GitHub user lins05 opened a pull request:
https://github.com/apache/spark/pull/16893
[SPARK-19555][SQL] Improve the performance of StringUtils.escapeLikeRegex
method
## What changes were proposed in this pull request?
Copied from [SPARK-19555](https://issues.apache.org/jira/browse/SPARK-19555)
Spark's `StringUtils.escapeLikeRegex()` method is written inefficiently,
performing tons of object allocations due to the use `zip()`, `flatMap()` , and
`mkString`. Instead, I think method should be rewritten in an imperative style
using a Java string builder.
This method can become a performance bottleneck in cases where regex
expressions are used with non-constant-foldable expressions (e.g. the regex
expression comes from the data rather than being part of the query).
## How was this patch tested?
Existing tests.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/lins05/spark
spark-19555-improve-escape-like-regex
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/16893.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 #16893
----
commit bbcdeda98c14705b6de3efab70f2c58bc4539bb9
Author: Shuai Lin <[email protected]>
Date: 2017-02-11T07:46:34Z
[SPARK-19555][SQL] Improve the performance of StringUtils.escapeLikeRegex
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