[
https://issues.apache.org/jira/browse/HBASE-9132?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13730173#comment-13730173
]
Dave Latham commented on HBASE-9132:
------------------------------------
Here's a patch for 0.94.
Table descriptor read:
- first check directory modtime against cached entry.
- If directory has not changed, use cached entry.
- Else, check the descriptor file modtime.
- If the descriptor file has not changed, use it (and create a new cached
entry with the updated directory modtime)
- Else, read the new descriptor file.
> Use table dir modtime to avoid scanning table dir to check cached table
> descriptor in 0.94
> ------------------------------------------------------------------------------------------
>
> Key: HBASE-9132
> URL: https://issues.apache.org/jira/browse/HBASE-9132
> Project: HBase
> Issue Type: Improvement
> Reporter: Dave Latham
> Assignee: Dave Latham
> Fix For: 0.94.12
>
> Attachments: HBASE-9132-0.94.patch
>
>
> As described in HBASE-8778, anything that needs to read table descriptors
> (such as region assignments) currently results in a table directory scan
> which is slow on tables with many regions. HBASE-8778 moved the table
> descriptors to a subdir for 0.96+. For 0.94 a smaller change that is safe
> with rolling restarts is to cache the directory modtime and use the cached
> table descriptor if the directory modtime has not changed since a table
> descriptor change always changes the directory.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
