Implement tree explain for PartialSortExec

[irenjj]

Which issue does this PR close?

• Closes Implement tree explain for PartialSortExec #15064

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[alamb]

Thanks @irenjj -- this looks great. I think we could make it simpler though . Let me know what you think

[alamb]

I recommend we make this simpler -- specifically the common_prefix_length is too detailed for the TreeRender per

datafusion/datafusion/physical-plan/src/display.rs

Lines 48 to 75 in 2458693

	/// TreeRender, displayed in the `tree` explain type.
	///
	/// This format is inspired by DuckDB's explain plans. The information
	/// presented should be "user friendly", and contain only the most relevant
	/// information for understanding a plan. It should NOT contain the same level
	/// of detail information as the [`Self::Default`] format.
	///
	/// In this mode, each line contains a key=value pair.
	/// Everything before the first `=` is treated as the key, and everything after the
	/// first `=` is treated as the value.
	///
	/// For example, if the output of `TreeRender` is this:
	/// ```text
	/// partition_sizes=[1]
	/// partitions=1
	/// ```
	///
	/// It is rendered in the center of a box in the following way:
	///
	/// ```text
	/// ┌───────────────────────────┐
	/// │ DataSourceExec │
	/// │ -------------------- │
	/// │ partition_sizes: [1] │
	/// │ partitions: 1 │
	/// └───────────────────────────┘
	/// ```
	TreeRender,

I also think the TopK / Fetch thing is confusing

What I would recommend is:

01)┌───────────────────────────┐
02)│      PartialSortExec      │
03)│    --------------------   │
07)│           sort:           │
08)│[a@1 ASC NULLS LAST, b@2...│
09)└─────────────┬─────────────┘
10)┌─────────────┴─────────────┐
11)│     StreamingTableExec    │
12)└───────────────────────────┘

And

01)┌───────────────────────────┐
02)│      PartialSortExec      │
03)│    --------------------   │
04)│       fetch=50      │
09)│           sort:           │
10)│[a@1 ASC NULLS LAST, b@2...│
11)└─────────────┬─────────────┘

Here is what duckdb does for refernece:

D create table foo (x int);
D insert into foo values (1);
D explain select * from foo order by x;

┌─────────────────────────────┐
│┌───────────────────────────┐│
││       Physical Plan       ││
│└───────────────────────────┘│
└─────────────────────────────┘
┌───────────────────────────┐
│         PROJECTION        │
│    ────────────────────   │
│__internal_decompress_integ│
│     ral_integer(#0, 1)    │
│                           │
│          ~1 Rows          │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│          ORDER_BY         │
│    ────────────────────   │
│   memory.main.foo.x ASC   │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│         PROJECTION        │
│    ────────────────────   │
│__internal_compress_integra│
│     l_utinyint(#0, 1)     │
│                           │
│          ~1 Rows          │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│         SEQ_SCAN          │
│    ────────────────────   │
│         Table: foo        │
│   Type: Sequential Scan   │
│       Projections: x      │
│                           │
│          ~1 Rows          │
└───────────────────────────┘

[alamb]

Thanks @irenjj

[alamb]

I recommend avoiding the [ and ] if possible

[alamb]

Thanks again @irenjj