[
https://issues.apache.org/jira/browse/HBASE-514?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12578541#action_12578541
]
Bryan Duxbury commented on HBASE-514:
-------------------------------------
In looking at the code, I've found one further problem with the way its
original implemented. In HStore#getRowKeyAtOrBefore, if the Memcache returns a
non-null key, then we will automatically use that without looking in the
mapfiles at all. This means that until there is a flush, things are fine.
However, as soon as the memcache flushes once, and there are some writes into
memcache, then the Memcache will return incorrect answers about the closest
row. This actually seems like it could explain difficulties with WREs because
when your HBase gets reasonably large, there will be a .META. region flush, and
then you're hosed for a while.
Instead we need to take the answer the memcache gives us and merge it with the
results we get from the map files. Should be a fairly easy fix.
> table 'does not exist' when it does
> -----------------------------------
>
> Key: HBASE-514
> URL: https://issues.apache.org/jira/browse/HBASE-514
> Project: Hadoop HBase
> Issue Type: Bug
> Components: client
> Affects Versions: 0.16.0
> Reporter: stack
> Attachments: region-v2.patch
>
>
> This one I've seen a few times. In hql, I do show tables and it shows my
> table. I then try to do a select against the table and hql reports table
> does not exist. Digging, whats happening is that the getClosest facility is
> failing to find the first table region in the .META. table. I hacked up a
> region reading tool -- attached (for 0.1 branch) -- and tried it against but
> a copy and the actual instance of the region and it could do the getClosest
> fine. I'm pretty sure I restarted the HRS and when it came up again, the
> master had given it again the .META. and again was failing to find the first
> region in the table (Looked around in server logs and it seemed 'healthy').
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
