thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-11-22 15:42:02 +00:00
Code Issues Packages Projects Releases Wiki Activity

dbms: improved performance of system.numbers table [#METR-11434].

Browse Source
This commit is contained in:
Alexey Milovidov 2014-06-04 03:34:44 +04:00
parent 0ee6ba4b67
commit 647ff835c4
1 changed files with 7 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
dbms/src/Storages/StorageSystemNumbers.cpp
View File

@ -30,11 +30,15 @@ Block NumbersBlockInputStream::readImpl()
ColumnUInt64::Container_t & vec = column->getData();
column_with_name_and_type.column = column;
for (size_t i = 0; i < block_size; ++i)
vec[i] = next++;
size_t curr = next; /// Локальная переменная почему-то работает быстрее (>20%), чем член класса.
UInt64 * pos = &vec[0]; /// Это тоже ускоряет код.
UInt64 * end = &vec[block_size];
while (pos < end)
*pos++ = curr++;
next = curr;
res.insert(column_with_name_and_type);
return res;
}