[Enhancement] Scale writers for connector sink when writing static partition tables

[mxdzs0612]

Why I'm doing:

What I'm doing:

By default, writers which quantity is equal to sink_dop will be created at the same time, leading to small files when there is little data. This PR scales up writers one by one for static partition tables, which can cope with this problem.

Before:

After:

What type of PR is this:

• [ ] BugFix
• [ ] Feature
• [x] Enhancement
• [ ] Refactor
• [ ] UT
• [ ] Doc
• [ ] Tool

Does this PR entail a change in behavior?

• [ ] Yes, this PR will result in a change in behavior.
• [x] No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• [ ] Interface/UI changes: syntax, type conversion, expression evaluation, display information
• [ ] Parameter changes: default values, similar parameters but with different default values
• [ ] Policy changes: use new policy to replace old one, functionality automatically enabled
• [ ] Feature removed
• [ ] Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• [ ] I have added test cases for my bug fix or my new feature
• [ ] This pr needs user documentation (for new or modified features or behaviors)
  • [ ] I have added documentation for my new feature or new function
• [ ] This is a backport pr

Bugfix cherry-pick branch check:

• [x] I have checked the version labels which the pr will be auto-backported to the target branch
  • [x] 3.2
  • [ ] 3.1
  • [ ] 3.0
  • [ ] 2.5

[DorianZheng]

@mxdzs0612 Nice work! Do you have any performance number before and after applying this PR?

[mxdzs0612]

@mxdzs0612 Nice work! Do you have any performance number before and after applying this PR?

Just a brief test in SF10. there will be less differences in larger scales.

[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[github-actions[bot]]

[FE Incremental Coverage Report]

:white_check_mark: pass : 2 / 2 (100.00%)

file detail

	path	covered_line	new_line	coverage	not_covered_line_detail
:large_blue_circle:	com/starrocks/qe/SessionVariable.java	2	2	100.00%	[]

[github-actions[bot]]

[BE Incremental Coverage Report]

:white_check_mark: pass : 23 / 26 (88.46%)

file detail

	path	covered_line	new_line	coverage	not_covered_line_detail
:large_blue_circle:	be/src/exec/pipeline/exchange/local_exchange.cpp	10	13	76.92%	[363, 364, 368]
:large_blue_circle:	be/src/runtime/iceberg_table_sink.cpp	1	1	100.00%	[]
:large_blue_circle:	be/src/exec/pipeline/pipeline_builder.cpp	6	6	100.00%	[]
:large_blue_circle:	be/src/exec/chunk_buffer_memory_manager.h	1	1	100.00%	[]
:large_blue_circle:	be/src/runtime/hive_table_sink.cpp	1	1	100.00%	[]
:large_blue_circle:	be/src/exec/pipeline/exchange/local_exchange.h	3	3	100.00%	[]
:large_blue_circle:	be/src/runtime/table_function_table_sink.cpp	1	1	100.00%	[]

[mxdzs0612]

@satanson @dirtysalt PTAL, thx~