You are viewing a plain text version of this content. The canonical link for it is here.
Posted to hdfs-dev@hadoop.apache.org by "Todd Lipcon (Created) (JIRA)" <ji...@apache.org> on 2012/02/28 05:58:48 UTC
[jira] [Created] (HDFS-3023) Optimize entries in edits log for
persistBlocks calls
Optimize entries in edits log for persistBlocks calls
-----------------------------------------------------
Key: HDFS-3023
URL: https://issues.apache.org/jira/browse/HDFS-3023
Project: Hadoop HDFS
Issue Type: Improvement
Components: name-node, performance
Affects Versions: HA branch (HDFS-1623), 0.23.2
Reporter: Todd Lipcon
Assignee: Todd Lipcon
One of the performance issues noticed in the HA branch is due to the much larger edit logs, now that we are writing OP_ADD transactions to the edit log on every block allocation. We can condense these calls down in two ways:
1) use variable-length integers for the block list length, size, and genstamp (most of these end up fitting in far less than 8 bytes)
2) use delta-coding for the genstamp and block size for any blocks after the first block (most blocks will be the same size and only slightly higher genstamps)
3) introduce a new OP_UPDATE_BLOCKS transaction that doesn't re-serialize metadata information like lease owner, permissions, etc
4) allow OP_UPDATE_BLOCKS to only re-serialize the blocks that have changed for a given transaction
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Resolved] (HDFS-3023) Optimize entries in edits log for
persistBlocks calls
Posted by "Todd Lipcon (Resolved) (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HDFS-3023?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Todd Lipcon resolved HDFS-3023.
-------------------------------
Resolution: Fixed
Fix Version/s: HA branch (HDFS-1623)
Target Version/s: HA branch (HDFS-1623), 0.24.0 (was: 0.24.0, HA branch (HDFS-1623))
Hadoop Flags: Reviewed
Committed to HA branch.
> Optimize entries in edits log for persistBlocks calls
> -----------------------------------------------------
>
> Key: HDFS-3023
> URL: https://issues.apache.org/jira/browse/HDFS-3023
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: name-node, performance
> Affects Versions: HA branch (HDFS-1623), 0.23.2
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Fix For: HA branch (HDFS-1623)
>
> Attachments: hdfs-3023-HDFS-1623.txt, hdfs-3023.txt
>
>
> One of the performance issues noticed in the HA branch is due to the much larger edit logs, now that we are writing OP_ADD transactions to the edit log on every block allocation. We can condense these calls down in two ways:
> 1) use variable-length integers for the block list length, size, and genstamp (most of these end up fitting in far less than 8 bytes)
> 2) use delta-coding for the genstamp and block size for any blocks after the first block (most blocks will be the same size and only slightly higher genstamps)
> 3) introduce a new OP_UPDATE_BLOCKS transaction that doesn't re-serialize metadata information like lease owner, permissions, etc
> 4) allow OP_UPDATE_BLOCKS to only re-serialize the blocks that have changed for a given transaction
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira