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https://issues.apache.org/jira/browse/TRAFODION-3005?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16410129#comment-16410129
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ASF GitHub Bot commented on TRAFODION-3005:
-------------------------------------------
GitHub user DaveBirdsall opened a pull request:
https://github.com/apache/trafodion/pull/1494
[TRAFODION-3005] Fix issues with keys on long columns
This is a follow-on to JIRA TRAFODION-2977 (pull request
https://github.com/apache/trafodion/pull/1473).
I made two changes here.
1. In the previous pull request, I added a check to the CREATE INDEX logic
to make sure the key length is not too long. I put that check too early in the
logic. I have now moved that check to the proper place.
2. It turns out that HBase uses rowIDs + possibly the HBase object name +
some other info to make entries into another HBase structure internally, and
imposes a 32767 key length limit on that. Unfortunately when we exceed the
length limit on that internal structure, the HBase application (Trafodion in
our case) experiences a hang. To avoid these hangs, we will further restrict
maximum key length in Trafodion to 32000. The code change contains a detailed
explanation of how this number was arrived at.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/DaveBirdsall/trafodion Trafodion3005
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/trafodion/pull/1494.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 #1494
----
commit 9c935c529c112afe889a05c5f9aa3498a16a2fac
Author: Dave Birdsall <dbirdsall@...>
Date: 2018-03-22T18:58:38Z
[TRAFODION-3005] Fix issues with keys on long columns
----
> CREATE INDEX on certain long chars fails with Java exceptions
> -------------------------------------------------------------
>
> Key: TRAFODION-3005
> URL: https://issues.apache.org/jira/browse/TRAFODION-3005
> Project: Apache Trafodion
> Issue Type: Bug
> Components: sql-cmp
> Affects Versions: 2.3
> Reporter: David Wayne Birdsall
> Assignee: David Wayne Birdsall
> Priority: Major
>
> The following session illustrates the issue. Creating an index on a
> CHAR(32757) succeeds. Creating an index on a CHAR(32766) fails with a good
> error message (1141). But creating an index on intermediate sizes fails with
> a Java exception, pointing to some bug with near-boundary conditions.
> {{>>drop table if exists mytable;}}{{--- SQL operation complete.}}
> {{>>create table mytable (}}
> {{+>c1 char(32757),}}
> {{+>c2 char(32758),}}
> {{+>c3 char(32765),}}
> {{+>c4 char(32766));}}{{--- SQL operation complete.}}
> {{>>insert into mytable values ('A','A','A','A');}}{{--- 1 row(s) inserted.}}
> {{>>create index idx1 on mytable (c1);}}{{--- SQL operation complete.}}
> {{>>create index idx2 on mytable (c2);}}{{*** ERROR[8448] Unable to access
> Hbase interface. Call to ExpHbaseInterface::addToHFile returned error
> HBASE_ADD_TO_HFILE_ERROR(-713). Cause: java.lang.NegativeArraySizeException}}
> {{org.trafodion.sql.HBulkLoadClient.addToHFile(HBulkLoadClient.java:247).}}
> {{*** ERROR[1081] Loading of index TRAFODION.SCH.IDX2 failed unexpectedly.}}
> {{--- SQL operation failed with errors.}}
> {{>>create index idx3 on mytable (c3);}}
> {{*** ERROR[8448] Unable to access Hbase interface. Call to
> ExpHbaseInterface::addToHFile returned error HBASE_ADD_TO_HFILE_ERROR(-713).
> Cause: java.lang.NegativeArraySizeException}}
> {{org.trafodion.sql.HBulkLoadClient.addToHFile(HBulkLoadClient.java:247).}}
> {{*** ERROR[1081] Loading of index TRAFODION.SCH.IDX3 failed unexpectedly.}}
> {{--- SQL operation failed with errors.}}
> {{>>create index idx4 on mytable (c4);}}
> {{*** ERROR[1141] Key length 32768 exceeds the maximum allowed key length of
> 32767.}}
> {{--- SQL operation failed with errors.}}
> {{>>}}
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