[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] dhruba borthakur updated HDFS-767: -- Resolution: Fixed Fix Version/s: 0.22.0 Hadoop Flags: [Reviewed] Status: Resolved (was: Patch Available) I just committed this. Thanks Ning! > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Fix For: 0.22.0 > > Attachments: HDFS-767.patch, HDFS-767_2.patch, HDFS-767_3.patch, > HDFS-767_4.txt > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] dhruba borthakur updated HDFS-767: -- Attachment: HDFS-767_4.txt I changed the name of the config to fs.client.retry.window.base to match other DFS config parameters. > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Attachments: HDFS-767.patch, HDFS-767_2.patch, HDFS-767_3.patch, > HDFS-767_4.txt > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ning Zhang updated HDFS-767: Attachment: HDFS-767_3.patch HDFS-767_3.patch contains all the changes suggested by Dhruba. > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Attachments: HDFS-767.patch, HDFS-767_2.patch, HDFS-767_3.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ning Zhang updated HDFS-767: Status: Patch Available (was: In Progress) > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Attachments: HDFS-767.patch, HDFS-767_2.patch, HDFS-767_3.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[
https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
dhruba borthakur updated HDFS-767:
--
Status: Open (was: Patch Available)
Hi Ning, can we get a few more minor issues fixed:
{quote}
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements. See the NOTICE file
+ * Licensed the Apache Software Foundation (ASF) under one
+ * or more contributor license See.
+ * agreements the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
{quote}
The above change change be reverted.
{quote}
prefetchSize =
conf.getLong(DFSConfigKeys.DFS_CLIENT_READ_PREFETCH_SIZE_KEY, prefetchSize);
+ timeWindow =
conf.getInt("dfs.client.baseTimeWindow.waitOn.BlockMissingException", 3000);
{quote}
can we add the new configuration value to DFSConfigKeys?
{quote}
+// See JIRA HDFS-767 for more details.
{quote}
Remove the above comment because this is already captured in the svn revision
history
Thanks a bunch
> Job failure due to BlockMissingException
>
>
> Key: HDFS-767
> URL: https://issues.apache.org/jira/browse/HDFS-767
> Project: Hadoop HDFS
> Issue Type: Improvement
>Reporter: Ning Zhang
>Assignee: Ning Zhang
> Attachments: HDFS-767.patch, HDFS-767_2.patch
>
>
> If a block is request by too many mappers/reducers (say, 3000) at the same
> time, a BlockMissingException is thrown because it exceeds the upper limit (I
> think 256 by default) of number of threads accessing the same block at the
> same time. The DFSClient wil catch that exception and retry 3 times after
> waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients
> will retry at about the same time and a large portion of them get another
> failure. After 3 retries, there are about 256*4 = 1024 clients got the block.
> If the number of clients are more than that, the job will fail.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ning Zhang updated HDFS-767: Status: Patch Available (was: In Progress) > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Attachments: HDFS-767.patch, HDFS-767_2.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ning Zhang updated HDFS-767: Status: In Progress (was: Patch Available) > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Attachments: HDFS-767.patch, HDFS-767_2.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ning Zhang updated HDFS-767: Status: Open (was: Patch Available) > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Attachments: HDFS-767.patch, HDFS-767_2.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ning Zhang updated HDFS-767: Status: Patch Available (was: Open) > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Attachments: HDFS-767.patch, HDFS-767_2.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ning Zhang updated HDFS-767: Attachment: HDFS-767_2.patch I am attaching the second version of the patch. It fixes the javac warning issue. I also did a simple test on nanoTime() on jdk1.6.0_16 on Linux and found it is highly fine grained (consistent with the description that it was implemented using CPU clock cycles). So Random() seed confliction is fairly rare. As mentioined by Dhruba, Random() was used in many places. So we probably don't want to change it in this one place. A separate JIRA is probably the best if it renders iteself as a real problem later. > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Attachments: HDFS-767.patch, HDFS-767_2.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] He Yongqiang updated HDFS-767: -- Status: Patch Available (was: Open) > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang >Assignee: Ning Zhang > Attachments: HDFS-767.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Updated: (HDFS-767) Job failure due to BlockMissingException
[ https://issues.apache.org/jira/browse/HDFS-767?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ning Zhang updated HDFS-767: Attachment: HDFS-767.patch HDFS-767.patch contains the following changes: 1) code change in DFSClient.java to add random backoff discussed in this JIRA. 2) add unit test in TestDFSClientRetries to test effectiveness and performance of different parameters settings. > Job failure due to BlockMissingException > > > Key: HDFS-767 > URL: https://issues.apache.org/jira/browse/HDFS-767 > Project: Hadoop HDFS > Issue Type: Improvement >Reporter: Ning Zhang > Attachments: HDFS-767.patch > > > If a block is request by too many mappers/reducers (say, 3000) at the same > time, a BlockMissingException is thrown because it exceeds the upper limit (I > think 256 by default) of number of threads accessing the same block at the > same time. The DFSClient wil catch that exception and retry 3 times after > waiting for 3 seconds. Since the wait time is a fixed value, a lot of clients > will retry at about the same time and a large portion of them get another > failure. After 3 retries, there are about 256*4 = 1024 clients got the block. > If the number of clients are more than that, the job will fail. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
