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dbms: Server: feature development. [#METR-15090]

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This commit is contained in:
Alexey Arno 2015-03-27 19:53:01 +03:00
parent 1c9aa586ed
commit 00209e7bbb
1 changed files with 86 additions and 0 deletions
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86
dbms/src/IO/WriteBufferAIO.cpp
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@ -149,6 +149,40 @@ void WriteBufferAIO::nextImpl()
truncation_count = 0;
/*
Представление данных на диске
XXX : данные, которые хотим записать
ZZZ : данные, которые уже на диске или нули, если отсутствуют данные
region_aligned_begin region_aligned_end
: region_begin region_end :
: : : :
: : : :
+---:-----------+---------------+---------------+---------------+--:------------+
| : | | | | : |
| +-----------+---------------+---------------+---------------+--+ |
|ZZZ|XXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XX|ZZZZZZZZZZZZ|
|ZZZ|XXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XX|ZZZZZZZZZZZZ|
| +-----------+---------------+---------------+---------------+--+ |
| | | | | |
+---------------+---------------+---------------+---------------+---------------+
<--------------->
:
:
DEFAULT_AIO_FILE_BLOCK_SIZE
<--><--------------------------------------------------------------><----------->
: : :
: : :
region_left_padding region_size region_right_padding
<------------------------------------------------------------------------------->
:
:
region_aligned_size
*/
/// Регион диска, в который хотим записать данные.
const off_t region_begin = pos_in_file;
const off_t region_end = pos_in_file + flush_buffer.offset();
@ -162,6 +196,32 @@ void WriteBufferAIO::nextImpl()
const off_t region_aligned_end = region_end + region_right_padding;
const size_t region_aligned_size = region_aligned_end - region_aligned_begin;
/*
Представление данных в буфере до обработки
buffer_begin buffer_end
: :
: :
+---------------+---------------+---------------+-------------:-+
| | | | : |
+---------------+---------------+---------------+-------------+ |
|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXX| |
|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXX| |
+---------------+---------------+---------------+-------------+ |
| | | | |
+---------------+---------------+---------------+---------------+
<------------------------------------------------------------->
:
:
buffer_size
<--------------------------------------------------------------->
:
:
buffer_capacity
*/
/// Буфер данных, которые хотим записать на диск.
const Position buffer_begin = flush_buffer.buffer().begin();
Position buffer_end = buffer_begin + region_size;
@ -170,6 +230,32 @@ void WriteBufferAIO::nextImpl()
/// Обработать буфер, чтобы он отражал структуру региона диска.
/*
Представление данных в буфере после обработки
buffer_begin buffer_end memory_page
: : :
: : :
+---:-----------+---------------+---------------+---------------+--:------------+
| | | | | : |
| +-----------+---------------+---------------+---------------+--+ |
|ZZZ|XXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XX|ZZZZZZZZZZZZ|
|ZZZ|XXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XXXXXXXXXXXXXXX|XX|ZZZZZZZZZZZZ|
| +-----------+---------------+---------------+---------------+--+ |
| | | | | |
+---------------+---------------+---------------+---------------+---------------+
<--><--------------------------------------------------------------><----------->
: : :
: : :
region_left_padding region_size region_right_padding
<------------------------------------------------------------------------------->
:
:
region_aligned_size
*/
size_t excess_count = 0;
if (region_left_padding > 0)