Bug #26162: Trigger DML ignores low_priority_updates setting

  
The value of "low-priority-updates" option and the LOW PRIORITY
prefix was taken into account at parse time.
This caused triggers (among others) to ignore this flag (if
supplied for the DML statement).
Moved reading of the LOW_PRIORITY flag at run time.
Fixed an incosistency when handling
SET GLOBAL LOW_PRIORITY_UPDATES : now it is in effect for
delayed INSERTs.
Tested by checking the effect of LOW_PRIORITY flag via a 
trigger.


include/thr_lock.h:
  Bug #26162: moved reading of the LOW PRIORITY flag at run time
mysql-test/r/trigger.result:
  Bug #26162: test case
mysql-test/t/trigger.test:
  Bug #26162: test case
sql/set_var.cc:
  Bug #26162: fixed the handling of the "low-priority-updates" option
sql/sql_base.cc:
  Bug #26162: moved reading of the LOW PRIORITY flag at run time
sql/sql_yacc.yy:
  Bug #26162: moved reading of the LOW PRIORITY flag at run time

1 files changed, 55 insertions, 0 deletions

diff --git a/mysql-test/t/trigger.test b/mysql-test/t/trigger.test
index 82de4dac111..24817de66be 100644
--- a/mysql-test/t/trigger.test
+++ b/mysql-test/t/trigger.test
@@ -1763,4 +1763,59 @@ select * from t1;
 select * from t3;
 drop table t1, t2, t3;
 
+#
+# Bug #26162: Trigger DML ignores low_priority_updates setting
+#
+CREATE TABLE t1 (id INTEGER);
+CREATE TABLE t2 (id INTEGER);
+
+INSERT INTO t2 VALUES (1),(2);
+
+# trigger that produces the high priority insert, but should be low, adding
+# LOW_PRIORITY fixes this
+CREATE TRIGGER t1_test AFTER INSERT ON t1 FOR EACH ROW 
+  INSERT INTO t2 VALUES (new.id);
+
+CONNECT (rl_acquirer,  localhost, root,,);
+CONNECT (wl_acquirer,  localhost, root,,);
+CONNECT (rl_contender, localhost, root,,);
+
+SELECT GET_LOCK('B26162',20);
+
+CONNECTION rl_acquirer;
+--send
+SELECT 'rl_acquirer', GET_LOCK('B26162',5), id FROM t2 WHERE id = 1;
+
+CONNECTION wl_acquirer;
+SET SESSION LOW_PRIORITY_UPDATES=1;
+SET GLOBAL LOW_PRIORITY_UPDATES=1;
+--send
+INSERT INTO t1 VALUES (5);
+
+CONNECTION rl_contender;
+# must not "see" the row inserted by the INSERT (as it must run before the
+# INSERT)
+--send
+SELECT 'rl_contender', id FROM t2 WHERE id > 1;
+
+CONNECTION default;
+SELECT RELEASE_LOCK('B26162');
+
+CONNECTION wl_acquirer;
+--reap
+CONNECTION rl_acquirer;
+--reap
+CONNECTION rl_contender;
+--reap
+
+CONNECTION default;
+DISCONNECT rl_acquirer;
+DISCONNECT wl_acquirer;
+DISCONNECT rl_contender;
+
+DROP TRIGGER t1_test;
+DROP TABLE t1,t2;
+SET SESSION LOW_PRIORITY_UPDATES=DEFAULT;
+SET GLOBAL LOW_PRIORITY_UPDATES=DEFAULT;
+
 --echo End of 5.0 tests