feat: add TableExec (#346)

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In particular `!` is used if and only if at least one breaking change
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# Rationale for this change
`TableExec` is to be the most common source `ProofPlan` when all
`ProofPlan`s become composable. Basically all it does is reading from a
table. I plan to remove table reading functionalities from all other
`ProofPlan`s soon.
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your changes and offer better suggestions for fixes.

 Example:
 Add `NestedLoopJoinExec`.
 Closes #345.

Since we added `HashJoinExec` in #323 it has been possible to do
provable inner joins. However performance is not satisfactory in some
cases. Hence we need to fix the problem by implement
`NestedLoopJoinExec` and speed up the code
 for `HashJoinExec`.
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# What changes are included in this PR?
- add `TableExec`
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- Add `NestedLoopJoinExec`.
- Speed up `HashJoinExec`.
- Route joins to `NestedLoopJoinExec` if the outer input is sufficiently
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# Are these changes tested?
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N/A

crates/proof-of-sql/src/base/map.rs

@@ -22,7 +22,6 @@ macro_rules! indexmap_macro {
 }
 
 /// Create an [`IndexSet`][self::IndexSet] from a list of values
-#[cfg(test)]
 macro_rules! indexset_macro {
     ($($value:expr,)+) => { $crate::base::map::indexset!($($value),+) };
     ($($value:expr),*) => {
@@ -39,5 +38,4 @@ macro_rules! indexset_macro {
 }
 
 pub(crate) use indexmap_macro as indexmap;
-#[cfg(test)]
 pub(crate) use indexset_macro as indexset;

crates/proof-of-sql/src/sql/proof_plans/dyn_proof_plan.rs

@@ -1,4 +1,4 @@
-use super::{EmptyExec, FilterExec, GroupByExec, ProjectionExec};
+use super::{EmptyExec, FilterExec, GroupByExec, ProjectionExec, TableExec};
 use crate::{
     base::{
         database::{Column, ColumnField, ColumnRef, DataAccessor, OwnedTable, TableRef},
@@ -21,6 +21,8 @@ use serde::{Deserialize, Serialize};
 pub enum DynProofPlan {
     /// Source [`ProofPlan`] for (sub)queries without table source such as `SELECT "No table here" as msg;`
     Empty(EmptyExec),
+    /// Source [`ProofPlan`] for (sub)queries with table source such as `SELECT col from tab;`
+    Table(TableExec),
     /// Provable expressions for queries of the form
     /// ```ignore
     ///     SELECT <result_expr1>, ..., <result_exprN> FROM <table>

crates/proof-of-sql/src/sql/proof_plans/mod.rs

@@ -2,6 +2,11 @@
 mod empty_exec;
 pub use empty_exec::EmptyExec;
 
+mod table_exec;
+pub use table_exec::TableExec;
+#[cfg(all(test, feature = "blitzar"))]
+mod table_exec_test;
+
 mod projection_exec;
 pub(crate) use projection_exec::ProjectionExec;
 #[cfg(all(test, feature = "blitzar"))]

crates/proof-of-sql/src/sql/proof_plans/table_exec.rs

@@ -0,0 +1,111 @@
+use crate::{
+    base::{
+        database::{Column, ColumnField, ColumnRef, DataAccessor, OwnedTable, TableRef},
+        map::{indexset, IndexMap, IndexSet},
+        proof::ProofError,
+        scalar::Scalar,
+    },
+    sql::proof::{
+        CountBuilder, FinalRoundBuilder, FirstRoundBuilder, ProofPlan, ProverEvaluate,
+        VerificationBuilder,
+    },
+};
+use alloc::vec::Vec;
+use bumpalo::Bump;
+use core::iter::repeat_with;
+use serde::{Deserialize, Serialize};
+
+/// Source [`ProofPlan`] for (sub)queries with table source such as `SELECT col from tab;`
+/// Inspired by `DataFusion` data source [`ExecutionPlan`]s such as [`ArrowExec`] and [`CsvExec`].
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+pub struct TableExec {
+    /// Table reference
+    pub table_ref: TableRef,
+    /// Schema of the table
+    pub schema: Vec<ColumnField>,
+}
+
+impl TableExec {
+    /// Creates a new [`TableExec`].
+    #[must_use]
+    pub fn new(table_ref: TableRef, schema: Vec<ColumnField>) -> Self {
+        Self { table_ref, schema }
+    }
+
+    /// Returns the entire table.
+    fn get_table<'a, S: Scalar>(&self, accessor: &'a dyn DataAccessor<S>) -> Vec<Column<'a, S>> {
+        self.schema
+            .iter()
+            .map(|field| {
+                accessor.get_column(ColumnRef::new(
+                    self.table_ref,
+                    field.name(),
+                    field.data_type(),
+                ))
+            })
+            .collect()
+    }
+}
+
+impl ProofPlan for TableExec {
+    fn count(&self, builder: &mut CountBuilder) -> Result<(), ProofError> {
+        builder.count_intermediate_mles(self.schema.len());
+        Ok(())
+    }
+
+    #[allow(unused_variables)]
+    fn verifier_evaluate<S: Scalar>(
+        &self,
+        builder: &mut VerificationBuilder<S>,
+        _accessor: &IndexMap<ColumnRef, S>,
+        _result: Option<&OwnedTable<S>>,
+    ) -> Result<Vec<S>, ProofError> {
+        Ok(repeat_with(|| builder.consume_intermediate_mle())
+            .take(self.schema.len())
+            .collect::<Vec<_>>())
+    }
+
+    fn get_column_result_fields(&self) -> Vec<ColumnField> {
+        self.schema.clone()
+    }
+
+    fn get_column_references(&self) -> IndexSet<ColumnRef> {
+        self.schema
+            .iter()
+            .map(|field| ColumnRef::new(self.table_ref, field.name(), field.data_type()))
+            .collect()
+    }
+
+    fn get_table_references(&self) -> IndexSet<TableRef> {
+        indexset! {self.table_ref}
+    }
+}
+
+impl ProverEvaluate for TableExec {
+    #[tracing::instrument(name = "TableExec::result_evaluate", level = "debug", skip_all)]
+    fn result_evaluate<'a, S: Scalar>(
+        &self,
+        _input_length: usize,
+        _alloc: &'a Bump,
+        accessor: &'a dyn DataAccessor<S>,
+    ) -> Vec<Column<'a, S>> {
+        self.get_table(accessor)
+    }
+
+    fn first_round_evaluate(&self, _builder: &mut FirstRoundBuilder) {}
+
+    #[tracing::instrument(name = "TableExec::final_round_evaluate", level = "debug", skip_all)]
+    #[allow(unused_variables)]
+    fn final_round_evaluate<'a, S: Scalar>(
+        &self,
+        builder: &mut FinalRoundBuilder<'a, S>,
+        alloc: &'a Bump,
+        accessor: &'a dyn DataAccessor<S>,
+    ) -> Vec<Column<'a, S>> {
+        let table = self.get_table(accessor);
+        for column in &table {
+            builder.produce_intermediate_mle(column.as_scalar(alloc));
+        }
+        table
+    }
+}

crates/proof-of-sql/src/sql/proof_plans/table_exec_test.rs

@@ -0,0 +1,88 @@
+use super::test_utility::*;
+use crate::{
+    base::database::{
+        owned_table_utility::*, table_utility::*, ColumnField, ColumnType, TableRef,
+        TableTestAccessor,
+    },
+    sql::proof::{exercise_verification, VerifiableQueryResult},
+};
+use blitzar::proof::InnerProductProof;
+use bumpalo::Bump;
+
+#[test]
+fn we_can_create_and_prove_an_empty_table_exec() {
+    let alloc = Bump::new();
+    let table_ref = TableRef::new("namespace.table_name".parse().unwrap());
+    let plan = table_exec(
+        table_ref,
+        vec![ColumnField::new("a".parse().unwrap(), ColumnType::BigInt)],
+    );
+    let accessor = TableTestAccessor::<InnerProductProof>::new_from_table(
+        table_ref,
+        table([borrowed_bigint("a", [0_i64; 0], &alloc)]),
+        0_usize,
+        (),
+    );
+    let verifiable_res = VerifiableQueryResult::new(&plan, &accessor, &());
+    exercise_verification(&verifiable_res, &plan, &accessor, table_ref);
+    let res = verifiable_res.verify(&plan, &accessor, &()).unwrap().table;
+    let expected = owned_table([bigint("a", [0_i64; 0])]);
+    assert_eq!(res, expected);
+}
+
+#[test]
+fn we_can_create_and_prove_a_table_exec() {
+    let alloc = Bump::new();
+    let table_ref = TableRef::new("namespace.table_name".parse().unwrap());
+    let plan = table_exec(
+        table_ref,
+        vec![
+            ColumnField::new("language_rank".parse().unwrap(), ColumnType::BigInt),
+            ColumnField::new("language_name".parse().unwrap(), ColumnType::VarChar),
+            ColumnField::new("space_and_time".parse().unwrap(), ColumnType::VarChar),
+        ],
+    );
+    let accessor = TableTestAccessor::<InnerProductProof>::new_from_table(
+        table_ref,
+        table([
+            borrowed_bigint("language_rank", [0_i64, 1, 2, 3], &alloc),
+            borrowed_varchar(
+                "language_name",
+                ["English", "Español", "Português", "Français"],
+                &alloc,
+            ),
+            borrowed_varchar(
+                "space_and_time",
+                [
+                    "space and time",
+                    "espacio y tiempo",
+                    "espaço e tempo",
+                    "espace et temps",
+                ],
+                &alloc,
+            ),
+        ]),
+        0_usize,
+        (),
+    );
+    let verifiable_res = VerifiableQueryResult::new(&plan, &accessor, &());
+    exercise_verification(&verifiable_res, &plan, &accessor, table_ref);
+    let res = verifiable_res.verify(&plan, &accessor, &()).unwrap().table;
+    let expected = owned_table([
+        bigint("language_rank", [0, 1, 2, 3]),
+        varchar(
+            "language_name",
+            ["English", "Español", "Português", "Français"],
+        ),
+        varchar(
+            "space_and_time",
+            [
+                "space and time",
+                "espacio y tiempo",
+                "espaço e tempo",
+                "espace et temps",
+            ],
+        ),
+    ]);
+    assert_eq!(res, expected);
+}

crates/proof-of-sql/src/sql/proof_plans/test_utility.rs

@@ -1,5 +1,12 @@
-use super::{DynProofPlan, FilterExec, GroupByExec, ProjectionExec};
-use crate::sql::proof_exprs::{AliasedDynProofExpr, ColumnExpr, DynProofExpr, TableExpr};
+use super::{DynProofPlan, FilterExec, GroupByExec, ProjectionExec, TableExec};
+use crate::{
+    base::database::{ColumnField, TableRef},
+    sql::proof_exprs::{AliasedDynProofExpr, ColumnExpr, DynProofExpr, TableExpr},
+};
+
+pub fn table_exec(table_ref: TableRef, schema: Vec<ColumnField>) -> DynProofPlan {
+    DynProofPlan::Table(TableExec::new(table_ref, schema))
+}
 
 pub fn projection(results: Vec<AliasedDynProofExpr>, table: TableExpr) -> DynProofPlan {
     DynProofPlan::Projection(ProjectionExec::new(results, table))