You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@cassandra.apache.org by "Pavel Yaskevich (JIRA)" <ji...@apache.org> on 2011/04/12 15:12:05 UTC
[jira] [Created] (CASSANDRA-2459) move SSTableScanner to use
SSTableReader.dfile instead of BRAF
move SSTableScanner to use SSTableReader.dfile instead of BRAF
--------------------------------------------------------------
Key: CASSANDRA-2459
URL: https://issues.apache.org/jira/browse/CASSANDRA-2459
Project: Cassandra
Issue Type: Improvement
Components: Core
Reporter: Pavel Yaskevich
Assignee: Pavel Yaskevich
Fix For: 1.0
That can give us the following benefits:
a). don't need to skip a cache because we will be operating on memory mappings
b). better performance (not copying data between kernel and user buffers as effect gained from using memory mapped segments, avoiding time operating on the kernel mode (+ time for switching context and read-ahead pressure) which BRAF involves)
c). less impact on the live-reads
d). less garbage will be created
e). less file descriptors opened
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Updated] (CASSANDRA-2459) move SSTableScanner to use
SSTableReader.dfile instead of BRAF
Posted by "Pavel Yaskevich (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CASSANDRA-2459?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Pavel Yaskevich updated CASSANDRA-2459:
---------------------------------------
Priority: Minor (was: Major)
> move SSTableScanner to use SSTableReader.dfile instead of BRAF
> --------------------------------------------------------------
>
> Key: CASSANDRA-2459
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2459
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Pavel Yaskevich
> Assignee: Pavel Yaskevich
> Priority: Minor
> Fix For: 1.0
>
>
> That can give us the following benefits:
> a). don't need to skip a cache because we will be operating on memory mappings
> b). better performance (not copying data between kernel and user buffers as effect gained from using memory mapped segments, avoiding time operating on the kernel mode (+ time for switching context and read-ahead pressure) which BRAF involves)
> c). less impact on the live-reads
> d). less garbage will be created
> e). less file descriptors opened
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Resolved] (CASSANDRA-2459) move SSTableScanner to use
SSTableReader.dfile instead of BRAF
Posted by "Pavel Yaskevich (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CASSANDRA-2459?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Pavel Yaskevich resolved CASSANDRA-2459.
----------------------------------------
Resolution: Won't Fix
> move SSTableScanner to use SSTableReader.dfile instead of BRAF
> --------------------------------------------------------------
>
> Key: CASSANDRA-2459
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2459
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Pavel Yaskevich
> Assignee: Pavel Yaskevich
> Priority: Minor
> Fix For: 1.0
>
>
> That can give us the following benefits:
> a). don't need to skip a cache because we will be operating on memory mappings
> b). better performance (not copying data between kernel and user buffers as effect gained from using memory mapped segments, avoiding time operating on the kernel mode (+ time for switching context and read-ahead pressure) which BRAF involves)
> c). less impact on the live-reads
> d). less garbage will be created
> e). less file descriptors opened
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (CASSANDRA-2459) move SSTableScanner to use
SSTableReader.dfile instead of BRAF
Posted by "Pavel Yaskevich (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CASSANDRA-2459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13018837#comment-13018837 ]
Pavel Yaskevich commented on CASSANDRA-2459:
--------------------------------------------
Using different sources creates additional I/O pressure where page cache for the same file should be preserved for mmaping and normal I/O, it seems to me that making it a single source with parallel compaction mechanism from CASSANDRA-2191 will lower affect on the live reads during compaction (also CASSANDRA-1902 with migration enabled can guarantee that page cache will be preserved were needed).
> move SSTableScanner to use SSTableReader.dfile instead of BRAF
> --------------------------------------------------------------
>
> Key: CASSANDRA-2459
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2459
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Pavel Yaskevich
> Assignee: Pavel Yaskevich
> Fix For: 1.0
>
>
> That can give us the following benefits:
> a). don't need to skip a cache because we will be operating on memory mappings
> b). better performance (not copying data between kernel and user buffers as effect gained from using memory mapped segments, avoiding time operating on the kernel mode (+ time for switching context and read-ahead pressure) which BRAF involves)
> c). less impact on the live-reads
> d). less garbage will be created
> e). less file descriptors opened
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (CASSANDRA-2459) move SSTableScanner to use
SSTableReader.dfile instead of BRAF
Posted by "Jonathan Ellis (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/CASSANDRA-2459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13018824#comment-13018824 ]
Jonathan Ellis commented on CASSANDRA-2459:
-------------------------------------------
(a) we still need to avoid pushing hot rows out w/ our sequential scan; it seems to me that using the same source as the read stage makes this harder, not easier.
> move SSTableScanner to use SSTableReader.dfile instead of BRAF
> --------------------------------------------------------------
>
> Key: CASSANDRA-2459
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2459
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Pavel Yaskevich
> Assignee: Pavel Yaskevich
> Fix For: 1.0
>
>
> That can give us the following benefits:
> a). don't need to skip a cache because we will be operating on memory mappings
> b). better performance (not copying data between kernel and user buffers as effect gained from using memory mapped segments, avoiding time operating on the kernel mode (+ time for switching context and read-ahead pressure) which BRAF involves)
> c). less impact on the live-reads
> d). less garbage will be created
> e). less file descriptors opened
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira