thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-11-24 00:22:29 +00:00
Code Issues Packages Projects Releases Wiki Activity

Added optimized case

Browse Source
This commit is contained in:
Alexey Milovidov 2019-08-23 07:25:32 +03:00
parent 341e2e4587
commit 6685365ab8
1 changed files with 68 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
dbms/src/Functions/neighbor.cpp
View File

@ -107,21 +107,79 @@ public:
if (default_is_constant)
default_column_casted = assert_cast<const ColumnConst &>(*default_column_casted).getDataColumnPtr();
auto column = result_type->createColumn();
for (size_t row = 0; row < input_rows_count; ++row)
if (offset_is_constant)
{
Int64 src_idx = row + offset_column->getInt(offset_is_constant ? 0 : row);
/// Optimization for the case when we can copy many values at once.
if (src_idx >= 0 && src_idx < Int64(input_rows_count))
column->insertFrom(*source_column_casted, source_is_constant ? 0 : src_idx);
else if (has_defaults)
column->insertFrom(*default_column_casted, default_is_constant ? 0 : row);
Int64 offset = offset_column->getInt(0);
auto result_column = result_type->createColumn();
auto insert_range_from = [&](bool is_const, const ColumnPtr & src, Int64 begin, Int64 size)
{
/// Saturation of bounds.
if (begin < 0)
{
size += begin;
begin = 0;
}
if (size <= 0)
return;
if (size > Int64(input_rows_count))
size = input_rows_count;
if (!src)
{
for (Int64 i = 0; i < size; ++i)
result_column->insertDefault();
}
else if (is_const)
{
for (Int64 i = 0; i < size; ++i)
result_column->insertFrom(*src, 0);
}
else
{
result_column->insertRangeFrom(*src, begin, size);
}
};
if (offset == 0)
{
/// Degenerate case, just copy source column as is.
block.getByPosition(result).column = source_column_casted; /// TODO
}
else if (offset > 0)
{
insert_range_from(source_is_constant, source_column_casted, offset, Int64(input_rows_count) - offset);
insert_range_from(default_is_constant, default_column_casted, Int64(input_rows_count) - offset, offset);
block.getByPosition(result).column = std::move(result_column);
}
else
column->insertDefault();
{
insert_range_from(default_is_constant, default_column_casted, 0, -offset);
insert_range_from(source_is_constant, source_column_casted, 0, Int64(input_rows_count) + offset);
block.getByPosition(result).column = std::move(result_column);
}
}
else
{
auto result_column = result_type->createColumn();
block.getByPosition(result).column = std::move(column);
for (size_t row = 0; row < input_rows_count; ++row)
{
Int64 src_idx = row + offset_column->getInt(offset_is_constant ? 0 : row);
if (src_idx >= 0 && src_idx < Int64(input_rows_count))
result_column->insertFrom(*source_column_casted, source_is_constant ? 0 : src_idx);
else if (has_defaults)
result_column->insertFrom(*default_column_casted, default_is_constant ? 0 : row);
else
result_column->insertDefault();
}
block.getByPosition(result).column = std::move(result_column);
}
}
private: