MDEV-17698 MEMORY engine performance regression

1 files changed, 28 insertions, 0 deletions

diff --git a/sql/sql_type_int.h b/sql/sql_type_int.h
index 1eda5651df5..7433bd5249f 100644
--- a/sql/sql_type_int.h
+++ b/sql/sql_type_int.h
@@ -24,12 +24,25 @@ class Longlong_hybrid
 protected:
   longlong m_value;
   bool m_unsigned;
+  int cmp_signed(const Longlong_hybrid& other) const
+  {
+    return m_value < other.m_value ? -1 : m_value == other.m_value ? 0 : 1;
+  }
+  int cmp_unsigned(const Longlong_hybrid& other) const
+  {
+    return (ulonglong) m_value < (ulonglong) other.m_value ? -1 :
+            m_value == other.m_value ? 0 : 1;
+  }
 public:
   Longlong_hybrid(longlong nr, bool unsigned_flag)
    :m_value(nr), m_unsigned(unsigned_flag)
   { }
   longlong value() const { return m_value; }
   bool is_unsigned() const { return m_unsigned; }
+  bool is_unsigned_outside_of_signed_range() const
+  {
+    return m_unsigned && ((ulonglong) m_value) > (ulonglong) LONGLONG_MAX;
+  }
   bool neg() const { return m_value < 0 && !m_unsigned; }
   ulonglong abs() const
   {
@@ -39,6 +52,21 @@ public:
       return ((ulonglong) LONGLONG_MAX) + 1;
     return m_value < 0 ? -m_value : m_value;
   }
+  int cmp(const Longlong_hybrid& other) const
+  {
+    if (m_unsigned == other.m_unsigned)
+      return m_unsigned ? cmp_unsigned(other) : cmp_signed(other);
+    if (is_unsigned_outside_of_signed_range())
+      return 1;
+    if (other.is_unsigned_outside_of_signed_range())
+      return -1;
+    /*
+      The unsigned argument is in the range 0..LONGLONG_MAX.
+      The signed argument is in the range LONGLONG_MIN..LONGLONG_MAX.
+      Safe to compare as signed.
+    */
+    return cmp_signed(other);
+  }
 };
 
 #endif // SQL_TYPE_INT_INCLUDED