[GitHub] carbondata pull request #1633: [CARBONDATA-1878] [DataMap] Fix bugs in unsaf...

[asfgit]

Github user asfgit closed the pull request at:

https://github.com/apache/carbondata/pull/1633


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[GitHub] carbondata pull request #1633: [CARBONDATA-1878] [DataMap] Fix bugs in unsaf...

[xuchuanyin]

GitHub user xuchuanyin opened a pull request:

https://github.com/apache/carbondata/pull/1633

[CARBONDATA-1878] [DataMap] Fix bugs in unsafe datamap store

Be sure to do all of the following checklist to help us incorporate 
your contribution quickly and easily:

 - [X] Any interfaces changed?
  `NO`
 - [X] Any backward compatibility impacted?
  `NO`
 - [X] Document update required?
  `NO`
 - [X] Testing done
Please provide details on 
- Whether new unit test cases have been added or why no new tests 
are required?
`ADDED TESTS`
- How it is tested? Please attach test report.
`TEST IN LOCAL MACHINE`
- Is it a performance related change? Please attach the performance 
test report.
`NO, ONLY BUG FIXED`
- Any additional information to help reviewers in testing this 
change.
`NO`
   
 - [X] For large changes, please consider breaking it into sub-tasks under 
an umbrella JIRA. 
`NOT RELATED`

COPY FROM JIRA:
===

# SCENARIO

Recently I have fixed some issues in Carbondata. To perform a full test to 
cover all the code that has been modified by me, I performed some iteration of 
the whole test case. Each iteration is started with different  key 
configurations that will affect the flow in the code.

After I set `enable.offheap.sort=false` (default value is true) in the 
configuration, running tests will always end up with JVM crash error. The error 
messages are shown as below:

```
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x7f346b207ff1, pid=144619, 
tid=0x7f346c2fc700
#
# JRE version: Java(TM) SE Runtime Environment (8.0_111-b14) (build 
1.8.0_111-b14)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.111-b14 mixed mode 
linux-amd64 compressed oops)
# Problematic frame:
# V  [libjvm.so+0xa90ff1]  Unsafe_SetNativeShort+0x51
#
# Failed to write core dump. Core dumps have been disabled. To enable core 
dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /home/xu/ws/carbondata/hs_err_pid144619.log
#
# If you would like to submit a bug report, please visit:
#   http://bugreport.java.com/bugreport/crash.jsp
#

Process finished with exit code 134 (interrupted by signal 6: SIGABRT)
```

# STEPS TOREPRODUCE

The error can be easily reproduced in different ways. Here I will provide a 
simple way to reproduce it:

1. Find the test case `DateDataTypeDirectDictionaryTest`.

2. Add the following code in the method `beforeAll`.
```
CarbonProperties.getInstance()
.addProperty(CarbonCommonConstants.ENABLE_OFFHEAP_SORT, "false")
```

3. Run this test case.

4. You will find the test failed with the above error.

5. Replace the code in Step2 with the following code:
```
CarbonProperties.getInstance()
.addProperty(CarbonCommonConstants.ENABLE_OFFHEAP_SORT, "true")
```

6. Run this test case.

7. The test is success without error.

# ANALYZE & RESOLVE

I have reproduced this error and analyzed the core dump file. The final 
stack message in core dump looks like below:

```
Thread 73303: (state = IN_VM)
 - sun.misc.Unsafe.putShort(long, short) @bci=0 (Interpreted frame)
 - 
org.apache.carbondata.core.indexstore.UnsafeMemoryDMStore.addToUnsafe(org.apache.carbondata.core.indexstore.schema.CarbonRowSchema,
 org.apache.carbondata.core.indexstore.row.DataMapRow, int) @bci=781, line=150 
(Interpreted frame)
 - 
org.apache.carbondata.core.indexstore.UnsafeMemoryDMStore.addIndexRowToUnsafe(org.apache.carbondata.core.indexstore.row.DataMapRow)
 @bci=59, line=99 (Interpreted frame)
 ...
```

After inspecting the code, I found there lies bug in `UnsafeMemoryDMStore 
line=150` while writing length to unsafe memory -- It writes with wrong base 
object.

You can merge this pull request into a Git repository by running:

$ git pull https://github.com/xuchuanyin/carbondata bug_unsafe_dm_store

Alternatively you can review and apply these changes as the patch at:

https://github.com/apache/carbondata/pull/1633.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

This closes #1633


commit 23030ee08de44af5da469678eb7bad009e7b3bd0
Author: xuchuanyin 
Date:   2017-12-08T04:03:09Z

Fix bugs in unsafe datamap store




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