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Fix for bug #12704 "Server crashes during trigger execution".

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This bug occurs when some trigger for table used by DML statement is created
or changed while statement was waiting in lock_tables(). In this situation
prelocking set which we have calculated becames invalid which can easily lead
to errors and even in some cases to crashes.

With proposed patch we no longer silently reopen tables in lock_tables(),
instead caller of lock_tables() becomes responsible for reopening tables and
recalculation of prelocking set.
This commit is contained in:
dlenev@mysql.com
2005-09-15 03:56:09 +04:00
parent 9300833c91
commit e231ebe5fb
16 changed files with 414 additions and 97 deletions
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116
mysql-test/t/trigger.test
View File

@@ -10,6 +10,11 @@ drop function if exists f1;
drop procedure if exists p1;
--enable_warnings
# Create additional connections used through test
connect (addconroot1, localhost, root,,);
connect (addconroot2, localhost, root,,);
connection default;
create table t1 (i int);
# let us test some very simple trigger
@@ -680,12 +685,10 @@ end|
delimiter ;|
update t1 set data = 1;
connect (addconroot, localhost, root,,);
connection addconroot;
connection addconroot1;
update t1 set data = 2;
connection default;
disconnect addconroot;
drop table t1;
#
@@ -765,3 +768,110 @@ insert into t1 values (3);
select * from t1;
drop trigger t1_bi;
drop tables t1, t2;
# Tests for bug #12704 "Server crashes during trigger execution".
# If we run DML statements and CREATE TRIGGER statements concurrently
# it may happen that trigger will be created while DML statement is
# waiting for table lock. In this case we have to reopen tables and
# recalculate prelocking set.
# Unfortunately these tests rely on the order in which tables are locked
# by statement so they are non determenistic and are disabled.
--disable_parsing
create table t1 (id int);
create table t2 (id int);
create table t3 (id int);
create function f1() returns int return (select max(id)+2 from t2);
create view v1 as select f1() as f;
# Let us check that we notice trigger at all
connection addconroot1;
lock tables t2 write;
connection default;
send insert into t1 values ((select max(id) from t2)), (2);
--sleep 1
connection addconroot2;
create trigger t1_trg before insert on t1 for each row set NEW.id:= 1;
connection addconroot1;
unlock tables;
connection default;
reap;
select * from t1;
# Check that we properly calculate new prelocking set
insert into t2 values (3);
connection addconroot1;
lock tables t2 write;
connection default;
send insert into t1 values ((select max(id) from t2)), (4);
--sleep 1
connection addconroot2;
drop trigger t1_trg;
create trigger t1_trg before insert on t1 for each row
insert into t3 values (new.id);
connection addconroot1;
unlock tables;
connection default;
reap;
select * from t1;
select * from t3;
# We should be able to do this even if fancy views are involved
connection addconroot1;
lock tables t2 write;
connection default;
send insert into t1 values ((select max(f) from v1)), (6);
--sleep 1
connection addconroot2;
drop trigger t1_trg;
create trigger t1_trg before insert on t1 for each row
insert into t3 values (new.id + 100);
connection addconroot1;
unlock tables;
connection default;
reap;
select * from t1;
select * from t3;
# This also should work for multi-update
# Let us drop trigger to demonstrate that prelocking set is really
# rebuilt
drop trigger t1_trg;
connection addconroot1;
lock tables t2 write;
connection default;
send update t1, t2 set t1.id=10 where t1.id=t2.id;
--sleep 1
connection addconroot2;
create trigger t1_trg before update on t1 for each row
insert into t3 values (new.id);
connection addconroot1;
unlock tables;
connection default;
reap;
select * from t1;
select * from t3;
# And even for multi-update converted from ordinary update thanks to view
drop view v1;
drop trigger t1_trg;
create view v1 as select t1.id as id1 from t1, t2 where t1.id= t2.id;
insert into t2 values (10);
connection addconroot1;
lock tables t2 write;
connection default;
send update v1 set id1= 11;
--sleep 1
connection addconroot2;
create trigger t1_trg before update on t1 for each row
insert into t3 values (new.id + 100);
connection addconroot1;
unlock tables;
connection default;
reap;
select * from t1;
select * from t3;
drop function f1;
drop view v1;
drop table t1, t2, t3;
--enable_parsing