feat: add space example (#292)

# Rationale for this change

More examples in the repo provide better documentation as well as
provide some regression testing on top of other tests.

# What changes are included in this PR?

An example (related to space) of reading tables for a csv file is
provided along with various queries against those tables.

# Are these changes tested?
Yes

.github/workflows/lint-and-test.yml

@@ -112,6 +112,8 @@ jobs:
         run: cargo run --example hello_world --no-default-features --features="rayon test"
       - name: Run hello_world example (Without Blitzar and Without Rayon)
         run: cargo run --example hello_world --no-default-features --features="test"
+      - name: Run space example
+        run: cargo run --example space
       - name: Run posql_db example (With Blitzar)
         run: bash crates/proof-of-sql/examples/posql_db/run_example.sh
       - name: Run posql_db example (Without Blitzar)

crates/proof-of-sql/Cargo.toml

@@ -75,7 +75,8 @@ default = ["arrow", "perf"]
 arrow = ["dep:arrow", "std"]
 blitzar = ["dep:blitzar", "dep:merlin", "std"]
 test = ["dep:rand", "std"]
-perf = ["blitzar", "rayon", "ark-ec/parallel", "ark-poly/parallel", "ark-ff/asm"]
+perf = ["blitzar", "cpu-perf"]
+cpu-perf = ["rayon", "ark-ec/parallel", "ark-poly/parallel", "ark-ff/asm"]
 rayon = ["dep:rayon", "std"]
 std = ["snafu/std"]
 
@@ -90,6 +91,10 @@ required-features = ["test"]
 name = "posql_db"
 required-features = [ "arrow" ]
 
+[[example]]
+name = "space"
+required-features = [ "arrow" ]
+
 [[bench]]
 name = "posql_benches"
 harness = false

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

@@ -0,0 +1,152 @@
+//! This is an non-interactive example of using Proof of SQL with some space related datasets.
+//! To run this, use `cargo run --release --example space`.
+//!
+//! NOTE: If this doesn't work because you do not have the appropriate GPU drivers installed,
+//! you can run `cargo run --release --example space --no-default-features --features="arrow cpu-perf"` instead. It will be slower for proof generation.
+
+// Note: the space_travellers.csv file was obtained from
+// https://www.kaggle.com/datasets/kaushiksinghrawat/humans-to-have-visited-space
+// under the Apache 2.0 license.
+
+use arrow::datatypes::SchemaRef;
+use arrow_csv::{infer_schema_from_files, ReaderBuilder};
+use proof_of_sql::{
+    base::database::{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)`.
+// For a sampling:
+// max_nu = 3 => max table size is 32 rows
+// max_nu = 4 => max table size is 128 rows
+// max_nu = 8 => max table size is 32768 rows
+// max_nu = 10 => max table size is 0.5 million rows
+// max_nu = 15 => max table size is 0.5 billion rows
+// max_nu = 20 => max table size is 0.5 trillion rows
+// Note: we will eventually load these from a file.
+const DORY_SETUP_MAX_NU: usize = 8;
+// This should be a "nothing-up-my-sleeve" phrase or number.
+const DORY_SEED: [u8; 32] = *b"len 32 rng seed - Space and Time";
+
+/// # 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(),
+        "space".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 filenames = [
+        "./crates/proof-of-sql/examples/space/space_travellers.csv",
+        "./crates/proof-of-sql/examples/space/planets.csv",
+    ];
+    let [space_travellers_batch, planets_batch] = filenames.map(|filename| {
+        ReaderBuilder::new(SchemaRef::new(
+            infer_schema_from_files(&[filename.to_string()], b',', None, true).unwrap(),
+        ))
+        .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(
+        "space.travellers".parse().unwrap(),
+        OwnedTable::try_from(space_travellers_batch).unwrap(),
+        0,
+    );
+    accessor.add_table(
+        "space.planets".parse().unwrap(),
+        OwnedTable::try_from(planets_batch).unwrap(),
+        0,
+    );
+
+    prove_and_verify_query(
+        "SELECT COUNT(*) AS total_travellers FROM travellers",
+        &accessor,
+        &prover_setup,
+        &verifier_setup,
+    );
+    prove_and_verify_query(
+        "SELECT Nationality, COUNT(*) AS num_travellers FROM travellers GROUP BY Nationality ORDER BY num_travellers",
+        &accessor,
+        &prover_setup,
+        &verifier_setup,
+    );
+    prove_and_verify_query(
+        "SELECT Flight, COUNT(*) AS num_travellers FROM travellers WHERE Date > timestamp '2000-01-01T00:00:00Z' GROUP BY Flight ORDER BY num_travellers DESC LIMIT 5",
+        &accessor,
+        &prover_setup,
+        &verifier_setup,
+    );
+    prove_and_verify_query(
+        "SELECT name FROM planets WHERE NOT dwarf",
+        &accessor,
+        &prover_setup,
+        &verifier_setup,
+    );
+    prove_and_verify_query(
+        "SELECT name, density FROM planets ORDER BY density DESC LIMIT 3",
+        &accessor,
+        &prover_setup,
+        &verifier_setup,
+    );
+}

crates/proof-of-sql/examples/space/planets.csv

@@ -0,0 +1,14 @@
+Name,Distance,Dwarf,Density
+Mercury,36,FALSE,5400
+Venus,67,FALSE,5200
+Earth,93,FALSE,5500
+Mars,140,FALSE,3900
+Ceres,260,TRUE,2200
+Jupiter,480,FALSE,1300
+Saturn,890,FALSE,700
+Uranus,1800,FALSE,1300
+Neptune,2800,FALSE,1600
+Pluto,3700,TRUE,1900
+Haumea,4000,TRUE,2000
+Makemake,4300,TRUE,2100
+Eris,6300,TRUE,1500