versioning: use @@timestamp

Don't use hidden system time in versioning,
but keep the system time logic in THD
to workaround low-res system clock and
replication not versioned to versioned.

This reverts MDEV-14788 (System versioning cannot
be based on local timestamps, as it is now).
Versioning is based on local timestamps again,
but timestamps are protected by MDEV-15923
(option to control who can set session @@timestamp).

mysql-test/suite/versioning/r/insert2.result

@@ -71,24 +71,6 @@ i	c	current_row
 1	foo	1
 drop table t1;
 drop table t2;
-set timestamp=1000000019;
-select now() < sysdate();
-now() < sysdate()
-1
-create table t1 (a int) with system versioning;
-insert t1 values (1);
-set @a=sysdate(6);
-select * from t1 for system_time as of now(6);
-a
-select * from t1 for system_time as of sysdate(6);
-a
-1
-update t1 set a=2;
-delete from t1;
-select *, row_start > @a, row_end > @a from t1 for system_time all;
-a	row_start > @a	row_end > @a
-1	0	1
-2	1	1
 #
 # MDEV-14871 Server crashes in fill_record / fill_record_n_invoke_before_triggers upon inserting into versioned table with trigger
 #

mysql-test/suite/versioning/r/partition_rotation.result

@@ -1,5 +1,3 @@
-include/master-slave.inc
-[connection master]
 set timestamp=unix_timestamp('2001-02-03 10:20:30');
 create or replace table t1 (i int) with system versioning
 partition by system_time interval 1 day
@@ -10,22 +8,23 @@ insert t1 values (1);
 delete from t1;
 set timestamp=unix_timestamp('2001-02-04 10:20:50');
 insert t1 values (2);
+Warnings:
+Warning	4114	Versioned table `test`.`t1`: partition `p1` is full, add more HISTORY partitions
 delete from t1;
-connection slave;
+Warnings:
+Warning	4114	Versioned table `test`.`t1`: partition `p1` is full, add more HISTORY partitions
 select subpartition_name,partition_description,table_rows from information_schema.partitions where table_schema='test' and table_name='t1';
 subpartition_name	partition_description	table_rows
 p1sp0	2001-02-04 10:20:30	1
 p1sp1	2001-02-04 10:20:30	1
 pnsp0	CURRENT	0
 pnsp1	CURRENT	0
-connection master;
 set timestamp=unix_timestamp('2001-02-04 10:20:55');
 alter table t1 add partition (partition p0 history, partition p2 history);
 set timestamp=unix_timestamp('2001-02-04 10:30:00');
 insert t1 values (4),(5);
 set timestamp=unix_timestamp('2001-02-04 10:30:10');
 update t1 set i=6 where i=5;
-connection slave;
 select subpartition_name,partition_description,table_rows from information_schema.partitions where table_schema='test' and table_name='t1';
 subpartition_name	partition_description	table_rows
 p1sp0	2001-02-04 10:20:30	1
@@ -56,6 +55,4 @@ i
 explain partitions select * from t1 for system_time all where row_end = @ts;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	p1_p1sp0,p1_p1sp1	#	NULL	NULL	NULL	NULL	#	#
-connection master;
 drop table t1;
-include/rpl_end.inc

mysql-test/suite/versioning/t/insert2.test

@@ -69,24 +69,6 @@ select i, c, e>TIMESTAMP'2038-01-01 00:00:00' AS current_row from t1;
 drop table t1;
 drop table t2;
 
-#
-# MDEV-14788 System versioning cannot be based on local timestamps, as it is now
-#
-set timestamp=1000000019;
-select now() < sysdate();
-create table t1 (a int) with system versioning;
-insert t1 values (1);
-
---source suite/versioning/wait_system_clock.inc
-set @a=sysdate(6);
-
-select * from t1 for system_time as of now(6);
-select * from t1 for system_time as of sysdate(6);
-update t1 set a=2;
-delete from t1;
---sorted_result
-select *, row_start > @a, row_end > @a from t1 for system_time all;
-
 --echo #
 --echo # MDEV-14871 Server crashes in fill_record / fill_record_n_invoke_before_triggers upon inserting into versioned table with trigger
 --echo #

mysql-test/suite/versioning/t/partition_rotation.test

@@ -1,17 +1,8 @@
 --source include/have_partition.inc
---source include/have_binlog_format_statement.inc
---source include/master-slave.inc
-
-#
-# The test below isn't a replication test as such,
-# but it uses replication to get custom timestamps and repeatable
-# behavior into versioning.
-#
 
 #
 # partition rotation
 #
-disable_warnings;
 set timestamp=unix_timestamp('2001-02-03 10:20:30');
 create or replace table t1 (i int) with system versioning
 partition by system_time interval 1 day
@@ -21,17 +12,16 @@ set timestamp=unix_timestamp('2001-02-03 10:20:40');
 insert t1 values (1); delete from t1;
 set timestamp=unix_timestamp('2001-02-04 10:20:50');
 insert t1 values (2); delete from t1;
-enable_warnings;
+
-sync_slave_with_master;
 select subpartition_name,partition_description,table_rows from information_schema.partitions where table_schema='test' and table_name='t1';
-connection master;
+
 set timestamp=unix_timestamp('2001-02-04 10:20:55');
 alter table t1 add partition (partition p0 history, partition p2 history);
 set timestamp=unix_timestamp('2001-02-04 10:30:00');
 insert t1 values (4),(5);
 set timestamp=unix_timestamp('2001-02-04 10:30:10');
 update t1 set i=6 where i=5;
-sync_slave_with_master;
+
 select subpartition_name,partition_description,table_rows from information_schema.partitions where table_schema='test' and table_name='t1';
 
 --echo ## pruning check
@@ -47,7 +37,4 @@ select * from t1 for system_time all where row_end = @ts;
 --replace_column 5 # 10 # 11 #
 explain partitions select * from t1 for system_time all where row_end = @ts;
 
-connection master;
 drop table t1;
-
---source include/rpl_end.inc

sql/partition_info.cc

@@ -859,7 +859,7 @@ void partition_info::vers_set_hist_part(THD *thd)
 
   if (vers_info->interval.is_set())
   {
-    if (vers_info->hist_part->range_value > thd->systime())
+    if (vers_info->hist_part->range_value > thd->query_start())
       return;
 
     partition_element *next= NULL;
@@ -870,7 +870,7 @@ void partition_info::vers_set_hist_part(THD *thd)
     while ((next= it++) != vers_info->now_part)
     {
       vers_info->hist_part= next;
-      if (next->range_value > thd->systime())
+      if (next->range_value > thd->query_start())
         return;
     }
     goto warn;

sql/sql_class.h

@@ -3437,16 +3437,13 @@ public:
   { query_start_sec_part_used=1; return start_time_sec_part; }
   MYSQL_TIME query_start_TIME();
 
+private:
   struct {
     my_hrtime_t start;
     my_time_t sec;
     ulong sec_part;
   } system_time;
 
-  ulong systime_sec_part() { query_start_sec_part_used=1; return system_time.sec_part; }
-  my_time_t systime() { return system_time.sec; }
-
-private:
   void set_system_time()
   {
     my_hrtime_t hrtime= my_hrtime();
@@ -3471,29 +3468,9 @@ private:
     }
   }
 
-  void set_system_time_from_user_time(bool with_sec_part)
-  {
-    if (with_sec_part)
-    {
-      system_time.sec= start_time;
-      system_time.sec_part= start_time_sec_part;
-    }
-    else
-    {
-      if (system_time.sec == start_time)
-        system_time.sec_part++;
-      else
-      {
-        system_time.sec= start_time;
-        system_time.sec_part= 0;
-      }
-    }
-  }
-
 public:
   inline void set_start_time()
   {
-    set_system_time();
     if (user_time.val)
     {
       start_time= hrtime_to_my_time(user_time);
@@ -3501,6 +3478,7 @@ public:
     }
     else
     {
+      set_system_time();
       start_time= system_time.sec;
       start_time_sec_part= system_time.sec_part;
     }
@@ -3511,6 +3489,7 @@ public:
     set_start_time();
     start_utime= utime_after_lock= microsecond_interval_timer();
   }
+  /* only used in SET @@timestamp=... */
   inline void set_time(my_hrtime_t t)
   {
     user_time= t;
@@ -3525,14 +3504,23 @@ public:
     if (opt_secure_timestamp > (slave_thread ? SECTIME_REPL : SECTIME_SUPER))
       set_time();                 // note that BINLOG itself requires SUPER
     else
+    {
+      if (sec_part <= TIME_MAX_SECOND_PART)
+      {
+        start_time= system_time.sec= t;
+        start_time_sec_part= system_time.sec_part= sec_part;
+      }
+      else if (t != system_time.sec)
+      {
+        start_time= system_time.sec= t;
+        start_time_sec_part= system_time.sec_part= 0;
+      }
+      else
       {
         start_time= t;
-      start_time_sec_part= sec_part > TIME_MAX_SECOND_PART ? 0 : sec_part;
+        start_time_sec_part= ++system_time.sec_part;
+      }
       user_time.val= hrtime_from_time(start_time) + start_time_sec_part;
-      if (slave_thread)
-        set_system_time_from_user_time(sec_part <= TIME_MAX_SECOND_PART);
-      else // BINLOG command
-        set_system_time();
       PSI_CALL_set_thread_start_time(start_time);
       start_utime= utime_after_lock= microsecond_interval_timer();
     }

sql/sql_partition.cc

@@ -1571,7 +1571,7 @@ static bool check_vers_constants(THD *thd, partition_info *part_info)
       my_tz_OFFSET0->TIME_to_gmt_sec(&ltime, &error);
     if (error)
       goto err;
-    if (vers_info->hist_part->range_value <= thd->systime())
+    if (vers_info->hist_part->range_value <= thd->query_start())
       vers_info->hist_part= el;
   }
   return 0;
@@ -5310,7 +5310,7 @@ that are reorganised.
           if (*fast_alter_table && tab_part_info->vers_info->interval.is_set())
           {
             partition_element *hist_part= tab_part_info->vers_info->hist_part;
-            if (hist_part->range_value <= thd->systime())
+            if (hist_part->range_value <= thd->query_start())
               hist_part->part_state= PART_CHANGED;
           }
         }

sql/sql_yacc.yy

@@ -5907,7 +5907,7 @@ opt_versioning_rotation:
 opt_versioning_interval_start:
          /* empty */
          {
-           $$= thd->systime();
+           $$= thd->query_start();
          }
        | STARTS_SYM ulong_num
          {

sql/table.cc

@@ -7752,8 +7752,8 @@ void TABLE::vers_update_fields()
   {
     if (!vers_write)
       return;
-    if (vers_start_field()->store_timestamp(in_use->systime(),
+    if (vers_start_field()->store_timestamp(in_use->query_start(),
-                                            in_use->systime_sec_part()))
+                                            in_use->query_start_sec_part()))
       DBUG_ASSERT(0);
   }
   else
@@ -7768,8 +7768,8 @@ void TABLE::vers_update_fields()
 
 void TABLE::vers_update_end()
 {
-  if (vers_end_field()->store_timestamp(in_use->systime(),
+  if (vers_end_field()->store_timestamp(in_use->query_start(),
-                                        in_use->systime_sec_part()))
+                                        in_use->query_start_sec_part()))
     DBUG_ASSERT(0);
 }
 
@@ -8611,9 +8611,9 @@ bool TR_table::update(ulonglong start_id, ulonglong end_id)
   if (!table && open())
     return true;
 
-  timeval start_time= {thd->systime(), long(thd->systime_sec_part())};
+  timeval start_time= {thd->query_start(), long(thd->query_start_sec_part())};
   thd->set_start_time();
-  timeval end_time= {thd->systime(), long(thd->systime_sec_part())};
+  timeval end_time= {thd->query_start(), long(thd->query_start_sec_part())};
   store(FLD_TRX_ID, start_id);
   store(FLD_COMMIT_ID, end_id);
   store(FLD_BEGIN_TS, start_time);