hbase-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jean-Daniel Cryans (JIRA)" <j...@apache.org>
Subject [jira] Created: (HBASE-1918) Don't do DNS resolving in .META. scanner for each row
Date Mon, 19 Oct 2009 18:55:59 GMT
Don't do DNS resolving in .META. scanner for each row

                 Key: HBASE-1918
                 URL: https://issues.apache.org/jira/browse/HBASE-1918
             Project: Hadoop HBase
          Issue Type: Improvement
    Affects Versions: 0.20.1, 0.19.3
            Reporter: Jean-Daniel Cryans
            Assignee: Jean-Daniel Cryans
             Fix For: 0.20.2, 0.21.0

While debugging a slow HBase on my new Mac, I found that my issue was that DNS resolving was
taking 10 seconds. Since Java 1.5, many people complained about that and there's even a very
commented issue (http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5092063) that's closed
but still "active". In fact the real issue here is that when you a bad DNS resolving (my router
was acting on me, it's dead now) it waits for 10 seconds or something like that (see previous
link). So I was running PE and my meta scanner was being slower and slower. In fact, everything
was slow, even starting the shell. So using jps I found that we are resolving DNS for each
scanned row in META in checkAssigned here:

if (sa != null && sa.length() > 0) {
  serverName = HServerInfo.getServerName(sa, sc);
HServerInfo storedInfo = null;

HSI.getServerName here creates a new HServerAddress which resolves DNS in its depths and it's
not even necessary, we use it just to split the server IP and port.

This message is automatically generated by JIRA.
You can reply to this email to add a comment to the issue online.

View raw message