fix(asap-physical-operators): seed each CountSketch row independently

crates/asap-aware-mapping/src/empirical_cost.rs

@@ -372,9 +372,10 @@ fn valid_params(algorithm: &SketchAlgorithm, params: &SketchParams) -> bool {
         (SketchAlgorithm::DDSketch, SketchParams::DDSketch { alpha }) => {
             alpha.is_finite() && *alpha > 0.0 && *alpha < 1.0
         }
-        (SketchAlgorithm::Cms, SketchParams::Cms { width, depth })
-        | (SketchAlgorithm::CountSketch, SketchParams::CountSketch { width, depth }) => {
-            *width > 0 && *depth > 0
+        (SketchAlgorithm::Cms, SketchParams::Cms { width, depth }) => *width > 0 && *depth > 0,
+        // A CountSketch reads the median of its rows: the depth must be odd.
+        (SketchAlgorithm::CountSketch, SketchParams::CountSketch { width, depth }) => {
+            *width > 0 && depth % 2 == 1
         }
         (
             SketchAlgorithm::CmsWithHeap,
@@ -383,15 +384,15 @@ fn valid_params(algorithm: &SketchAlgorithm, params: &SketchParams) -> bool {
                 depth,
                 heap_size,
             },
-        )
-        | (
+        ) => *width > 0 && *depth > 0 && *heap_size > 0,
+        (
             SketchAlgorithm::CountSketchWithHeap,
             SketchParams::CountSketchWithHeap {
                 width,
                 depth,
                 heap_size,
             },
-        ) => *width > 0 && *depth > 0 && *heap_size > 0,
+        ) => *width > 0 && depth % 2 == 1 && *heap_size > 0,
         _ => false,
     }
 }
@@ -692,4 +693,37 @@ mod tests {
             Err(EvidenceError::Ambiguous)
         );
     }
+
+    /// A CountSketch reads the median of its rows, so evidence for an even
+    /// depth describes no executable shape.
+    #[test]
+    fn count_sketch_evidence_requires_an_odd_depth() {
+        for (depth, valid) in [(5, true), (4, false)] {
+            assert_eq!(
+                valid_params(
+                    &SketchAlgorithm::CountSketch,
+                    &SketchParams::CountSketch { width: 64, depth }
+                ),
+                valid
+            );
+            assert_eq!(
+                valid_params(
+                    &SketchAlgorithm::CountSketchWithHeap,
+                    &SketchParams::CountSketchWithHeap {
+                        width: 64,
+                        depth,
+                        heap_size: 8
+                    }
+                ),
+                valid
+            );
+        }
+        assert!(valid_params(
+            &SketchAlgorithm::Cms,
+            &SketchParams::Cms {
+                width: 64,
+                depth: 4
+            }
+        ));
+    }
 }

crates/asap-physical-operators/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2021"
 chrono = { version = "0.4.39", default-features = false, features = ["std"] }
 futures = "0.3"
 planner-types = { package = "asap-types", path = "../types" }
-asap_sketchlib = { git = "https://github.com/ProjectASAP/asap_sketchlib", rev = "e6b03142628a3109b6482ebe8512bff7e75f5b35", features = ["experimental"] }
+asap_sketchlib = { git = "https://github.com/ProjectASAP/asap_sketchlib", rev = "9415c5b161237ad238e101ed9166d4dbaace3031", features = ["experimental"] }
 serde = { version = "1", features = ["derive", "rc"] }
 serde_json = "1"
 tracing = "0.1"

crates/asap-physical-operators/src/capability.rs

@@ -61,9 +61,10 @@ pub fn validate_summary_kernel(
                 }
                 (A::Hll, P::Hll { precision }) if (4..=18).contains(precision) => false,
                 (A::Kmv, P::Kmv { k }) if *k >= crate::summary_kernels::kmv::KMV_MIN_K => false,
-                (A::Cms, P::Cms { width, depth })
-                | (A::CountSketch, P::CountSketch { width, depth })
-                    if valid_matrix(*width, *depth) =>
+                (A::Cms, P::Cms { width, depth }) if valid_matrix(*width, *depth) => true,
+                // The median needs an odd row count.
+                (A::CountSketch, P::CountSketch { width, depth })
+                    if valid_matrix(*width, *depth) && depth % 2 == 1 =>
                 {
                     true
                 }