thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-11-25 00:52:02 +00:00
Code Issues Packages Projects Releases Wiki Activity

limit

Browse Source
This commit is contained in:
nikitamikhaylov 2020-09-08 18:54:30 +03:00
parent 8793281e3e
commit c4f0465a7c
1 changed files with 22 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
src/Columns/ColumnNullable.cpp
View File

@ -334,8 +334,7 @@ void ColumnNullable::updatePermutation(bool reverse, size_t limit, int null_dire
if (equal_ranges.empty())
return;
if (limit >= equal_ranges.back().second || limit >= size())
limit = 0;
std::cout << "limit " << limit << std::endl;
/// We will sort nested columns into `new_ranges` and call updatePermutation in next columns with `null_ranges`.
EqualRanges new_ranges, null_ranges;
@ -347,19 +346,22 @@ void ColumnNullable::updatePermutation(bool reverse, size_t limit, int null_dire
/// Shift all NULL values to the end.
for (const auto & [first, last] : equal_ranges)
{
/// Current interval is righter than limit.
if (first > limit)
break;
/// Consider a half interval [first, last)
size_t read_idx = first;
size_t write_idx = first;
size_t end_idx = last;
if (!limit)
limit = end_idx - read_idx;
else
limit = std::min(end_idx - read_idx, limit);
size_t current_limit = end_idx;
if (limit && limit >= read_idx && limit <= end_idx)
current_limit = limit;
/// We simply check the limit not to do extra work.
/// Since interval begins from `first`, not from zero, we add `first` to the right side of the inequality.
while (read_idx < first + limit && !isNullAt(res[read_idx]))
while (read_idx < current_limit && !isNullAt(res[read_idx]))
{
++read_idx;
++write_idx;
@ -377,7 +379,7 @@ void ColumnNullable::updatePermutation(bool reverse, size_t limit, int null_dire
/// Relative order of NULL elements could be changed,
/// but relative order of non-NULLs is preserved.
while (read_idx < end_idx && write_idx < first + limit)
while (read_idx < end_idx && write_idx < current_limit)
{
if (!isNullAt(res[read_idx]))
{
@ -391,7 +393,6 @@ void ColumnNullable::updatePermutation(bool reverse, size_t limit, int null_dire
if (first != write_idx)
new_ranges.emplace_back(first, write_idx);
/// We have a range [write_idx, list) of NULL values
if (write_idx != last)
null_ranges.emplace_back(write_idx, last);
@ -399,9 +400,12 @@ void ColumnNullable::updatePermutation(bool reverse, size_t limit, int null_dire
}
else
{
/// Shift all NULL values to the beginning.
for (const auto & [first, last] : equal_ranges)
{
/// Shift all NULL values to the beginning.
/// Current interval is righter than limit.
if (first > limit)
break;
ssize_t read_idx = last - 1;
ssize_t write_idx = last - 1;
@ -429,13 +433,20 @@ void ColumnNullable::updatePermutation(bool reverse, size_t limit, int null_dire
if (write_idx != static_cast<ssize_t>(last))
new_ranges.emplace_back(write_idx + 1, last);
/// We have a range [first, write_idx+1) of NULL values
if (static_cast<ssize_t>(first) != write_idx)
null_ranges.emplace_back(first, write_idx + 1);
}
}
std::cout << "New Ranges " << std::endl;
for (auto [first, last] : new_ranges )
std::cout << "first " << first << " last " << last << std::endl;
std::cout << "Null Ranges " << std::endl;
for (auto [first, last] : null_ranges)
std::cout << "first " << first << " last " << last << std::endl;
getNestedColumn().updatePermutation(reverse, 0, null_direction_hint, res, new_ranges);
equal_ranges = std::move(new_ranges);