feat: Add functionality for supporting the GPU engine on Polars Cloud

crates/polars-python/Cargo.toml

@@ -11,8 +11,10 @@ description = "Enable running Polars workloads in Python"
 [dependencies]
 polars-core = { workspace = true, features = ["python"] }
 polars-error = { workspace = true }
+polars-expr = { workspace = true }
 polars-io = { workspace = true }
 polars-lazy = { workspace = true, features = ["python"] }
+polars-mem-engine = { workspace = true }
 polars-ops = { workspace = true, features = ["bitwise"] }
 polars-parquet = { workspace = true, optional = true }
 polars-plan = { workspace = true }
@@ -231,7 +233,7 @@ optimizations = [
   "streaming",
 ]
 
-polars_cloud = ["polars/polars_cloud"]
+polars_cloud = ["polars/polars_cloud", "polars/ir_serde"]
 
 # also includes simd
 nightly = ["polars/nightly"]

crates/polars-python/src/cloud.rs

@@ -1,8 +1,17 @@
-use pyo3::prelude::*;
-use pyo3::types::PyBytes;
+use std::io::Cursor;
+
+use polars_core::error::{polars_err, to_compute_err, PolarsResult};
+use polars_expr::state::ExecutionState;
+use polars_mem_engine::create_physical_plan;
+use polars_plan::plans::{AExpr, IRPlan, IR};
+use polars_plan::prelude::{Arena, Node};
+use pyo3::intern;
+use pyo3::prelude::{PyAnyMethods, PyModule, Python, *};
+use pyo3::types::{IntoPyDict, PyBytes};
 
 use crate::error::PyPolarsErr;
-use crate::PyLazyFrame;
+use crate::lazyframe::visit::NodeTraverser;
+use crate::{PyDataFrame, PyLazyFrame};
 
 #[pyfunction]
 pub fn prepare_cloud_plan(lf: PyLazyFrame, py: Python) -> PyResult<PyObject> {
@@ -11,3 +20,76 @@ pub fn prepare_cloud_plan(lf: PyLazyFrame, py: Python) -> PyResult<PyObject> {
 
     Ok(PyBytes::new_bound(py, &bytes).to_object(py))
 }
+
+/// Take a serialized `IRPlan` and execute it on the GPU engine.
+///
+/// This is done as a Python function because the `NodeTraverser` class created for this purpose
+/// must exactly match the one expected by the `cudf_polars` package.
+#[pyfunction]
+pub fn _execute_ir_plan_with_gpu(ir_plan_ser: Vec<u8>, py: Python) -> PyResult<PyDataFrame> {
+    // Deserialize into IRPlan.
+    let reader = Cursor::new(ir_plan_ser);
+    let mut ir_plan = ciborium::from_reader::<IRPlan, _>(reader)
+        .map_err(to_compute_err)
+        .map_err(PyPolarsErr::from)?;
+
+    // Edit for use with GPU engine.
+    gpu_post_opt(
+        py,
+        ir_plan.lp_top,
+        &mut ir_plan.lp_arena,
+        &mut ir_plan.expr_arena,
+    )
+    .map_err(PyPolarsErr::from)?;
+
+    // Convert to physical plan.
+    let mut physical_plan =
+        create_physical_plan(ir_plan.lp_top, &mut ir_plan.lp_arena, &ir_plan.expr_arena)
+            .map_err(PyPolarsErr::from)?;
+
+    // Execute the plan.
+    let mut state = ExecutionState::new();
+    let df = physical_plan
+        .execute(&mut state)
+        .map_err(PyPolarsErr::from)?;
+
+    Ok(df.into())
+}
+
+/// Prepare the IR for execution by the Polars GPU engine.
+fn gpu_post_opt(
+    py: Python,
+    root: Node,
+    lp_arena: &mut Arena<IR>,
+    expr_arena: &mut Arena<AExpr>,
+) -> PolarsResult<()> {
+    // Get cuDF Python function.
+    let cudf = PyModule::import_bound(py, intern!(py, "cudf_polars")).unwrap();
+    let lambda = cudf.getattr(intern!(py, "execute_with_cudf")).unwrap();
+
+    // Define cuDF config.
+    let polars = PyModule::import_bound(py, intern!(py, "polars")).unwrap();
+    let engine = polars.getattr(intern!(py, "GPUEngine")).unwrap();
+    let kwargs = [("raise_on_fail", true)].into_py_dict_bound(py);
+    let engine = engine.call((), Some(&kwargs)).unwrap();
+
+    // Define node traverser.
+    let nt = NodeTraverser::new(root, std::mem::take(lp_arena), std::mem::take(expr_arena));
+
+    // Get a copy of the arenas.
+    let arenas = nt.get_arenas();
+
+    // Pass the node visitor which allows the Python callback to replace parts of the query plan.
+    // Remove "cuda" or specify better once we have multiple post-opt callbacks.
+    let kwargs = [("config", engine)].into_py_dict_bound(py);
+    lambda
+        .call((nt,), Some(&kwargs))
+        .map_err(|e| polars_err!(ComputeError: "'cuda' conversion failed: {}", e))?;
+
+    // Unpack the arena's.
+    // At this point the `nt` is useless.
+    std::mem::swap(lp_arena, &mut *arenas.0.lock().unwrap());
+    std::mem::swap(expr_arena, &mut *arenas.1.lock().unwrap());
+
+    Ok(())
+}

py-polars/src/lib.rs

@@ -377,6 +377,9 @@ fn polars(py: Python, m: &Bound<PyModule>) -> PyResult<()> {
     #[cfg(feature = "polars_cloud")]
     m.add_wrapped(wrap_pyfunction!(cloud::prepare_cloud_plan))
         .unwrap();
+    #[cfg(feature = "polars_cloud")]
+    m.add_wrapped(wrap_pyfunction!(cloud::_execute_ir_plan_with_gpu))
+        .unwrap();
 
     // Build info
     m.add("__version__", env!("CARGO_PKG_VERSION"))?;