MDEV-17124: mariadb 10.1.34, views and prepared statements: ERROR 1615 (HY000): Prepared statement needs to be re-preparedbb-10.2-MDEV-17124

The problem is that if table definition cache (TDC) is full of real tables
which are in tables cache, view definition can not stay there so will be
removed by its own underlying tables.
In situation above old mechanism of detection matching definition in PS
and current version always require reprepare and so prevent executing
the PS.

One work around is to increase TDC, other - improve version check for
views/triggers (which is done here). Now in suspicious cases we check:
 - timestamp (ms) of the view to be sure that version really have changed;
 - time (ms) of creation of a trigger related to time (ms) of statement
   preparation.

1 files changed, 11 insertions, 7 deletions

diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index 9483db9eff9..138fa4bc631 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -6724,13 +6724,15 @@ static bool store_trigger(THD *thd, Trigger *trigger,
   table->field[14]->store(STRING_WITH_LEN("OLD"), cs);
   table->field[15]->store(STRING_WITH_LEN("NEW"), cs);
 
-  if (trigger->create_time)
+  if (trigger->ms_create_time)
   {
+    /* timestamp is in microseconds */
     table->field[16]->set_notnull();
     thd->variables.time_zone->gmt_sec_to_TIME(&timestamp,
-                                              (my_time_t)(trigger->create_time/100));
-    /* timestamp is with 6 digits */
-    timestamp.second_part= (trigger->create_time % 100) * 10000;
+                                              (my_time_t)
+                                              (trigger->ms_create_time/
+                                               1000000));
+    timestamp.second_part= trigger->ms_create_time % 1000000;
     ((Field_temporal_with_date*) table->field[16])->store_time_dec(&timestamp,
                                                                    2);
   }
@@ -9810,12 +9812,14 @@ static bool show_create_trigger_impl(THD *thd, Trigger *trigger)
            trigger->db_cl_name.length,
            system_charset_info);
 
-  if (trigger->create_time)
+  if (trigger->ms_create_time)
   {
     MYSQL_TIME timestamp;
     thd->variables.time_zone->gmt_sec_to_TIME(&timestamp,
-                                              (my_time_t)(trigger->create_time/100));
-    timestamp.second_part= (trigger->create_time % 100) * 10000;
+                                              (my_time_t)
+                                              (trigger->ms_create_time/
+                                               1000000));
+    timestamp.second_part= trigger->ms_create_time % 1000000;
     p->store(&timestamp, 2);
   }
   else