## What changes were proposed in this pull request?
Added new benchmark which forcibly invokes Jackson parser to check overhead of its creation for short and wide JSON strings. Existing benchmarks do not allow to check that due to an optimisation introduced by #21909 for empty schema pushed down to JSON datasource. The `count()` action passes empty schema as required schema to the datasource, and Jackson parser is not created at all in that case.
Besides of new benchmark I also refactored existing benchmarks:
- Added `numIters` to control number of iteration in each benchmark
- Renamed `JSON per-line parsing` -> `count a short column`, `JSON parsing of wide lines` -> `count a wide column`, and `Count a dataset with 10 columns` -> `Select a subset of 10 columns`.
Closes#22920 from MaxGekk/json-benchmark-follow-up.
Lead-authored-by: Maxim Gekk <max.gekk@gmail.com>
Co-authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
## What changes were proposed in this pull request?
Refactor JSONBenchmark to use main method
use spark-submit:
`bin/spark-submit --class org.apache.spark.sql.execution.datasources.json.JSONBenchmark --jars ./core/target/spark-core_2.11-3.0.0-SNAPSHOT-tests.jar,./sql/catalyst/target/spark-catalyst_2.11-3.0.0-SNAPSHOT-tests.jar ./sql/core/target/spark-sql_2.11-3.0.0-SNAPSHOT-tests.jar`
Generate benchmark result:
`SPARK_GENERATE_BENCHMARK_FILES=1 build/sbt "sql/test:runMain org.apache.spark.sql.execution.datasources.json.JSONBenchmark"`
## How was this patch tested?
manual tests
Closes#22844 from heary-cao/JSONBenchmarks.
Lead-authored-by: caoxuewen <cao.xuewen@zte.com.cn>
Co-authored-by: heary <cao.xuewen@zte.com.cn>
Co-authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: hyukjinkwon <gurwls223@apache.org>
