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Backport of:

Browse Source 
------------------------------------------------------------
revno: 3035.4.1
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 39897-6.0
timestamp: Thu 2009-01-15 12:17:57 -0200
message:
Bug#39897: lock_multi fails in pushbuild: timeout waiting for processlist

The problem is that relying on the "Table lock" thread state in
its current position to detect that a thread is waiting on a lock
is race prone. The "Table lock" state change happens before the
thread actually tries to grab a lock on a table.

The solution is to move the "Table lock" state so that its set
only when a thread is actually going to wait for a lock. The state
change happens after the thread fails to grab the lock (because it
is owned by other thread) and proceeds to wait on a condition.

This is considered part of work related to WL#4284 "Transactional
DDL locking"
Warning: this patch contains an incompatible change. 
When waiting on a lock in thr_lock.c, the server used to display "Locked"
processlist state. After this patch, the state is "Table lock".
The new state was actually intended to be display since year 2002,
when Monty added it. But up until removal of thd->locked boolean
member, this state was ignored by SHOW PROCESSLIST code.
This commit is contained in:
Konstantin Osipov
2009-12-03 23:08:27 +03:00
parent 36897c862b
commit c44665aeb1
12 changed files with 33 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
mysql-test/t/lock_multi.test
View File

@ -22,7 +22,7 @@ connection reader;
# Sleep a bit till the update of connection writer is in work and hangs
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info = "update low_priority t1 set n = 4";
where state = "Table lock" and info = "update low_priority t1 set n = 4";
--source include/wait_condition.inc
send
select n from t1;
@ -30,7 +30,7 @@ connection locker;
# Sleep a bit till the select of connection reader is in work and hangs
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info = "select n from t1";
where state = "Table lock" and info = "select n from t1";
--source include/wait_condition.inc
unlock tables;
connection writer;
@ -50,7 +50,7 @@ connection reader;
# Sleep a bit till the update of connection writer is in work and hangs
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info = "update low_priority t1 set n = 4";
where state = "Table lock" and info = "update low_priority t1 set n = 4";
--source include/wait_condition.inc
select n from t1;
connection locker;
@ -95,7 +95,7 @@ insert t1 select * from t2;
connection locker;
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info = "insert t1 select * from t2";
where state = "Table lock" and info = "insert t1 select * from t2";
--source include/wait_condition.inc
drop table t2;
connection reader;
@ -119,7 +119,7 @@ connection locker;
# Sleep a bit till the insert of connection reader is in work and hangs
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info = "insert t1 select * from t2";
where state = "Table lock" and info = "insert t1 select * from t2";
--source include/wait_condition.inc
drop table t2;
connection reader;
@ -163,8 +163,8 @@ SELECT user.Select_priv FROM user, db WHERE user.user = db.user LIMIT 1;
connection locker;
# Sleep a bit till the select of connection reader is in work and hangs
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info =
SELECT COUNT(*) = 1 FROM information_schema.processlist
WHERE state = "Table lock" AND info =
"SELECT user.Select_priv FROM user, db WHERE user.user = db.user LIMIT 1";
--source include/wait_condition.inc
# Make test case independent from earlier grants.
@ -298,7 +298,7 @@ connection reader;
# Wait till connection writer is blocked
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info = "alter table t1 auto_increment=0";
where state = "Table lock" and info = "alter table t1 auto_increment=0";
--source include/wait_condition.inc
send
alter table t1 auto_increment=0;
@ -306,7 +306,7 @@ connection locker;
# Wait till connection reader is blocked
let $wait_condition=
select count(*) = 2 from information_schema.processlist
where state = "Locked" and info = "alter table t1 auto_increment=0";
where state = "Table lock" and info = "alter table t1 auto_increment=0";
--source include/wait_condition.inc
unlock tables;
connection writer;
@ -461,16 +461,16 @@ update t1 set i= 10;
connection reader;
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info = "update t1 set i= 10";
where state = "Table lock" and info = "update t1 set i= 10";
--source include/wait_condition.inc
send
select * from t1;
connection default;
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info = "select * from t1";
where state = "Table lock" and info = "select * from t1";
--source include/wait_condition.inc
let $ID= `select id from information_schema.processlist where state = "Locked" and info = "update t1 set i= 10"`;
let $ID= `select id from information_schema.processlist where state = "Table lock" and info = "update t1 set i= 10"`;
--replace_result $ID ID
eval kill query $ID;
connection reader;
@ -613,11 +613,11 @@ lock tables t1 read;
let $tlwa= `show status like 'Table_locks_waited'`;
connect (waiter,localhost,root,,);
connection waiter;
--send insert into t1 values(1);
send insert into t1 values(1);
connection default;
let $wait_condition=
select count(*) = 1 from information_schema.processlist
where state = "Locked" and info = "insert into t1 values(1)";
where state = "Table lock" and info = "insert into t1 values(1)";
--source include/wait_condition.inc
let $tlwb= `show status like 'Table_locks_waited'`;
unlock tables;