Minor fixups + add a tests

src/Storages/MergeTree/VectorSimilarityCondition.cpp

@@ -40,7 +40,7 @@ void extractReferenceVectorFromLiteral(std::vector<Float64> & reference_vector,
     }
 }
 
-VectorSimilarityCondition::Info::DistanceFunction stringToDistanceFunction(std::string_view distance_function)
+VectorSimilarityCondition::Info::DistanceFunction stringToDistanceFunction(const String & distance_function)
 {
     if (distance_function == "L2Distance")
         return VectorSimilarityCondition::Info::DistanceFunction::L2;
@@ -59,7 +59,7 @@ VectorSimilarityCondition::VectorSimilarityCondition(const SelectQueryInfo & que
     , index_is_useful(checkQueryStructure(query_info))
 {}
 
-bool VectorSimilarityCondition::alwaysUnknownOrTrue(String distance_function) const
+bool VectorSimilarityCondition::alwaysUnknownOrTrue(const String & distance_function) const
 {
     if (!index_is_useful)
         return true; /// query isn't supported

src/Storages/MergeTree/VectorSimilarityCondition.h

@@ -69,7 +69,7 @@ public:
     };
 
     /// Returns false if query can be speeded up by an ANN index, true otherwise.
-    bool alwaysUnknownOrTrue(String distance_function) const;
+    bool alwaysUnknownOrTrue(const String & distance_function) const;
 
     std::vector<Float64> getReferenceVector() const;
     size_t getDimensions() const;
@@ -142,10 +142,6 @@ private:
     /// Traverses the AST of ORDERBY section
     void traverseOrderByAST(const ASTPtr & node, RPN & rpn);
 
-    /// Returns true and stores ANNExpr if the query has valid WHERE section
-    /// TODO NOT implemented, WHERE does not supported.
-    static bool matchRPNWhere(RPN & rpn, Info & info);
-
     /// Returns true and stores ANNExpr if the query has valid ORDERBY section
     static bool matchRPNOrderBy(RPN & rpn, Info & info);
 

tests/queries/0_stateless/02354_vector_search_queries.reference

@@ -41,6 +41,21 @@ Special cases
 6	[1,9.3]	0.005731362878640178
 1	[2,3.2]	0.15200169244542905
 7	[5.5,4.7]	0.3503476876550442
+Expression (Projection)
+  Limit (preliminary LIMIT (without OFFSET))
+    Sorting (Sorting for ORDER BY)
+      Expression (Before ORDER BY)
+        ReadFromMergeTree (default.tab)
+        Indexes:
+          PrimaryKey
+            Condition: true
+            Parts: 1/1
+            Granules: 4/4
+          Skip
+            Name: idx
+            Description: vector_similarity GRANULARITY 2
+            Parts: 1/1
+            Granules: 2/4
 -- Setting "max_limit_for_ann_queries"
 Expression (Projection)
   Limit (preliminary LIMIT (without OFFSET))

tests/queries/0_stateless/02354_vector_search_queries.sql

@@ -63,6 +63,13 @@ FROM tab
 ORDER BY cosineDistance(vec, reference_vec)
 LIMIT 3;
 
+EXPLAIN indexes = 1
+WITH [0.0, 2.0] AS reference_vec
+SELECT id, vec, cosineDistance(vec, reference_vec)
+FROM tab
+ORDER BY cosineDistance(vec, reference_vec)
+LIMIT 3;
+
 SELECT '-- Setting "max_limit_for_ann_queries"';
 EXPLAIN indexes=1
 WITH [0.0, 2.0] as reference_vec