[
https://issues.apache.org/jira/browse/HBASE-2180?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12838399#action_12838399
]
Erik Rozendaal commented on HBASE-2180:
---------------------------------------
I saw both CLOSE_WAIT and TIME_WAIT. Maybe CLOSE_WAIT was in the majority.
Connections were mostly to the data node.
$ uname -a
Linux inrdb-worker1.ripe.net 2.6.18-164.11.1.el5 #1 SMP Wed Jan 20 07:32:21 EST
2010 x86_64 x86_64 x86_64 GNU/Linux
They do go after a while, since after a few of the "Cannot assign requested
address" exceptions the server starts working again.
Unfortunately I'll be away for the weekend and won't be able to investigate
further. I wonder why so many connections are being opened so quickly that the
server runs out of ports within a few minutes of starting the gets/puts?
> Bad random read performance from synchronizing hfile.fddatainputstream
> ----------------------------------------------------------------------
>
> Key: HBASE-2180
> URL: https://issues.apache.org/jira/browse/HBASE-2180
> Project: Hadoop HBase
> Issue Type: Bug
> Reporter: ryan rawson
> Assignee: stack
> Fix For: 0.20.4, 0.21.0
>
> Attachments: 2180-v2.patch, 2180.patch
>
>
> deep in the HFile read path, there is this code:
> synchronized (in) {
> in.seek(pos);
> ret = in.read(b, off, n);
> }
> this makes it so that only 1 read per file per thread is active. this
> prevents the OS and hardware from being able to do IO scheduling by
> optimizing lots of concurrent reads.
> We need to either use a reentrant API (pread may be partially reentrant
> according to Todd) or use multiple stream objects, 1 per scanner/thread.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
