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wip on finish sorting

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This commit is contained in:
CurtizJ 2018-10-04 17:55:02 +03:00
parent dd9516a810
commit 8c2060b48a
4 changed files with 63 additions and 50 deletions
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56
dbms/src/DataStreams/MergeSortingBlockInputStream.cpp
View File

@ -319,17 +319,28 @@ FinishMergeSortingBlockInputStream::FinishMergeSortingBlockInputStream(
removeConstantsFromSortDescription(header, description_to_sort);
}
static bool equalKeysAt(const ColumnsWithSortDescriptions & lhs, const ColumnsWithSortDescriptions & rhs, size_t n, size_t m)
{
for (auto it = lhs.begin(), jt = rhs.begin(); it != lhs.end(); ++it, ++jt)
struct Less
{
int res = it->first->compareAt(n, m, *jt->first, it->second.nulls_direction);
if (res != 0)
const ColumnsWithSortDescriptions & left_columns;
const ColumnsWithSortDescriptions & right_columns;
Less(const ColumnsWithSortDescriptions & left_columns_, const ColumnsWithSortDescriptions & right_columns_) :
left_columns(left_columns_), right_columns(right_columns_) {}
bool operator() (size_t a, size_t b) const
{
for (auto it = left_columns.begin(), jt = right_columns.begin(); it != left_columns.end(); ++it, ++jt)
{
int res = it->second.direction * it->first->compareAt(a, b, *jt->first, it->second.nulls_direction);
if (res < 0)
return true;
else if (res > 0)
return false;
}
return true;
return false;
}
};
Block FinishMergeSortingBlockInputStream::readImpl()
{
@ -356,7 +367,7 @@ Block FinishMergeSortingBlockInputStream::readImpl()
{
block = children.back()->read();
/// End of input stream, but we can`t returns immediatly, we need to merge already read blocks.
/// End of input stream, but we can`t return immediatly, we need to merge already read blocks.
/// Check it later, when get end of stream from impl.
if (!block)
{
@ -373,35 +384,36 @@ Block FinishMergeSortingBlockInputStream::readImpl()
if (size == 0)
continue;
auto columns_with_sort_desc = getColumnsWithSortDescription(block, description_sorted);
removeConstantsFromBlock(block);
/// May be new block starts with new key.
/// Find the position of last already read key in current block.
if (!blocks.empty())
{
const Block & last_block = blocks.back();
if (!equalKeysAt(getColumnsWithSortDescription(last_block, description_sorted), columns_with_sort_desc, last_block.rows() - 1, 0))
break;
}
auto last_columns = getColumnsWithSortDescription(last_block, description_sorted);
auto current_columns = getColumnsWithSortDescription(block, description_sorted);
Less less(last_columns, current_columns);
IColumn::Permutation perm(size);
for (size_t i = 0; i < size; ++i)
perm[i] = i;
PartialSortingLess less(columns_with_sort_desc);
/// We need to save tail of block, because next block may starts with the same key as in tail
/// and we should sort these rows in one chunk.
tail_pos = *std::lower_bound(perm.begin(), perm.end(), size - 1, less);
if (tail_pos != 0)
auto it = std::upper_bound(perm.begin(), perm.end(), last_block.rows() - 1, less);
if (it != perm.end())
{
tail_pos = it - perm.begin();
break;
}
}
/// If we reach here, that means that current block has all rows with the same key as tail of a previous block.
/// If we reach here, that means that current block is first in chunk
/// or it all consists of rows with the same key as tail of a previous block.
blocks.push_back(block);
}
/// We need to save tail of block, because next block may starts with the same key as in tail
/// and we should sort these rows in one chunk.
if (block)
{
Block head_block = block.cloneEmpty();
@ -411,7 +423,7 @@ Block FinishMergeSortingBlockInputStream::readImpl()
head_block.getByPosition(i).column = block.getByPosition(i).column->cut(0, tail_pos);
tail_block.getByPosition(i).column = block.getByPosition(i).column->cut(tail_pos, block.rows() - tail_pos);
}
if (head_block.rows())
blocks.push_back(head_block);
}

2
dbms/src/DataStreams/MergeSortingBlockInputStream.h
View File

@ -133,7 +133,7 @@ private:
/** Takes stream already sorted by `x` and finishes sorting it by (`x`, `y`).
* During sorting only blocks with rows equal by `x` saved in RAM.
* During sorting only blocks with rows that equal by `x` saved in RAM.
* */
class FinishMergeSortingBlockInputStream : public IProfilingBlockInputStream
{

21
dbms/src/Interpreters/sortBlock.cpp
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@ -44,6 +44,27 @@ ColumnsWithSortDescriptions getColumnsWithSortDescription(const Block & block, c
}
struct PartialSortingLess
{
const ColumnsWithSortDescriptions & columns;
explicit PartialSortingLess(const ColumnsWithSortDescriptions & columns_) : columns(columns_) {}
bool operator() (size_t a, size_t b) const
{
for (ColumnsWithSortDescriptions::const_iterator it = columns.begin(); it != columns.end(); ++it)
{
int res = it->second.direction * it->first->compareAt(a, b, *it->first, it->second.nulls_direction);
if (res < 0)
return true;
else if (res > 0)
return false;
}
return false;
}
};
struct PartialSortingLessWithCollation
{
const ColumnsWithSortDescriptions & columns;

20
dbms/src/Interpreters/sortBlock.h
View File

@ -31,26 +31,6 @@ bool isAlreadySorted(const Block & block, const SortDescription & description);
using ColumnsWithSortDescriptions = std::vector<std::pair<const IColumn *, SortColumnDescription>>;
struct PartialSortingLess
{
const ColumnsWithSortDescriptions & columns;
explicit PartialSortingLess(const ColumnsWithSortDescriptions & columns_) : columns(columns_) {}
bool operator() (size_t a, size_t b) const
{
for (ColumnsWithSortDescriptions::const_iterator it = columns.begin(); it != columns.end(); ++it)
{
int res = it->second.direction * it->first->compareAt(a, b, *it->first, it->second.nulls_direction);
if (res < 0)
return true;
else if (res > 0)
return false;
}
return false;
}
};
ColumnsWithSortDescriptions getColumnsWithSortDescription(const Block & block, const SortDescription & description);
}