MDEV-6979 simplify trigger rules for RBR triggers

Rows_log_event::write_row - don't optimize DELETE+INSERT
into UPDATE if RBR triggers are used

mysql-test/suite/rpl/r/rpl_row_triggers.result

@@ -65,7 +65,7 @@ i0	1		a
 i1	1		a
 u0	1	a	d
 u1	1	a	d
-# INSERT triggers which cause also UPDATE test (insert duplicate row)
+# INSERT triggers causing DELETE + INSERT (on unique key conflict)
 insert into t1 values ('0','1');
 SELECT * FROM t2 order by id;
 id	cnt	o	n
@@ -78,12 +78,12 @@ u1	1	a	d
 insert into t1 values ('0','1');
 SELECT * FROM t2 order by id;
 id	cnt	o	n
-d0	1	d	
-d1	1	d	
+d0	2	0	
+d1	2	0	
 i0	3		0
 i1	3		0
-u0	2	0	0
-u1	2	0	0
+u0	1	a	d
+u1	1	a	d
 # INSERT triggers which cause also DELETE test
 # (insert duplicate row in table referenced by foreign key)
 insert into t1 values ('1','1');
@@ -91,12 +91,12 @@ CREATE TABLE t3 (C1 CHAR(1) primary key, FOREIGN KEY (C1) REFERENCES t1(C1) ) en
 insert into t1 values ('1','1');
 SELECT * FROM t2 order by id;
 id	cnt	o	n
-d0	2	1	
-d1	2	1	
+d0	3	1	
+d1	3	1	
 i0	5		1
 i1	5		1
-u0	2	0	0
-u1	2	0	0
+u0	1	a	d
+u1	1	a	d
 drop table t3,t1;
 SET @@global.slave_exec_mode= @old_slave_exec_mode;
 SET @@global.slave_run_triggers_for_rbr= @old_slave_run_triggers_for_rbr;

mysql-test/suite/rpl/t/rpl_row_triggers.test

@@ -64,7 +64,7 @@ sync_slave_with_master;
 connection slave;
 SELECT * FROM t2 order by id;
 
---echo # INSERT triggers which cause also UPDATE test (insert duplicate row)
+--echo # INSERT triggers causing DELETE + INSERT (on unique key conflict)
 insert into t1 values ('0','1');
 
 SELECT * FROM t2 order by id;

sql/log_event.cc

@@ -11471,16 +11471,14 @@ Rows_log_event::write_row(rpl_group_info *rgi,
        then there might be another key for which the unique check will
        fail, so we're better off just deleting the row and inserting
        the correct row.
+
+       Additionally we don't use UPDATE if rbr triggers should be invoked -
+       when triggers are used we want a simple and predictable execution path.
      */
-    if (last_uniq_key(table, keynum) &&
+    if (last_uniq_key(table, keynum) && !invoke_triggers &&
         !table->file->referenced_by_foreign_key())
     {
       DBUG_PRINT("info",("Updating row using ha_update_row()"));
-      if (invoke_triggers &&
-          process_triggers(TRG_EVENT_UPDATE, TRG_ACTION_BEFORE, FALSE))
-        error= HA_ERR_GENERIC; // in case if error is not set yet
-      else
-      {
       error= table->file->ha_update_row(table->record[1],
                                        table->record[0]);
       switch (error) {
@@ -11497,11 +11495,6 @@ Rows_log_event::write_row(rpl_group_info *rgi,
         DBUG_PRINT("info",("ha_update_row() returns error %d",error));
         table->file->print_error(error, MYF(0));
       }
-        if (invoke_triggers && !error &&
-            (process_triggers(TRG_EVENT_UPDATE, TRG_ACTION_AFTER, TRUE) ||
-             process_triggers(TRG_EVENT_INSERT, TRG_ACTION_AFTER, TRUE)))
-          error= HA_ERR_GENERIC; // in case if error is not set yet
-      }
 
       DBUG_RETURN(error);
     }