[ARROW-9683] [Rust][DataFusion] Implement Debug for ExecutionPlan trait

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Component/s: Rust - DataFusion
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/25739
• Assignee: Andrew Lamb
• Reporter: Andrew Lamb
• Created: 10/Aug/20 15:49
• Updated: 11/Jan/23 08:08
• Resolved: 11/Aug/20 14:56

Description

For ARROW-9653, I was trying to debug the execution plan and I would have found it easier if there had been a way to display the execution plan to better understand and isolate the issue. This would also be nice to have as part of EXPLAIN plan functionality in ARROW-9654

In general, for debugging purposes, we would like to be able to dump out an execution plan. To do so in the idiomatic rust way, we should require that `ExecutionPlan` also implement `std::fmt::Debug`

Here is an example plan for "SELECT c1, c2, MIN(c3) FROM aggregate_test_100 GROUP BY c1, c2"

physical plan is HashAggregateExec {
    group_expr: [
        Column {
            name: "c1",
        },
        Column {
            name: "c2",
        },
    ],
    aggr_expr: [
        Min {
            expr: Column {
                name: "c3",
            },
        },
    ],
    input: DataSourceExec {
        schema: Schema {
            fields: [
                Field {
                    name: "c1",
                    data_type: Utf8,
                    nullable: false,
                    dict_id: 0,
                    dict_is_ordered: false,
                },
                Field {
                    name: "c2",
                    data_type: UInt32,
                    nullable: false,
                    dict_id: 0,
                    dict_is_ordered: false,
                },
                Field {
                    name: "c3",
                    data_type: Int8,
                    nullable: false,
                    dict_id: 0,
                    dict_is_ordered: false,
                },
            ],
            metadata: {},
        },
        partitions.len: 1,
    },
    schema: Schema {
        fields: [
            Field {
                name: "c1",
                data_type: Utf8,
                nullable: true,
                dict_id: 0,
                dict_is_ordered: false,
            },
            Field {
                name: "c2",
                data_type: UInt32,
                nullable: true,
                dict_id: 0,
                dict_is_ordered: false,
            },
            Field {
                name: "MIN(c3)",
                data_type: Int64,
                nullable: true,
                dict_id: 0,
                dict_is_ordered: false,
            },
        ],
        metadata: {},
    },
}

Issue Links

• links to: GitHub Pull Request #7925