### _Why are the changes needed?_
The parallelism of DataGenerator always is `spark.sparkContext.defaultParallelism`, it does not make sense for generating large scale data.
### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible
- [ ] Add screenshots for manual tests if appropriate
- [ ] [Run test](https://kyuubi.readthedocs.io/en/latest/develop_tools/testing.html#running-tests) locally before make a pull request
Closes#1743 from pan3793/tpcds.
Closes#1743
62f7c866 [Cheng Pan] nit
fdcf8329 [Cheng Pan] nit
a52ff489 [Cheng Pan] Fix parallelism of DataGenerator and other enhancements
Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>
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### _Why are the changes needed?_
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Support tpcds benchmark in `dev/kyuubi-tpcds` module.
Add a `README.md` in `dev/kyuubi-tpcds` module to show how to use.
The mian code is from [databricks-spark-sql-perf](https://github.com/databricks/spark-sql-perf)
### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible
- [ ] Add screenshots for manual tests if appropriate
- [x] [Run test](https://kyuubi.readthedocs.io/en/latest/develop_tools/testing.html#running-tests) locally before make a pull request
Closes#1496 from ulysses-you/tpcds-benchmark.
Closes#1496
d4afe2d1 [ulysses-you] comment
54a146ef [ulysses-you] pom
91e71692 [ulysses-you] docs
20eadc49 [ulysses-you] benchmark
Authored-by: ulysses-you <ulyssesyou18@gmail.com>
Signed-off-by: ulysses-you <ulyssesyou@apache.org>
