GitHub user davies opened a pull request:
https://github.com/apache/spark/pull/14692
decrease the threshold when split expressions
## What changes were proposed in this pull request?
In 2.0, we change the threshold of splitting expressions from 16K to 64K,
which cause very bad performance on wide table, because the generated method
can't be JIT compiled by default (above the limit of 8K bytecode).
This PR will decrease it to 1K, based on the benchmark results for a wide
table with 400 columns of LongType.
## How was this patch tested?
Added benchmark suite.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/davies/spark split_exprs
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/14692.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 #14692
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commit 2ffe46f81723367af3e23c11ee05fe175ba61f69
Author: Davies Liu <[email protected]>
Date: 2016-08-17T21:40:41Z
decrease the threshold when split expressions
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