feat: add example using postprocessing

crates/proof-of-sql/examples/movies/main.rs

@@ -0,0 +1,112 @@
+
+//! This is a non-interactive example of using Proof of SQL with a movies dataset.
+//! To run this, use `cargo run --release --example movies`.
+//!
+//! NOTE: If this doesn't work because you do not have the appropriate GPU drivers installed,
+//! you can run `cargo run --release --example movies --no-default-features --features="arrow cpu-perf"` instead. It will be slower for proof generation.
+
+use arrow::datatypes::SchemaRef;
+use arrow_csv::{infer_schema_from_files, ReaderBuilder};
+use proof_of_sql::{
+    base::database::{
+        arrow_schema_utility::get_posql_compatible_schema, OwnedTable, OwnedTableTestAccessor,
+        TestAccessor,
+    },
+    proof_primitive::dory::{
+        DynamicDoryCommitment, DynamicDoryEvaluationProof, ProverSetup, PublicParameters,
+        VerifierSetup,
+    },
+    sql::{parse::QueryExpr, postprocessing::apply_postprocessing_steps, proof::QueryProof},
+};
+use rand::{rngs::StdRng, SeedableRng};
+use std::{fs::File, time::Instant};
+
+// We generate the public parameters and the setups used by the prover and verifier for the Dory PCS.
+// The `max_nu` should be set such that the maximum table size is less than `2^(2*max_nu-1)`.
+const DORY_SETUP_MAX_NU: usize = 8;
+// This should be a "nothing-up-my-sleeve" phrase or number.
+const DORY_SEED: [u8; 32] = *b"ebab60d58dee4cc69658939b7c2a582d";
+
+/// # Panics
+/// Will panic if the query does not parse or the proof fails to verify.
+fn prove_and_verify_query(
+    sql: &str,
+    accessor: &OwnedTableTestAccessor<DynamicDoryEvaluationProof>,
+    prover_setup: &ProverSetup,
+    verifier_setup: &VerifierSetup,
+) {
+    // Parse the query:
+    println!("Parsing the query: {sql}...");
+    let now = Instant::now();
+    let query_plan = QueryExpr::<DynamicDoryCommitment>::try_new(
+        sql.parse().unwrap(),
+        "movies".parse().unwrap(),
+        accessor,
+    )
+    .unwrap();
+    println!("Done in {} ms.", now.elapsed().as_secs_f64() * 1000.);
+
+    // Generate the proof and result:
+    print!("Generating proof...");
+    let now = Instant::now();
+    let (proof, provable_result) = QueryProof::<DynamicDoryEvaluationProof>::new(
+        query_plan.proof_expr(),
+        accessor,
+        &prover_setup,
+    );
+    println!("Done in {} ms.", now.elapsed().as_secs_f64() * 1000.);
+
+    // Verify the result with the proof:
+    print!("Verifying proof...");
+    let now = Instant::now();
+    let result = proof
+        .verify(
+            query_plan.proof_expr(),
+            accessor,
+            &provable_result,
+            &verifier_setup,
+        )
+        .unwrap();
+    let result = apply_postprocessing_steps(result.table, query_plan.postprocessing());
+    println!("Verified in {} ms.", now.elapsed().as_secs_f64() * 1000.);
+
+    // Display the result
+    println!("Query Result:");
+    println!("{result:?}");
+}
+
+fn main() {
+    let mut rng = StdRng::from_seed(DORY_SEED);
+    let public_parameters = PublicParameters::rand(DORY_SETUP_MAX_NU, &mut rng);
+    let prover_setup = ProverSetup::from(&public_parameters);
+    let verifier_setup = VerifierSetup::from(&public_parameters);
+
+    let filename = "./crates/proof-of-sql/examples/movies/movies.csv";
+    let inferred_schema =
+        SchemaRef::new(infer_schema_from_files(&[filename.to_string()], b',', None, true).unwrap());
+    let posql_compatible_schema = get_posql_compatible_schema(&inferred_schema);
+
+    let movies_batch = ReaderBuilder::new(posql_compatible_schema)
+        .with_header(true)
+        .build(File::open(filename).unwrap())
+        .unwrap()
+        .next()
+        .unwrap()
+        .unwrap();
+
+    // Load the table into an "Accessor" so that the prover and verifier can access the data/commitments.
+    let mut accessor =
+        OwnedTableTestAccessor::<DynamicDoryEvaluationProof>::new_empty_with_setup(&prover_setup);
+    accessor.add_table(
+        "movies.movies".parse().unwrap(),
+        OwnedTable::try_from(movies_batch).unwrap(),
+        0,
+    );
+
+    // Query 1: Count the total number of movies
+    prove_and_verify_query(
+        "SELECT COUNT(*) AS total_movies FROM movies",
+        &accessor,
+        &prover_setup,
+        &verifier_setup,
+    );