deltalake-core 0.32.0

Native Delta Lake implementation in Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151

//! Logical Operations for DataFusion

use std::collections::HashSet;
use std::sync::Arc;

use arrow_schema::Field;
use datafusion::common::{Column, Result};
use datafusion::logical_expr::{
    Extension, LogicalPlan, LogicalPlanBuilder, UserDefinedLogicalNodeCore,
};
use datafusion::prelude::{Expr, col};
use itertools::Itertools;

use crate::delta_datafusion::data_validation::DataValidation;

pub(crate) trait LogicalPlanBuilderExt: Sized {
    fn with_column(self, name: &str, expr: Expr) -> Result<Self>;
    fn drop_columns(self, cols: impl IntoIterator<Item = impl ColumnReference>) -> Result<Self>;
    /// Validate all data produced by the plan coforms to the passed predicates.
    fn validate(self, validations: impl IntoIterator<Item = Expr>) -> Result<Self>;
}

pub(crate) trait ColumnReference: Sized {
    fn col_name(&self) -> &str;
}

impl ColumnReference for &str {
    fn col_name(&self) -> &str {
        self
    }
}

impl ColumnReference for Field {
    fn col_name(&self) -> &str {
        self.name().as_str()
    }
}

impl<T: ColumnReference> ColumnReference for Arc<T> {
    fn col_name(&self) -> &str {
        T::col_name(self)
    }
}

impl LogicalPlanBuilderExt for LogicalPlanBuilder {
    fn with_column(self, name: &str, expr: Expr) -> Result<Self> {
        let mut projection = self
            .schema()
            .iter()
            .map(|(_, f)| col(Column::from_name(f.col_name())))
            .collect_vec();
        projection.push(expr.alias(name));
        self.project(projection)
    }

    fn drop_columns(self, cols: impl IntoIterator<Item = impl ColumnReference>) -> Result<Self> {
        let away_names = cols
            .into_iter()
            .map(|c| c.col_name().to_string())
            .collect::<HashSet<_>>();
        let projection = self
            .schema()
            .iter()
            .filter(|(_, f)| !away_names.contains(f.name()))
            .map(|(_, f)| col(Column::from_name(f.col_name())))
            .collect_vec();
        self.project(projection)
    }

    fn validate(self, validations: impl IntoIterator<Item = Expr>) -> Result<Self> {
        let plan = LogicalPlan::Extension(Extension {
            node: DataValidation::try_new(self.build()?, validations)?,
        });
        Ok(LogicalPlanBuilder::new(plan))
    }
}

pub(crate) trait LogicalPlanExt: Sized {
    fn into_builder(self) -> LogicalPlanBuilder;
}

impl LogicalPlanExt for LogicalPlan {
    fn into_builder(self) -> LogicalPlanBuilder {
        LogicalPlanBuilder::new(self)
    }
}

impl LogicalPlanExt for Arc<LogicalPlan> {
    fn into_builder(self) -> LogicalPlanBuilder {
        LogicalPlanBuilder::new_from_arc(self)
    }
}

// Metric Observer is used to update DataFusion metrics from a record batch.
// See MetricObserverExec for the physical implementation

#[derive(Debug, Hash, Eq, PartialEq, PartialOrd)]
pub(crate) struct MetricObserver {
    // id is preserved during conversion to physical node
    pub id: String,
    pub input: LogicalPlan,
    pub enable_pushdown: bool,
}

impl UserDefinedLogicalNodeCore for MetricObserver {
    // Predicate push down is not supported for this node. Try to limit usage
    // near the end of plan.
    fn name(&self) -> &str {
        "MetricObserver"
    }

    fn inputs(&self) -> Vec<&datafusion::logical_expr::LogicalPlan> {
        vec![&self.input]
    }

    fn schema(&self) -> &datafusion::common::DFSchemaRef {
        self.input.schema()
    }

    fn expressions(&self) -> Vec<datafusion::logical_expr::Expr> {
        vec![]
    }

    fn prevent_predicate_push_down_columns(&self) -> HashSet<String> {
        if self.enable_pushdown {
            HashSet::new()
        } else {
            self.schema()
                .fields()
                .iter()
                .map(|f| f.name().clone())
                .collect()
        }
    }

    fn fmt_for_explain(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(f, "MetricObserver id={}", self.id)
    }

    fn with_exprs_and_inputs(
        &self,
        _exprs: Vec<datafusion::logical_expr::Expr>,
        inputs: Vec<datafusion::logical_expr::LogicalPlan>,
    ) -> datafusion::common::Result<Self> {
        Ok(MetricObserver {
            id: self.id.clone(),
            input: inputs[0].clone(),
            enable_pushdown: self.enable_pushdown,
        })
    }
}