MDEV-16991 Rounding vs truncation for TIME, DATETIME, TIMESTAMPbb-10.4-mdev16991

1 files changed, 16 insertions, 6 deletions

diff --git a/sql/event_data_objects.cc b/sql/event_data_objects.cc
index a6803982171..db056a9f08e 100644
--- a/sql/event_data_objects.cc
+++ b/sql/event_data_objects.cc
@@ -479,14 +479,24 @@ Event_queue_element::load_from_row(THD *thd, TABLE *table)
   uint not_used;
   if (!starts_null)
   {
-    table->field[ET_FIELD_STARTS]->get_date(&time, TIME_NO_ZERO_DATE);
+    /*
+      The expected data type for these columns in mysql.events:
+        starts, ends, execute_at, last_executed
+      is DATETIME. No nanosecond truncation should normally be needed,
+      unless the DBA changes them, e.g. to VARCHAR, DECIMAL, etc.
+      For this unexpected case let's use the default round mode,
+      according to the current session settings.
+    */
+    table->field[ET_FIELD_STARTS]->get_date(&time, TIME_NO_ZERO_DATE |
+                                                   thd->temporal_round_mode());
     starts= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);
   }
 
   ends_null= table->field[ET_FIELD_ENDS]->is_null();
   if (!ends_null)
   {
-    table->field[ET_FIELD_ENDS]->get_date(&time, TIME_NO_ZERO_DATE);
+    table->field[ET_FIELD_ENDS]->get_date(&time, TIME_NO_ZERO_DATE |
+                                                 thd->temporal_round_mode());
     ends= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);
   }
 
@@ -502,8 +512,8 @@ Event_queue_element::load_from_row(THD *thd, TABLE *table)
   DBUG_ASSERT(!(starts_null && ends_null && !expression && execute_at_null));
   if (!expression && !execute_at_null)
   {
-    if (table->field[ET_FIELD_EXECUTE_AT]->get_date(&time,
-                                                    TIME_NO_ZERO_DATE))
+    if (table->field[ET_FIELD_EXECUTE_AT]->get_date(&time, TIME_NO_ZERO_DATE |
+                                                    thd->temporal_round_mode()))
       DBUG_RETURN(TRUE);
     execute_at= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);
   }
@@ -535,8 +545,8 @@ Event_queue_element::load_from_row(THD *thd, TABLE *table)
 
   if (!table->field[ET_FIELD_LAST_EXECUTED]->is_null())
   {
-    table->field[ET_FIELD_LAST_EXECUTED]->get_date(&time,
-                                                   TIME_NO_ZERO_DATE);
+    table->field[ET_FIELD_LAST_EXECUTED]->get_date(&time, TIME_NO_ZERO_DATE |
+                                                   thd->temporal_round_mode());
     last_executed= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);
   }