MySQL数据库的一次死锁实例分析

-- 创建表test1 
CREATE TABLE test1 ( 
id int(11) NOT NULL AUTO_INCREMENT, 
name varchar(10) NOT NULL, 
PRIMARY KEY (id) 
); 
insert into test1 values('hello'); 
 
-- 创建表test2 
CREATE TABLE test2 ( 
id int(11) NOT NULL AUTO_INCREMENT, 
name varchar(10) NOT NULL, 
PRIMARY KEY (id) 
); 
 
-- Transcation 1 
begin; 
insert into test2 select * from test1 where id = 1; 
delete from test1 where id = 1; 
 
-- Transcation 2 
begin; 
insert into test2 select * from test1 where id = 1;

　　?***(1) TRANSACTION:

　　?TRANSACTION 0 677833455, ACTIVE 0 sec, process no 11393, OS thread id 278546 starting index read

　　?mysql tables in use 1, locked 1

　　?LOCK WAIT 3 lock struct(s), heap size 320

　　?MySQL thread id 83, query id 162348740 dcnet03 dcnet Searching rows for update

　　?update tab_test set state=1064,time=now() where state=1061 and time < date_sub(now(), INTERVAL 30 minute) (任务1的sql语句)

　　?***(1) WAITING FOR THIS LOCK TO BE GRANTED: (任务1等待的索引记录)

　　?RECORD LOCKS space id 0 page no 849384 n bits 208 index `PRIMARY` of table `db/tab_test` trx id 0 677833455 _mode X locks rec but not gap waiting

　　?Record lock, heap no 92 PHYSICAL RECORD: n_fields 11; compact format; info bits 0

　　?0: len 8; hex 800000000097629c; asc b ;; 1: len 6; hex 00002866eaee; asc (f ;; 2: len 7; hex 00000d40040110; asc @ ;; 3: len 8; hex 80000000000050b2; asc P ;; 4: len 8; hex 800000000000502a; asc P*;; 5: len 8; hex 8000000000005426; asc T&;; 6: len 8; hex 800012412c66d29c; asc A,f ;; 7: len 23; hex 75706c6f6164666972652e636f6d2f6 8616e642e706870; asc xxx.com/;; 8: len 8; hex 800000000000042b; asc +;; 9: len 4; hex 474bfa2b; asc GK +;; 10: len 8; hex 8000000000004e24; asc N$;;

　　?*** (2) TRANSACTION:

　　?TRANSACTION 0 677833454, ACTIVE 0 sec, process no 11397, OS thread id 344086 updating or deleting, thread declared inside InnoDB 499

　　?mysql tables in use 1, locked 1

　　?3 lock struct(s), heap size 320, undo log entries 1

　　?MySQL thread id 84, query id 162348739 dcnet03 dcnet Updating update tab_test set state=1067,time=now () where id in (9921180) (任务2的sql语句)

　　?*** (2) HOLDS THE LOCK(S): (任务2已获得的锁)

　　?RECORD LOCKS space id 0 page no 849384 n bits 208 index `PRIMARY` of table `db/tab_test` trx id 0 677833454 lock_mode X locks rec but not gap

　　?Record lock, heap no 92 PHYSICAL RECORD: n_fields 11; compact format; info bits 0

　　?0: len 8; hex 800000000097629c; asc b ;; 1: len 6; hex 00002866eaee; asc (f ;; 2: len 7; hex 00000d40040110; asc @ ;; 3: len 8; hex 80000000000050b2; asc P ;; 4: len 8; hex 800000000000502a; asc P*;; 5: len 8; hex 8000000000005426; asc T&;; 6: len 8; hex 800012412c66d29c; asc A,f ;; 7: len 23; hex 75706c6f6164666972652e636f6d2f6 8616e642e706870; asc uploadfire.com/hand.php;; 8: len 8; hex 800000000000042b; asc +;; 9: len 4; hex 474bfa2b; asc GK +;; 10: len 8; hex 8000000000004e24; asc N$;;

　　?*** (2) WAITING FOR THIS LOCK TO BE GRANTED: (任务2等待的锁)

　　?RECORD LOCKS space id 0 page no 843102 n bits 600 index `idx_1` of table `db/tab_test` trx id 0 677833454 lock_mode X locks rec but not gap waiting

　　?Record lock, heap no 395 PHYSICAL RECORD: n_fields 3; compact format; info bits 0

　　?0: len 8; hex 8000000000000425; asc %;; 1: len 8; hex 800012412c66d29c; asc A,f ;; 2: len 8; hex 800000000097629c; asc b ;;

　　?*** WE ROLL BACK TRANSACTION (1)

　　?(回滚了任务1，以解除死锁)

　　select id from tab_test where state=1061 and time < date_sub(now(), INTERVAL 30 minute);

　　update tab_test state=1064,time=now() where id in(......);