Add learned index (RadixSpline) Rust bindings (#511)

Add end to end tpch benchmarking code
add build script that compiles and links c++ radixspline library
add safe rust module for running radixspline

Note: may need to manually delete radixspline.o and libradixspline.a
from sandbox/qe/RadixSplineLib to force recompilation when changes are
made to the C++ radixspline code.

---------

Co-authored-by: Geoffrey Yu <[email protected]>

.gitignore

@@ -35,3 +35,7 @@ sandbox/qe/.brad_qe_repl_history
 # BRAD UI.
 ui/dist/
 ui/node_modules/
+
+*.tmp
+*.o
+*.a

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "sandbox/qe/RadixSpline"]
+	path = sandbox/qe/RadixSpline
+	url = https://github.com/learnedsystems/RadixSpline

sandbox/qe/Cargo.toml

@@ -2,6 +2,8 @@
 name = "brad_qe"
 version = "0.1.0"
 edition = "2021"
+# NOTE: This currently does not work. (C++ standard library linking error)
+# build = "build.rs"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
@@ -14,11 +16,20 @@ arrow = "50.0.0"
 rustyline = "10.0.0"
 rand = { version = "0.8.5", features = ["small_rng"] }
 csv = "1.3.0"
+cty = "0.2.2"
 
-[[bin]]
-name = "brad_qe_repl"
-path = "src/bin/repl.rs"
+[build-dependencies]
+bindgen = "0.69.4"
+cc = "1.0.96"
 
 [[bin]]
 name = "bench_q3"
 path = "src/bin/bench_q3.rs"
+
+[[bin]]
+name = "brad_qe_repl"
+path = "src/bin/repl.rs"
+
+# [[bin]]
+# name = "test_radixspline"
+# path = "src/bin/test_radixspline.rs"

sandbox/qe/RadixSplineLib/radixspline.cpp

@@ -0,0 +1,27 @@
+#include "radixspline.h"
+
+void* build(const uint64_t* ks, uint64_t size) {
+    RSData* rs = new RSData;
+    rs->keys = std::vector<uint64_t>(size);
+    memcpy(rs->keys.data(), ks, size * sizeof(uint64_t));
+    uint64_t min = rs->keys.front();
+    uint64_t max = rs->keys.back();
+    rs::Builder<uint64_t> rsb(min, max);
+    for (const auto& key : rs->keys) rsb.AddKey(key);
+    rs::RadixSpline<uint64_t> rso = rsb.Finalize();
+    rs->rspline = rso;
+    return (void*)rs;
+}
+
+bool lookup(void* ptr, uint64_t key) {
+    RSData* rs = (RSData*) ptr; 
+    rs::SearchBound bound = rs->rspline.GetSearchBound(key);
+    auto start = begin(rs->keys) + bound.begin, last = begin(rs->keys) + bound.end;
+    auto iter = std::lower_bound(start, last, key);
+    return iter != rs->keys.end() && *iter == key;
+}
+
+void clear(void* ptr) {
+    RSData* rs = (RSData*) ptr;
+    delete rs;
+}

sandbox/qe/RadixSplineLib/radixspline.h

@@ -0,0 +1,18 @@
+#include "../RadixSpline/include/rs/builder.h"
+#include <string.h>
+
+
+struct RSData {
+    std::vector<uint64_t> keys;
+    rs::RadixSpline<uint64_t> rspline;
+};
+
+extern "C" {
+
+    int32_t add(int32_t a, int32_t b);
+    void* build(const uint64_t* ks, uint64_t size);
+
+    bool lookup(void* ptr, uint64_t key);
+
+    void clear(void* ptr);
+}