thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-11-11 18:14:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

dbms: lazy opening of files [#CONV-2944].

Browse Source
This commit is contained in:
Alexey Milovidov 2012-06-21 16:16:58 +00:00
parent c9f9913ef5
commit 3482ab7686
1 changed files with 16 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
dbms/src/Storages/StorageLog.cpp
View File

@ -24,8 +24,6 @@ using Poco::SharedPtr;
LogBlockInputStream::LogBlockInputStream(size_t block_size_, const Names & column_names_, StorageLog & storage_, size_t mark_number_, size_t rows_limit_)
: block_size(block_size_), column_names(column_names_), storage(storage_), mark_number(mark_number_), rows_limit(rows_limit_), rows_read(0)
{
for (Names::const_iterator it = column_names.begin(); it != column_names.end(); ++it)
streams.insert(std::make_pair(*it, new Stream(storage.files[*it].data_file.path(), storage.files[*it].marks[mark_number].offset)));
}
@ -33,6 +31,13 @@ Block LogBlockInputStream::readImpl()
{
Block res;
/// Если файлы не открыты, то открываем их.
if (streams.empty())
for (Names::const_iterator it = column_names.begin(); it != column_names.end(); ++it)
streams.insert(std::make_pair(*it, new Stream(
storage.files[*it].data_file.path(),
storage.files[*it].marks[mark_number].offset)));
for (Names::const_iterator it = column_names.begin(); it != column_names.end(); ++it)
{
ColumnWithNameAndType column;
@ -47,6 +52,14 @@ Block LogBlockInputStream::readImpl()
if (res)
rows_read += res.getByPosition(0).column->size();
else
{
/** Закрываем файлы (ещё до уничтожения объекта).
* Чтобы при создании многих источников, но одновременном чтении только из нескольких,
* буферы не висели в памяти.
*/
streams.clear();
}
return res;
}