Bug#47925: regression of range optimizer and date comparison in 5.1.39!

When a query was using a DATE or DATETIME value formatted
using any other separator characters beside hyphen '-', a
query with a greater-or-equal '>=' condition matching only
the greatest value in an indexed column, the result was
empty if index range scan was employed.

The range optimizer got a new feature between 5.1.38 and
5.1.39 that changes a greater-or-equal condition to a
greater-than if the value matching that in the query was not
present in the table. But the value comparison function
compared the dates as strings instead of dates.

The bug was fixed by splitting the function
get_date_from_str in two: One part that parses and does
error checking. This function is now visible outside the
module. The old get_date_from_str now calls the new
function.


mysql-test/r/range.result:
  Bug#47925: Test result
mysql-test/t/range.test:
  Bug#47925: Test case
sql/item.cc:
  Bug#47925: Fix + some edit on the comments
sql/item.h:
  Bug#47925: Changed function signature
sql/item_cmpfunc.cc:
  Bug#47925: Split function in two
sql/item_cmpfunc.h:
  Bug#47925: Declaration of new function
sql/opt_range.cc:
  Bug#47925: Added THD to function call
sql/time.cc:
  Bug#47925: Added microsecond comparison

1 files changed, 63 insertions, 37 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index c29031d25b5..9fc52bb8876 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -636,56 +636,51 @@ int Arg_comparator::set_compare_func(Item_bool_func2 *item, Item_result type)
   return 0;
 }
 
-
 /**
-  @brief Convert date provided in a string to the int representation.
-
-  @param[in]   thd        thread handle
-  @param[in]   str        a string to convert
-  @param[in]   warn_type  type of the timestamp for issuing the warning
-  @param[in]   warn_name  field name for issuing the warning
-  @param[out]  error_arg  could not extract a DATE or DATETIME
-
-  @details Convert date provided in the string str to the int
-    representation.  If the string contains wrong date or doesn't
-    contain it at all then a warning is issued.  The warn_type and
-    the warn_name arguments are used as the name and the type of the
-    field when issuing the warning.  If any input was discarded
-    (trailing or non-timestampy characters), was_cut will be non-zero.
-    was_type will return the type str_to_datetime() could correctly
-    extract.
-
-  @return
-    converted value. 0 on error and on zero-dates -- check 'failure'
+  Parse date provided in a string to a MYSQL_TIME.
+
+  @param[in]   thd        Thread handle
+  @param[in]   str        A string to convert
+  @param[in]   warn_type  Type of the timestamp for issuing the warning
+  @param[in]   warn_name  Field name for issuing the warning
+  @param[out]  l_time     The MYSQL_TIME objects is initialized.
+
+  Parses a date provided in the string str into a MYSQL_TIME object. If the
+  string contains an incorrect date or doesn't correspond to a date at all
+  then a warning is issued. The warn_type and the warn_name arguments are used
+  as the name and the type of the field when issuing the warning. If any input
+  was discarded (trailing or non-timestamp-y characters), return value will be
+  TRUE.
+
+  @return Status flag
+  @retval FALSE Success.
+  @retval True Indicates failure.
 */
 
-static ulonglong
-get_date_from_str(THD *thd, String *str, timestamp_type warn_type,
-                  char *warn_name, bool *error_arg)
+bool get_mysql_time_from_str(THD *thd, String *str, timestamp_type warn_type, 
+                             const char *warn_name, MYSQL_TIME *l_time)
 {
-  ulonglong value= 0;
+  bool value;
   int error;
-  MYSQL_TIME l_time;
-  enum_mysql_timestamp_type ret;
+  enum_mysql_timestamp_type timestamp_type;
 
-  ret= str_to_datetime(str->ptr(), str->length(), &l_time,
-                       (TIME_FUZZY_DATE | MODE_INVALID_DATES |
-                        (thd->variables.sql_mode &
-                         (MODE_NO_ZERO_IN_DATE | MODE_NO_ZERO_DATE))),
-                       &error);
+  timestamp_type= 
+    str_to_datetime(str->ptr(), str->length(), l_time,
+                    (TIME_FUZZY_DATE | MODE_INVALID_DATES |
+                     (thd->variables.sql_mode &
+                      (MODE_NO_ZERO_IN_DATE | MODE_NO_ZERO_DATE))),
+                    &error);
 
-  if (ret == MYSQL_TIMESTAMP_DATETIME || ret == MYSQL_TIMESTAMP_DATE)
-  {
+  if (timestamp_type == MYSQL_TIMESTAMP_DATETIME || 
+      timestamp_type == MYSQL_TIMESTAMP_DATE)
     /*
       Do not return yet, we may still want to throw a "trailing garbage"
       warning.
     */
-    *error_arg= FALSE;
-    value= TIME_to_ulonglong_datetime(&l_time);
-  }
+    value= FALSE;
   else
   {
-    *error_arg= TRUE;
+    value= TRUE;
     error= 1;                                   /* force warning */
   }
 
@@ -698,6 +693,37 @@ get_date_from_str(THD *thd, String *str, timestamp_type warn_type,
 }
 
 
+/**
+  @brief Convert date provided in a string to the int representation.
+
+  @param[in]   thd        thread handle
+  @param[in]   str        a string to convert
+  @param[in]   warn_type  type of the timestamp for issuing the warning
+  @param[in]   warn_name  field name for issuing the warning
+  @param[out]  error_arg  could not extract a DATE or DATETIME
+
+  @details Convert date provided in the string str to the int
+    representation.  If the string contains wrong date or doesn't
+    contain it at all then a warning is issued.  The warn_type and
+    the warn_name arguments are used as the name and the type of the
+    field when issuing the warning.
+
+  @return
+    converted value. 0 on error and on zero-dates -- check 'failure'
+*/
+static ulonglong get_date_from_str(THD *thd, String *str, 
+                                   timestamp_type warn_type, 
+                                   const char *warn_name, bool *error_arg)
+{
+  MYSQL_TIME l_time;
+  *error_arg= get_mysql_time_from_str(thd, str, warn_type, warn_name, &l_time);
+
+  if (*error_arg)
+    return 0;
+  return TIME_to_ulonglong_datetime(&l_time);
+}
+
+
 /*
   Check whether compare_datetime() can be used to compare items.