GitHub user manishgupta88 opened a pull request:
https://github.com/apache/incubator-carbondata/pull/676
[CARBONDATA-797] Data loss for BigInt datatype if data contains long max
and min values
When data contains long max and min values for a measure column with bigInt
datatype, the delta compression selected is DATA_BYTE which is incorrect. For
selecting the delta compression min value is decremented from max value and
here the min value is negative, so it performs addition operation and goes out
of long range. When a long value goes out of range it starts again from the
long max negative value which results in wrong compression selection.
This leads to data loss and incorrect query results.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/manishgupta88/incubator-carbondata
bigint_data_loss
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-carbondata/pull/676.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 #676
----
commit 4f915d102a5f6186aed5a74cfe23a0a81ea62aee
Author: manishgupta88 <[email protected]>
Date: 2017-03-20T11:43:02Z
When data contains long max and min values for a measure column with bigInt
datatype, the delta compression selected is DATA_BYTE which is incorrect. For
selecting the delta compression min value is decremented from max value and
here the min value is negative, so it performs addition operation and goes out
of long range. When a long value goes out of range it starts again from the
long max negative value which results in wrong compression selection.
This leads to data loss and incorrect query results.
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