refactor: split relation of planner into one part.

[jackwener]

Which issue does this PR close?

Closes #4392.

FOLLOWUP #4783

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[jackwener]

@alamb @liukun4515 PTAL

[alamb]

Looks great to me @jackwener -- I verified that just code was moved and that no tests were changed

Thank you so much

I think this PR is relatively uncontroversial and is likely to accumulate / cause conflicts, but I plan to wait to merge until @andygrove cuts the release #4776 hopefully later today to avoid introducing last minute churn.

[alamb]

BTW @jackwener another thing I noticed was that the sql planner tests could probably be put into you plan to move the tests into something like datafusion/sql/test/planning.rs or whatnot to make the planner.rs module even smaller

https://github.com/apache/arrow-datafusion/blob/169b5228800f991be913b10ffdfd161e2cbc7baf/datafusion/sql/src/planner.rs#L2021-L2032

[liukun4515]

I will take a look later

[jackwener]

BTW @jackwener another thing I noticed was that the sql planner tests could probably be put into you plan to move the tests into something like datafusion/sql/test/planning.rs or whatnot to make the planner.rs module even smaller

https://github.com/apache/arrow-datafusion/blob/169b5228800f991be913b10ffdfd161e2cbc7baf/datafusion/sql/src/planner.rs#L2021-L2032

Thanks @alamb, I have finished it.

[alamb]

Thanks again @jackwener

I double checked to make sure the tests still run now that they are moved to a different module:

https://github.com/apache/arrow-datafusion/actions/runs/3862329303/jobs/6583883751#step:7:3200

...
     Running tests/integration_test.rs (target/debug/deps/integration_test-02f1355111e126c1)

running 231 tests
test aggregate_with_cube ... ok
test aggregate_with_grouping_sets ... ok
test aggregate_with_rollup_with_grouping ... ok
test aggregate_with_rollup ... ok
test approx_median_window ... ok
test boolean_literal_in_condition_expression ... ok
test cast_from_subquery ... ok
test create_external_table_csv ... ok
test cast_to_invalid_decimal_type ... ok
test create_external_table_custom ... ok
test create_external_table_csv_no_schema ... ok
test create_external_table_parquet ... ok
test create_external_table_parquet_no_schema ... ok
test create_external_table_with_compression_type ... ok
test cte_unbalanced_number_of_columns ... ok
test cross_join_not_to_inner_join ... ok
...

Since this PR has a large potential for conflicts and I think it is uncontroversial as it is mechanical (it moves code around and we can always move it back if that is deired) I am going to merge it and I think we can deal with follow up

Thanks @liukun4515

[ursabot]

Benchmark runs are scheduled for baseline = 8c1fb87 and contender = 3cc607d. 3cc607d is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Skipped ⚠️ Benchmarking of arrow-datafusion-commits is not supported on ec2-t3-xlarge-us-east-2] ec2-t3-xlarge-us-east-2
[Skipped ⚠️ Benchmarking of arrow-datafusion-commits is not supported on test-mac-arm] test-mac-arm
[Skipped ⚠️ Benchmarking of arrow-datafusion-commits is not supported on ursa-i9-9960x] ursa-i9-9960x
[Skipped ⚠️ Benchmarking of arrow-datafusion-commits is not supported on ursa-thinkcentre-m75q] ursa-thinkcentre-m75q
Buildkite builds:
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java