[KYLIN-2104] loader constraint violation: loader (instance of org/apache/catalina/loader/WebappClassLoader) previously initiated loading for a different type with name "com/google/protobuf/ByteString"

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: v1.5.3
• Environment: MapR 4.1 - Edge node
• Assignee: Unassigned
• Reporter: Richard Calaba
• Created: 18/Oct/16 02:48
• Updated: 18/Oct/16 07:53
• Resolved: 18/Oct/16 07:53

Description

Something very odd is with v.1.5.3 compilation & packaging scripts - it seems that during compilation some req. library is missing or another version is being used and this is not reported as a compilation error which is causing issues later in runtime.

On my MapR 4.1 system - EDGE node which has all necessary access rights for hbase/hive + other packaging tools installed I did this:

1) Followed the https://kylin.apache.org/development/howto_package.html - with one exception - from git I am not clonning latest master branch but specific released Kylin version using tag kylin-1.5.3

2) The bin package is compiled successfully without any errors being reported (I believe test cases are skipped this way - so cannot say test cases run ok)

3) I then installed the successfully compiled Kylin 1.5.3 from sources and run Kylin - all seems OK.

4) I defined and successfully build 2 cubes - no issues during the build process. (Maybe except the fact that Cube size is reported to be 0 Kb on UI having approx. 350 million rows processed during Build -> that looks more like some other bug).

5) If I go to Insights tab in Kylin UI and run any query which should return some data (350 mil. rows processed during build) I am getting an error:

a) 1st time I run any query - ERROR: loader constraint violation: loader (instance of org/apache/catalina/loader/WebappClassLoader) previously initiated loading for a different type with name "com/google/protobuf/ByteString"

b) 2nd and later times - ERROR says only "com/google/protobuf/ByteString"

6) If I STOP the Kylin -> replace the whole binary installation with the officialy released binary package of Kylin 1.5.3 (for HBase 0.98/0.99) - I can run my queries without any issue !!!!

The reason why I am reporting this bug on v 1.5.3 and not on latest released sources 1.5.4.1 is that I have issues to have 1.5.4.1 working - see https://issues.apache.org/jira/browse/KYLIN-2094 - Bin release fails in step #3 of the Build process and 1.5.4.1 compiled from sources doesn't work for me.

All points to some issues with incorrect dependencies being detected during compilation and/or runtime ... maybe related to Google's Protobuffers ...??? Anyone has any idea how to debug this problem ?? Basically it makes both 1.5.3 and 1.5.4.1 not working on my system.

On different system (also MapR 4.1) few months back -> I didn't have those issues -I was able successfully re-compile sources of 1.5.x versions including some additional patches relased for them.

Beacuse no errror is reported during the Kylin compilation & packaging process -> all indicates that there is some strange non-resolved dependency which was OK on my previous MapR system but is different on my current MapR system. Could be anything ...

I will try to attach the compiled binary package here so some guru can have a look and let me know why "successfully" compiled Kylin from sources doesn't run same as the original BIN release. (BTW my compiled archive is several 30 MBs larger than the released binary package ...)

Issue Links

• is related to: KYLIN-2094 Build Step #3 - java.lang.VerifyError: class com.mapr.fs.proto.Common$ServiceData overrides final method getParserForType.()Lcom/google/protobuf/Parser;
• relates to: KYLIN-2094 Build Step #3 - java.lang.VerifyError: class com.mapr.fs.proto.Common$ServiceData overrides final method getParserForType.()Lcom/google/protobuf/Parser;