cleanup: one Item_func_vec_distance class, not three

prepare for MDEV-35450 VEC_DISTANCE auto-detection

sql/item_create.cc

@@ -6258,7 +6258,8 @@ class Create_func_vec_distance_euclidean: public Create_func_arg2
 {
 public:
   Item *create_2_arg(THD *thd, Item *arg1, Item *arg2) override
-  { return new (thd->mem_root) Item_func_vec_distance_euclidean(thd, arg1, arg2); }
+  { return new (thd->mem_root)
+      Item_func_vec_distance(thd, arg1, arg2, Item_func_vec_distance::EUCLIDEAN); }
 
   static Create_func_vec_distance_euclidean s_singleton;
 
@@ -6274,7 +6275,8 @@ class Create_func_vec_distance_cosine: public Create_func_arg2
 {
 public:
   Item *create_2_arg(THD *thd, Item *arg1, Item *arg2) override
-  { return new (thd->mem_root) Item_func_vec_distance_cosine(thd, arg1, arg2); }
+  { return new (thd->mem_root)
+      Item_func_vec_distance(thd, arg1, arg2, Item_func_vec_distance::COSINE); }
 
   static Create_func_vec_distance_cosine s_singleton;
 

sql/item_vectorfunc.cc

@@ -24,7 +24,47 @@
 #include "vector_mhnsw.h"
 #include "sql_type_vector.h"
 
-key_map Item_func_vec_distance_common::part_of_sortkey() const
+static double calc_distance_euclidean(float *v1, float *v2, size_t v_len)
+{
+  double d= 0;
+  for (size_t i= 0; i < v_len; i++, v1++, v2++)
+  {
+    float dist= get_float(v1) - get_float(v2);
+    d+= dist * dist;
+  }
+  return sqrt(d);
+}
+
+static double calc_distance_cosine(float *v1, float *v2, size_t v_len)
+{
+  double dotp=0, abs1=0, abs2=0;
+  for (size_t i= 0; i < v_len; i++, v1++, v2++)
+  {
+    float f1= get_float(v1), f2= get_float(v2);
+    abs1+= f1 * f1;
+    abs2+= f2 * f2;
+    dotp+= f1 * f2;
+  }
+  return 1 - dotp/sqrt(abs1*abs2);
+}
+
+Item_func_vec_distance::Item_func_vec_distance(THD *thd, Item *a, Item *b,
+                                               distance_kind kind)
+ :Item_real_func(thd, a, b), kind(kind)
+{
+}
+
+bool Item_func_vec_distance::fix_length_and_dec(THD *thd)
+{
+  switch (kind) {
+  case EUCLIDEAN: calc_distance= calc_distance_euclidean; break;
+  case COSINE:    calc_distance= calc_distance_cosine; break;
+  }
+  set_maybe_null(); // if wrong dimensions
+  return Item_real_func::fix_length_and_dec(thd);
+}
+
+key_map Item_func_vec_distance::part_of_sortkey() const
 {
   key_map map(0);
   if (Item_field *item= get_field_arg())
@@ -33,13 +73,13 @@ key_map Item_func_vec_distance_common::part_of_sortkey() const
     KEY *keyinfo= f->table->s->key_info;
     for (uint i= f->table->s->keys; i < f->table->s->total_keys; i++)
       if (keyinfo[i].algorithm == HA_KEY_ALG_VECTOR && f->key_start.is_set(i)
-          && mhnsw_uses_distance(f->table, keyinfo + i, this))
+          && mhnsw_uses_distance(f->table, keyinfo + i) == kind)
         map.set_bit(i);
   }
   return map;
 }
 
-double Item_func_vec_distance_common::val_real()
+double Item_func_vec_distance::val_real()
 {
   String *r1= args[0]->val_str();
   String *r2= args[1]->val_str();

sql/item_vectorfunc.h

@@ -22,7 +22,7 @@
 #include "lex_string.h"
 #include "item_func.h"
 
-class Item_func_vec_distance_common: public Item_real_func
+class Item_func_vec_distance: public Item_real_func
 {
   Item_field *get_field_arg() const
   {
@@ -36,16 +36,20 @@ class Item_func_vec_distance_common: public Item_real_func
   {
     return check_argument_types_or_binary(NULL, 0, arg_count);
   }
-  virtual double calc_distance(float *v1, float *v2, size_t v_len) = 0;
+  double (*calc_distance)(float *v1, float *v2, size_t v_len);
 
 public:
-  Item_func_vec_distance_common(THD *thd, Item *a, Item *b)
-   :Item_real_func(thd, a, b) {}
-  bool fix_length_and_dec(THD *thd) override
+  enum distance_kind { EUCLIDEAN, COSINE } kind;
+  Item_func_vec_distance(THD *thd, Item *a, Item *b, distance_kind kind);
+  LEX_CSTRING func_name_cstring() const override
   {
-    set_maybe_null(); // if wrong dimensions
-    return Item_real_func::fix_length_and_dec(thd);
+    static LEX_CSTRING name[3]= {
+      { STRING_WITH_LEN("VEC_DISTANCE_EUCLIDEAN") },
+      { STRING_WITH_LEN("VEC_DISTANCE_COSINE") }
+    };
+    return name[kind];
   }
+  bool fix_length_and_dec(THD *thd) override;
   double val_real() override;
   Item *get_const_arg() const
   {
@@ -56,60 +60,8 @@ public:
     return NULL;
   }
   key_map part_of_sortkey() const override;
-};
-
-
-class Item_func_vec_distance_euclidean: public Item_func_vec_distance_common
-{
-  double calc_distance(float *v1, float *v2, size_t v_len) override
-  {
-    double d= 0;
-    for (size_t i= 0; i < v_len; i++, v1++, v2++)
-    {
-      float dist= get_float(v1) - get_float(v2);
-      d+= dist * dist;
-    }
-    return sqrt(d);
-  }
-
-public:
-  Item_func_vec_distance_euclidean(THD *thd, Item *a, Item *b)
-   :Item_func_vec_distance_common(thd, a, b) {}
-  LEX_CSTRING func_name_cstring() const override
-  {
-    static LEX_CSTRING name= { STRING_WITH_LEN("VEC_DISTANCE_EUCLIDEAN") };
-    return name;
-  }
   Item *do_get_copy(THD *thd) const override
-  { return get_item_copy<Item_func_vec_distance_euclidean>(thd, this); }
-};
-
-
-class Item_func_vec_distance_cosine: public Item_func_vec_distance_common
-{
-  double calc_distance(float *v1, float *v2, size_t v_len) override
-  {
-    double dotp=0, abs1=0, abs2=0;
-    for (size_t i= 0; i < v_len; i++, v1++, v2++)
-    {
-      float f1= get_float(v1), f2= get_float(v2);
-      abs1+= f1 * f1;
-      abs2+= f2 * f2;
-      dotp+= f1 * f2;
-    }
-    return 1 - dotp/sqrt(abs1*abs2);
-  }
-
-public:
-  Item_func_vec_distance_cosine(THD *thd, Item *a, Item *b)
-   :Item_func_vec_distance_common(thd, a, b) {}
-  LEX_CSTRING func_name_cstring() const override
-  {
-    static LEX_CSTRING name= { STRING_WITH_LEN("VEC_DISTANCE_COSINE") };
-    return name;
-  }
-  Item *do_get_copy(THD *thd) const override
-  { return get_item_copy<Item_func_vec_distance_cosine>(thd, this); }
+  { return get_item_copy<Item_func_vec_distance>(thd, this); }
 };
 
 

sql/vector_mhnsw.cc

@@ -20,7 +20,6 @@
 #include "create_options.h"
 #include "table_cache.h"
 #include "vector_mhnsw.h"
-#include "item_vectorfunc.h"
 #include <scope.h>
 #include <my_atomic_wrapper.h>
 #include "bloom_filters.h"
@@ -1290,7 +1289,7 @@ int mhnsw_read_first(TABLE *table, KEY *keyinfo, Item *dist, ulonglong limit)
 {
   THD *thd= table->in_use;
   TABLE *graph= table->hlindex;
-  auto *fun= static_cast<Item_func_vec_distance_common*>(dist->real_item());
+  auto *fun= static_cast<Item_func_vec_distance*>(dist->real_item());
   DBUG_ASSERT(fun);
 
   limit= std::min<ulonglong>(limit, max_ef);
@@ -1507,11 +1506,11 @@ const LEX_CSTRING mhnsw_hlindex_table_def(THD *thd, uint ref_length)
   return {s, len};
 }
 
-bool mhnsw_uses_distance(const TABLE *table, KEY *keyinfo, const Item *dist)
+Item_func_vec_distance::distance_kind mhnsw_uses_distance(const TABLE *table, KEY *keyinfo)
 {
   if (keyinfo->option_struct->metric == EUCLIDEAN)
-    return dynamic_cast<const Item_func_vec_distance_euclidean*>(dist) != NULL;
-  return dynamic_cast<const Item_func_vec_distance_cosine*>(dist) != NULL;
+    return Item_func_vec_distance::EUCLIDEAN;
+  return Item_func_vec_distance::COSINE;
 }
 
 /*

sql/vector_mhnsw.h

@@ -16,7 +16,7 @@
 */
 
 #include <my_global.h>
-#include "item.h"
+#include "item_vectorfunc.h"
 #include "m_string.h"
 #include "structs.h"
 #include "table.h"
@@ -33,7 +33,7 @@ int mhnsw_read_end(TABLE *table);
 int mhnsw_invalidate(TABLE *table, const uchar *rec, KEY *keyinfo);
 int mhnsw_delete_all(TABLE *table, KEY *keyinfo, bool truncate);
 void mhnsw_free(TABLE_SHARE *share);
-bool mhnsw_uses_distance(const TABLE *table, KEY *keyinfo, const Item *dist);
+Item_func_vec_distance::distance_kind mhnsw_uses_distance(const TABLE *table, KEY *keyinfo);
 
 extern ha_create_table_option mhnsw_index_options[];
 extern st_plugin_int *mhnsw_plugin;