpressionActionsPtr prewhere_actions_, String prewhere_column_, bool check_columns,
|
||
size_t min_bytes_to_use_direct_io_, size_t max_read_buffer_size_)
|
||
:
|
||
path(path_), block_size(block_size_),
|
||
storage(storage_), owned_data_part(owned_data_part_),
|
||
part_columns_lock(new Poco::ScopedReadRWLock(owned_data_part->columns_lock)),
|
||
all_mark_ranges(mark_ranges_), remaining_mark_ranges(mark_ranges_),
|
||
use_uncompressed_cache(use_uncompressed_cache_),
|
||
prewhere_actions(prewhere_actions_), prewhere_column(prewhere_column_),
|
||
log(&Logger::get("MergeTreeBlockInputStream")),
|
||
ordered_names{column_names},
|
||
min_bytes_to_use_direct_io(min_bytes_to_use_direct_io_), max_read_buffer_size(max_read_buffer_size_)
|
||
{
|
||
std::reverse(remaining_mark_ranges.begin(), remaining_mark_ranges.end());
|
||
|
||
/// inject columns required for defaults evaluation
|
||
const auto injected_columns = injectRequiredColumns(column_names);
|
||
/// insert injected columns into ordered columns list to avoid exception about different block structures
|
||
ordered_names.insert(std::end(ordered_names), std::begin(injected_columns), std::end(injected_columns));
|
||
|
||
Names pre_column_names;
|
||
|
||
if (prewhere_actions)
|
||
{
|
||
pre_column_names = prewhere_actions->getRequiredColumns();
|
||
|
||
injectRequiredColumns(pre_column_names);
|
||
|
||
if (pre_column_names.empty())
|
||
pre_column_names.push_back(column_names[0]);
|
||
|
||
const NameSet pre_name_set(pre_column_names.begin(), pre_column_names.end());
|
||
/// Если выражение в PREWHERE - не столбец таблицы, не нужно отдавать наружу столбец с ним
|
||
/// (от storage ожидают получить только столбцы таблицы).
|
||
remove_prewhere_column = !pre_name_set.count(prewhere_column);
|
||
|
||
Names post_column_names;
|
||
for (const auto & name : column_names)
|
||
if (!pre_name_set.count(name))
|
||
post_column_names.push_back(name);
|
||
|
||
column_names = post_column_names;
|
||
}
|
||
|
||
/// will be used to distinguish between PREWHERE and WHERE columns when applying filter
|
||
column_name_set = NameSet{column_names.begin(), column_names.end()};
|
||
|
||
if (check_columns)
|
||
{
|
||
/// Под owned_data_part->columns_lock проверим, что все запрошенные столбцы в куске того же типа, что в таблице.
|
||
/// Это может быть не так во время ALTER MODIFY.
|
||
if (!pre_column_names.empty())
|
||
storage.check(owned_data_part->columns, pre_column_names);
|
||
if (!column_names.empty())
|
||
storage.check(owned_data_part->columns, column_names);
|
||
|
||
pre_columns = storage.getColumnsList().addTypes(pre_column_names);
|
||
columns = storage.getColumnsList().addTypes(column_names);
|
||
}
|
||
else
|
||
{
|
||
pre_columns = owned_data_part->columns.addTypes(pre_column_names);
|
||
columns = owned_data_part->columns.addTypes(column_names);
|
||
}
|
||
|
||
/// Оценим общее количество строк - для прогресс-бара.
|
||
size_t total_rows = 0;
|
||
for (const auto & range : all_mark_ranges)
|
||
total_rows += range.end - range.begin;
|
||
total_rows *= storage.index_granularity;
|
||
|
||
LOG_TRACE(log, "Reading " << all_mark_ranges.size() << " ranges from part " << owned_data_part->name
|
||
<< ", approx. " << total_rows
|
||
<< (all_mark_ranges.size() > 1
|
||
? ", up to " + toString((all_mark_ranges.back().end - all_mark_ranges.front().begin) * storage.index_granularity)
|
||
: "")
|
||
<< " rows starting from " << all_mark_ranges.front().begin * storage.index_granularity);
|
||
|
||
setTotalRowsApprox(total_rows);
|
||
}
|
||
|
||
String getName() const override { return "MergeTree"; }
|
||
|
||
String getID() const override
|
||
{
|
||
std::stringstream res;
|
||
res << "MergeTree(" << path << ", columns";
|
||
|
||
for (const NameAndTypePair & column : columns)
|
||
res << ", " << column.name;
|
||
|
||
if (prewhere_actions)
|
||
res << ", prewhere, " << prewhere_actions->getID();
|
||
|
||
res << ", marks";
|
||
|
||
for (size_t i = 0; i < all_mark_ranges.size(); ++i)
|
||
res << ", " << all_mark_ranges[i].begin << ", " << all_mark_ranges[i].end;
|
||
|
||
res << ")";
|
||
return res.str();
|
||
}
|
||
|
||
protected:
|
||
/// Будем вызывать progressImpl самостоятельно.
|
||
void progress(const Progress & value) override {}
|
||
|
||
|
||
/** Если некоторых запрошенных столбцов нет в куске,
|
||
* то выясняем, какие столбцы может быть необходимо дополнительно прочитать,
|
||
* чтобы можно было вычислить DEFAULT выражение для этих столбцов.
|
||
* Добавляет их в columns.
|
||
*/
|
||
NameSet injectRequiredColumns(Names & columns) const
|
||
{
|
||
NameSet required_columns{std::begin(columns), std::end(columns)};
|
||
NameSet injected_columns;
|
||
|
||
for (size_t i = 0; i < columns.size(); ++i)
|
||
{
|
||
const auto & column_name = columns[i];
|
||
|
||
/// column has files and hence does not require evaluation
|
||
if (owned_data_part->hasColumnFiles(column_name))
|
||
continue;
|
||
|
||
const auto default_it = storage.column_defaults.find(column_name);
|
||
/// columns has no explicit default expression
|
||
if (default_it == std::end(storage.column_defaults))
|
||
continue;
|
||
|
||
/// collect identifiers required for evaluation
|
||
IdentifierNameSet identifiers;
|
||
default_it->second.expression->collectIdentifierNames(identifiers);
|
||
|
||
for (const auto & identifier : identifiers)
|
||
{
|
||
if (storage.hasColumn(identifier))
|
||
{
|
||
/// ensure each column is added only once
|
||
if (required_columns.count(identifier) == 0)
|
||
{
|
||
columns.emplace_back(identifier);
|
||
required_columns.emplace(identifier);
|
||
injected_columns.emplace(identifier);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
return injected_columns;
|
||
}
|
||
|
||
|
||
Block readImpl() override
|
||
{
|
||
Block res;
|
||
|
||
if (remaining_mark_ranges.empty())
|
||
return res;
|
||
|
||
if (!reader)
|
||
{
|
||
if (use_uncompressed_cache)
|
||
owned_uncompressed_cache = storage.context.getUncompressedCache();
|
||
|
||
owned_mark_cache = storage.context.getMarkCache();
|
||
|
||
reader.reset(new MergeTreeReader(
|
||
path, owned_data_part, columns, owned_uncompressed_cache.get(), owned_mark_cache.get(), storage,
|
||
all_mark_ranges, min_bytes_to_use_direct_io, max_read_buffer_size));
|
||
|
||
if (prewhere_actions)
|
||
pre_reader.reset(new MergeTreeReader(
|
||
path, owned_data_part, pre_columns, owned_uncompressed_cache.get(), owned_mark_cache.get(), storage,
|
||
all_mark_ranges, min_bytes_to_use_direct_io, max_read_buffer_size));
|
||
}
|
||
|
||
if (prewhere_actions)
|
||
{
|
||
do
|
||
{
|
||
/// Прочитаем полный блок столбцов, нужных для вычисления выражения в PREWHERE.
|
||
size_t space_left = std::max(1LU, block_size / storage.index_granularity);
|
||
MarkRanges ranges_to_read;
|
||
while (!remaining_mark_ranges.empty() && space_left)
|
||
{
|
||
MarkRange & range = remaining_mark_ranges.back();
|
||
|
||
size_t marks_to_read = std::min(range.end - range.begin, space_left);
|
||
pre_reader->readRange(range.begin, range.begin + marks_to_read, res);
|
||
|
||
ranges_to_read.push_back(MarkRange(range.begin, range.begin + marks_to_read));
|
||
space_left -= marks_to_read;
|
||
range.begin += marks_to_read;
|
||
if (range.begin == range.end)
|
||
remaining_mark_ranges.pop_back();
|
||
}
|
||
progressImpl(Progress(res.rowsInFirstColumn(), res.bytes()));
|
||
pre_reader->fillMissingColumns(res, ordered_names);
|
||
|
||
/// Вычислим выражение в PREWHERE.
|
||
prewhere_actions->execute(res);
|
||
|
||
ColumnPtr column = res.getByName(prewhere_column).column;
|
||
if (remove_prewhere_column)
|
||
res.erase(prewhere_column);
|
||
|
||
size_t pre_bytes = res.bytes();
|
||
|
||
/** Если фильтр - константа (например, написано PREWHERE 1),
|
||
* то либо вернём пустой блок, либо вернём блок без изменений.
|
||
*/
|
||
if (ColumnConstUInt8 * column_const = typeid_cast<ColumnConstUInt8 *>(&*column))
|
||
{
|
||
if (!column_const->getData())
|
||
{
|
||
res.clear();
|
||
return res;
|
||
}
|
||
|
||
for (size_t i = 0; i < ranges_to_read.size(); ++i)
|
||
{
|
||
const MarkRange & range = ranges_to_read[i];
|
||
reader->readRange(range.begin, range.end, res);
|
||
}
|
||
|
||
progressImpl(Progress(0, res.bytes() - pre_bytes));
|
||
}
|
||
else if (ColumnUInt8 * column_vec = typeid_cast<ColumnUInt8 *>(&*column))
|
||
{
|
||
size_t index_granularity = storage.index_granularity;
|
||
|
||
const IColumn::Filter & pre_filter = column_vec->getData();
|
||
IColumn::Filter post_filter(pre_filter.size());
|
||
|
||
/// Прочитаем в нужных отрезках остальные столбцы и составим для них свой фильтр.
|
||
size_t pre_filter_pos = 0;
|
||
size_t post_filter_pos = 0;
|
||
for (size_t i = 0; i < ranges_to_read.size(); ++i)
|
||
{
|
||
const MarkRange & range = ranges_to_read[i];
|
||
|
||
size_t begin = range.begin;
|
||
size_t pre_filter_begin_pos = pre_filter_pos;
|
||
for (size_t mark = range.begin; mark <= range.end; ++mark)
|
||
{
|
||
UInt8 nonzero = 0;
|
||
if (mark != range.end)
|
||
{
|
||
size_t limit = std::min(pre_filter.size(), pre_filter_pos + index_granularity);
|
||
for (size_t row = pre_filter_pos; row < limit; ++row)
|
||
nonzero |= pre_filter[row];
|
||
}
|
||
if (!nonzero)
|
||
{
|
||
if (mark > begin)
|
||
{
|
||
memcpy(
|
||
&post_filter[post_filter_pos],
|
||
&pre_filter[pre_filter_begin_pos],
|
||
pre_filter_pos - pre_filter_begin_pos);
|
||
post_filter_pos += pre_filter_pos - pre_filter_begin_pos;
|
||
reader->readRange(begin, mark, res);
|
||
}
|
||
begin = mark + 1;
|
||
pre_filter_begin_pos = std::min(pre_filter_pos + index_granularity, pre_filter.size());
|
||
}
|
||
if (mark < range.end)
|
||
pre_filter_pos = std::min(pre_filter_pos + index_granularity, pre_filter.size());
|
||
}
|
||
}
|
||
|
||
if (!post_filter_pos)
|
||
{
|
||
res.clear();
|
||
continue;
|
||
}
|
||
|
||
progressImpl(Progress(0, res.bytes() - pre_bytes));
|
||
|
||
post_filter.resize(post_filter_pos);
|
||
|
||
/// Отфильтруем столбцы, относящиеся к PREWHERE, используя pre_filter,
|
||
/// остальные столбцы - используя post_filter.
|
||
size_t rows = 0;
|
||
for (size_t i = 0; i < res.columns(); ++i)
|
||
{
|
||
ColumnWithNameAndType & column = res.getByPosition(i);
|
||
if (column.name == prewhere_column && res.columns() > 1)
|
||
continue;
|
||
column.column = column.column->filter(column_name_set.count(column.name) ? post_filter : pre_filter);
|
||
rows = column.column->size();
|
||
}
|
||
|
||
/// Заменим столбец со значением условия из PREWHERE на константу.
|
||
if (!remove_prewhere_column)
|
||
res.getByName(prewhere_column).column = new ColumnConstUInt8(rows, 1);
|
||
}
|
||
else
|
||
throw Exception("Illegal type " + column->getName() + " of column for filter. Must be ColumnUInt8 or ColumnConstUInt8.", ErrorCodes::ILLEGAL_TYPE_OF_COLUMN_FOR_FILTER);
|
||
|
||
reader->fillMissingColumnsAndReorder(res, ordered_names);
|
||
}
|
||
while (!remaining_mark_ranges.empty() && !res && !isCancelled());
|
||
}
|
||
else
|
||
{
|
||
size_t space_left = std::max(1LU, block_size / storage.index_granularity);
|
||
while (!remaining_mark_ranges.empty() && space_left)
|
||
{
|
||
MarkRange & range = remaining_mark_ranges.back();
|
||
|
||
size_t marks_to_read = std::min(range.end - range.begin, space_left);
|
||
reader->readRange(range.begin, range.begin + marks_to_read, res);
|
||
|
||
space_left -= marks_to_read;
|
||
range.begin += marks_to_read;
|
||
if (range.begin == range.end)
|
||
remaining_mark_ranges.pop_back();
|
||
}
|
||
|
||
progressImpl(Progress(res.rowsInFirstColumn(), res.bytes()));
|
||
|
||
reader->fillMissingColumns(res, ordered_names);
|
||
}
|
||
|
||
if (remaining_mark_ranges.empty())
|
||
{
|
||
/** Закрываем файлы (ещё до уничтожения объекта).
|
||
* Чтобы при создании многих источников, но одновременном чтении только из нескольких,
|
||
* буферы не висели в памяти.
|
||
*/
|
||
reader.reset();
|
||
pre_reader.reset();
|
||
part_columns_lock.reset();
|
||
owned_data_part.reset();
|
||
}
|
||
|
||
return res;
|
||
}
|
||
|
||
private:
|
||
const String path;
|
||
size_t block_size;
|
||
NamesAndTypesList columns;
|
||
NameSet column_name_set;
|
||
NamesAndTypesList pre_columns;
|
||
MergeTreeData & storage;
|
||
MergeTreeData::DataPartPtr owned_data_part; /// Кусок не будет удалён, пока им владеет этот объект.
|
||
std::unique_ptr<Poco::ScopedReadRWLock> part_columns_lock; /// Не дадим изменить список столбцов куска, пока мы из него читаем.
|
||
MarkRanges all_mark_ranges; /// В каких диапазонах засечек читать. В порядке возрастания номеров.
|
||
MarkRanges remaining_mark_ranges; /// В каких диапазонах засечек еще не прочли.
|
||
/// В порядке убывания номеров, чтобы можно было выбрасывать из конца.
|
||
bool use_uncompressed_cache;
|
||
std::unique_ptr<MergeTreeReader> reader;
|
||
std::unique_ptr<MergeTreeReader> pre_reader;
|
||
ExpressionActionsPtr prewhere_actions;
|
||
String prewhere_column;
|
||
bool remove_prewhere_column;
|
||
|
||
Logger * log;
|
||
|
||
/// column names in specific order as expected by other stages
|
||
Names ordered_names;
|
||
|
||
size_t min_bytes_to_use_direct_io;
|
||
size_t max_read_buffer_size;
|
||
|
||
UncompressedCachePtr owned_uncompressed_cache;
|
||
MarkCachePtr owned_mark_cache;
|
||
};
|
||
|
||
}
|