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Use reserve() over resize() for Map

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Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
This commit is contained in:
Azat Khuzhin 2022-01-28 20:02:13 +03:00
parent 9e740eb9d0
commit b511abb72c
2 changed files with 11 additions and 7 deletions
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10
src/Columns/ColumnMap.cpp
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@ -64,8 +64,9 @@ MutableColumnPtr ColumnMap::cloneResized(size_t new_size) const
Field ColumnMap::operator[](size_t n) const
{
auto array = DB::get<Array>((*nested)[n]);
return Map(std::make_move_iterator(array.begin()), std::make_move_iterator(array.end()));
Field res;
get(n, res);
return res;
}
void ColumnMap::get(size_t n, Field & res) const
@ -74,11 +75,12 @@ void ColumnMap::get(size_t n, Field & res) const
size_t offset = offsets[n - 1];
size_t size = offsets[n] - offsets[n - 1];
res = Map(size);
res = Map();
auto & map = DB::get<Map &>(res);
map.reserve(size);
for (size_t i = 0; i < size; ++i)
getNestedData().get(offset + i, map[i]);
map.push_back(getNestedData()[offset + i]);
}
bool ColumnMap::isDefaultAt(size_t n) const

8
src/DataTypes/Serializations/SerializationMap.cpp
View File

@ -53,13 +53,15 @@ void SerializationMap::deserializeBinary(Field & field, ReadBuffer & istr) const
{
size_t size;
readVarUInt(size, istr);
field = Map(size);
for (auto & elem : field.get<Map &>())
field = Map();
Map & map = field.get<Map &>();
map.reserve(size);
for (size_t i = 0; i < size; ++i)
{
Tuple tuple(2);
key->deserializeBinary(tuple[0], istr);
value->deserializeBinary(tuple[1], istr);
elem = std::move(tuple);
map.push_back(std::move(tuple));
}
}