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https://issues.apache.org/jira/browse/DRILL-3826?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15314541#comment-15314541
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Rahul Challapalli commented on DRILL-3826:
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[~sudheeshkatkam] Can you explain
1. How to reproduce this issue without the fix
2. What the fix actually does
> Concurrent Query Submission leads to Channel Closed Exception
> -------------------------------------------------------------
>
> Key: DRILL-3826
> URL: https://issues.apache.org/jira/browse/DRILL-3826
> Project: Apache Drill
> Issue Type: Bug
> Components: Client - JDBC, Execution - RPC
> Affects Versions: 1.1.0, 1.2.0
> Environment: - CentOS release 6.6 (Final)
> - hadoop-2.7.1
> - hbase-1.0.1.1
> - drill-1.1.0
> - jdk-1.8.0_45
> Reporter: Yiyi Hu
> Assignee: Deneche A. Hakim
> Labels: filesystem, hadoop, hbase, jdbc, rpc
> Fix For: 1.7.0
>
> Attachments: jdbc-test-client-drillbit.log, shell-sqlline.log,
> shell-test-drillbit.log
>
>
> Frequently seen CHANNEL CLOSED EXCEPTION while running concurrent quries with
> relatively large LIMIT.
> Here are the details,
> SET UP:
> - Single drillbit running on a single zookeeper node
> - 4G heap size, 8G direct memory
> - Storage plugins: local filesystem, hdfs, hbase
> TEST DATA:
> - A 50,000,000 records json file test.json, with two fields id<Int>,
> title<String> (approximately 3G).
> SHELL TEST:
> - Running 4 drill shells concurrently with query:
> SELECT id, title from dfs.`test.json` LIMIT 5000000.
> - Queries got canceled. Channel closing between client and server were seen
> randomly, as an example shown below:
> {noformat}
> java.lang.RuntimeException: java.sql.SQLException: SYSTEM ERROR:
> ChannelClosedException: Channel closed /192.168.4.201:31010 <-->
> /192.168.4.201:48829.
> Fragment 0:0
> [Error Id: 0bd2b500-155e-46e0-9f26-bd89fea47a25 on TEST-101:31010]
> at sqlline.IncrementalRows.hasNext(IncrementalRows.java:73)
> at
> sqlline.TableOutputFormat$ResizingRowsProvider.next(TableOutputFormat.java:87)
> at sqlline.TableOutputFormat.print(TableOutputFormat.java:118)
> at sqlline.SqlLine.print(SqlLine.java:1583)
> at sqlline.Commands.execute(Commands.java:852)
> at sqlline.Commands.sql(Commands.java:751)
> at sqlline.SqlLine.dispatch(SqlLine.java:738)
> at sqlline.SqlLine.begin(SqlLine.java:612)
> at sqlline.SqlLine.start(SqlLine.java:366)
> at sqlline.SqlLine.main(SqlLine.java:259)
> {noformat}
> JDBC TEST:
> - 6 separate threads running the same query: SELECT id, title from
> dfs.`test.json` LIMIT 10000000, each maintains its own connection. ResultSet,
> statement and connection are closed finally.
> - Throws the same channel closed exception randomly. Log file were enclosed
> for review.
> - Memory usage was monitored, all good.
> CROSS STORAGE PLUGINS:
> - The same issue can be found not only in JSON on a file system (local/hdfs),
> but also in HBASE.
> - The issue was not found in a single thread application.
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