MDEV-21195 INSERT chooses wrong partition for RANGE partitioning by DECIMAL column

Use FLOOR rounding for DECIMAL_RESULT item_expr in partition function.

1 files changed, 23 insertions, 3 deletions

diff --git a/sql/sql_partition.cc b/sql/sql_partition.cc
index 00a78ce3199..febd88c4b9b 100644
--- a/sql/sql_partition.cc
+++ b/sql/sql_partition.cc
@@ -2840,14 +2840,34 @@ bool partition_key_modified(TABLE *table, const MY_BITMAP *fields)
 
 static inline int part_val_int(Item *item_expr, longlong *result)
 {
-  *result= item_expr->val_int();
+  switch (item_expr->cmp_type())
+  {
+  case DECIMAL_RESULT:
+  {
+    my_decimal buf;
+    my_decimal *val= item_expr->val_decimal(&buf);
+    if (val && my_decimal2int(E_DEC_FATAL_ERROR, val, item_expr->unsigned_flag,
+                              result, FLOOR) != E_DEC_OK)
+      return true;
+    break;
+  }
+  case INT_RESULT:
+    *result= item_expr->val_int();
+    break;
+  case STRING_RESULT:
+  case REAL_RESULT:
+  case ROW_RESULT:
+  case TIME_RESULT:
+    DBUG_ASSERT(0);
+    break;
+  }
   if (item_expr->null_value)
   {
     if (unlikely(current_thd->is_error()))
-      return TRUE;
+      return true;
     *result= LONGLONG_MIN;
   }
-  return FALSE;
+  return false;
 }