hadoop-hdfs-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Han Xiao (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HDFS-4130) The reading for editlog at NN starting using bkjm is not efficient
Date Tue, 30 Oct 2012 09:02:12 GMT
Han Xiao created HDFS-4130:

             Summary: The reading for editlog at NN starting using bkjm  is not efficient
                 Key: HDFS-4130
                 URL: https://issues.apache.org/jira/browse/HDFS-4130
             Project: Hadoop HDFS
          Issue Type: Improvement
          Components: ha, performance
    Affects Versions: 2.0.2-alpha
            Reporter: Han Xiao

Now, the method of BookKeeperJournalManager.selectInputStreams is written like:

    while (true) {
      EditLogInputStream elis;
      try {
        elis = getInputStream(fromTxId, inProgressOk);
      } catch (IOException e) {
      if (elis == null) {
      if (elis.getLastTxId() == HdfsConstants.INVALID_TXID) {
      fromTxId = elis.getLastTxId() + 1;
EditLogInputstream is got from getInputStream(), which will read the ledgers from zookeeper
in each calling.
This will be a larger cost of times when the the number ledgers becomes large.
The reading of ledgers from zk is not necessary for every calling of getInputStream().

The log of time wasting here is as follows:
2012-10-30 16:44:52,995 INFO org.apache.hadoop.hdfs.server.namenode.NameNode: Caching file
names occuring more than 10 times
2012-10-30 16:49:24,643 INFO hidden.bkjournal.org.apache.bookkeeper.proto.PerChannelBookieClient:
Successfully connected to bookie: /

The stack of the process when blocking between the two lines of log is like:
"main" prio=10 tid=0x000000004011f000 nid=0x39ba in Object.wait() [0x00007fca020fe000]
   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        at java.lang.Object.wait(Object.java:485)
        at hidden.bkjournal.org.apache.zookeeper.ClientCnxn.submitRequest(ClientCnxn.java:1253)
        - locked <0x00000006fb8495a8> (a hidden.bkjournal.org.apache.zookeeper.ClientCnxn$Packet)
        at hidden.bkjournal.org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1129)
        at org.apache.hadoop.contrib.bkjournal.utils.RetryableZookeeper.getData(RetryableZookeeper.java:501)
        at hidden.bkjournal.org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1160)
        at org.apache.hadoop.contrib.bkjournal.EditLogLedgerMetadata.read(EditLogLedgerMetadata.java:113)
        at org.apache.hadoop.contrib.bkjournal.BookKeeperJournalManager.getLedgerList(BookKeeperJournalManager.java:725)
        at org.apache.hadoop.contrib.bkjournal.BookKeeperJournalManager.getInputStream(BookKeeperJournalManager.java:442)
        at org.apache.hadoop.contrib.bkjournal.BookKeeperJournalManager.selectInputStreams(BookKeeperJournalManager.java:480)
betweent different time, the diff of stack is:
diff stack stack2
< 2012-10-30 16:44:53
> 2012-10-30 16:46:17
<       - locked <0x00000006fb8495a8> (a hidden.bkjournal.org.apache.zookeeper.ClientCnxn$Packet)
>       - locked <0x00000006fae58468> (a hidden.bkjournal.org.apache.zookeeper.ClientCnxn$Packet)

In our environment, the waiting time could even reach to tens of minutes.

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

View raw message