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本篇內容主要講解“MySQL 的 RR 模式下死鎖”，感興趣的朋友不妨來看看。本文介紹的方法操作簡單快捷，實用性強。下面就讓丸趣 TV 小編來帶大家學習“MySQL 的 RR 模式下死鎖”吧!
一、問題提出
如下構造方式，問為什么 RC 模式下不會死鎖，RR 模式下死鎖。
drop table tt;
CREATE TABLE `tt` ( `id` int(11) NOT NULL, `c1` int(11) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `c1` (`c1`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into tt values(1,1);session 1session 2begin;
select * from tt where c1=1 for update;
update tt set id=2 where c1=1;
begin;select * from tt where c1=1 for update; 堵塞 select * from tt where c1=1 for update;
死鎖回滾二、分析方式首先分析 session 1 第一句：
select * from tt where c1=1 for update;
執行后的加鎖行為
RR
---TRANSACTION 231106, ACTIVE 9 sec3 lock struct(s), heap size 1160, 2 row lock(s)
MySQL thread id 11, OS thread handle 140737153623808, query id 303 localhost root
TABLE LOCK table `test`.`tt` trx id 231106 lock mode IX
RECORD LOCKS space id 127 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231106 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 0
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;
RECORD LOCKS space id 127 page no 3 n bits 72 index PRIMARY of table `test`.`tt` trx id 231106 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 4; compact format; info bits 0
0: len 4; hex 80000001; asc ;; 1: len 6; hex 0000000386c0; asc ;; 2: len 7; hex aa0000003f0110; asc ? ;; 3: len 4; hex 80000001; asc ;;RC
---TRANSACTION 231105, ACTIVE 7 sec3 lock struct(s), heap size 1160, 2 row lock(s)
MySQL thread id 11, OS thread handle 140737153623808, query id 295 localhost root
TABLE LOCK table `test`.`tt` trx id 231105 lock mode IX
RECORD LOCKS space id 127 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231105 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 0
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;
RECORD LOCKS space id 127 page no 3 n bits 72 index PRIMARY of table `test`.`tt` trx id 231105 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 4; compact format; info bits 0
0: len 4; hex 80000001; asc ;; 1: len 6; hex 0000000386c0; asc ;; 2: len 7; hex aa0000003f0110; asc ? ;; 3: len 4; hex 80000001; asc ;;我們可以看到因為 c1 是主鍵因此加鎖方式不管怎么樣都是 LOCK_X|LOCK_REC_NOT_GAP，主鍵上也是同樣的。就是鎖住了二級唯一索引和主鍵的相關記錄。
然后分析 session 1 第二句：
update tt set id=2 where c1=1;
執行后的加鎖行為
這一句比較重要，在二級唯一索引 c1 上會做一個刪除和插入操作，也就是會將原來的 1,1 記錄標記為 del flag，同時插入 2,1 這條記錄，這會引起一個鎖的繼承操作 (lock_rec_inherit_to_gap_if_gap_lock 調用會出現 GAP LOCK)，但是之前還會涉及到唯一性檢查因此還涉及到 LOCK_S 鎖和 next key lock 的存在 (對于二級索引做唯一性檢查始終是 next key lock)。這里的 del flag 也是形成死鎖的重要原因。(對于二級索引的 update 操作總是先刪除然后插入記錄，主鍵則會進行判斷是否可以容下新的記錄)
RR
---TRANSACTION 231106, ACTIVE 1626 sec5 lock struct(s), heap size 1160, 5 row lock(s), undo log entries 2MySQL thread id 11, OS thread handle 140737153623808, query id 305 localhost root
TABLE LOCK table `test`.`tt` trx id 231106 lock mode IX
RECORD LOCKS space id 127 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231106 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;
RECORD LOCKS space id 127 page no 3 n bits 72 index PRIMARY of table `test`.`tt` trx id 231106 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 4; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 6; hex 0000000386c2; asc ;; 2: len 7; hex 2c000000410dca; asc , A ;; 3: len 4; hex 80000001; asc ;;
RECORD LOCKS space id 127 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231106 lock mode S(LOCK_S) locks gap and rec(LOCK_ORDINARY[next_key_lock])
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
0: len 8; hex 73757072656d756d; asc supremum;;
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;
RECORD LOCKS space id 127 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231106 lock mode S(LOCK_S) locks gap before rec(LOCK_GAP)
Record lock, heap no 3 PHYSICAL RECORD: n_fields 2; compact format; info bits 0
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000002; asc ;;RC
5 lock struct(s), heap size 1160, 5 row lock(s), undo log entries 2MySQL thread id 11, OS thread handle 140737153623808, query id 316 localhost root
TABLE LOCK table `test`.`tt` trx id 231123 lock mode IX
RECORD LOCKS space id 128 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231123 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;
RECORD LOCKS space id 128 page no 3 n bits 72 index PRIMARY of table `test`.`tt` trx id 231123 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 4; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 6; hex 0000000386d3; asc ;; 2: len 7; hex 370000003206e2; asc 7 2 ;; 3: len 4; hex 80000001; asc ;;
RECORD LOCKS space id 128 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231123 lock mode S(LOCK_S) locks gap and rec(LOCK_ORDINARY[next_key_lock])
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
0: len 8; hex 73757072656d756d; asc supremum;;
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;
RECORD LOCKS space id 128 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231123 lock mode S(LOCK_S) locks gap before rec(LOCK_GAP)
Record lock, heap no 3 PHYSICAL RECORD: n_fields 2; compact format; info bits 0
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000002; asc ;;到這里 RR 和 RC 加鎖并沒有什么不同，因為都是唯一值，同時鎖繼承也都是二級索引上的都是 LOCK_S|LOCK_ORDINARY[next_key_lock]，但是下面就會出現不同了。
然后分析 session 2 的第一句：
select * from tt where c1=1 for update;
實際上這個時候存在 2 條 c1= 1 的記錄只有 1,1 標記為刪除了，1,2 沒有提交，都是需要訪問的。
然后堵塞行為為：
RR
LOCK WAIT 2 lock struct(s), heap size 1160, 1 row lock(s)
MySQL thread id 10, OS thread handle 140737153824512, query id 350 localhost root statistics
select * from tt where c1=1 for update
------- TRX HAS BEEN WAITING 11 SEC FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 129 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231146 lock_mode X(LOCK_X) locks gap and rec(LOCK_ORDINARY[next_key_lock]) waiting(LOCK_WAIT)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;RC
LOCK WAIT 2 lock struct(s), heap size 1160, 1 row lock(s)
MySQL thread id 10, OS thread handle 140737153824512, query id 325 localhost root statistics
select * from tt where c1=1 for update
------- TRX HAS BEEN WAITING 9 SEC FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 128 page no 4 n bits 72 index c1 of table `test`.`tt` trx id 231128 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP) waiting(LOCK_WAIT)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;我們這里可以看到對于 RR 模式下唯一鍵 c1 的 1,1 已經刪除了。我做了 debug 發現這里會在函數中 row_search_mvcc 加鎖前做判斷如下：
if (!set_also_gap_locks || srv_locks_unsafe_for_binlog || trx- isolation_level = TRX_ISO_READ_COMMITTED || (unique_search !rec_get_deleted_flag(rec, comp)) || dict_index_is_spatial(index)) {
goto no_gap_lock;
} else {
lock_type = LOCK_ORDINARY;
}我們拋開其他來分析這兩句
trx- isolation_level = TRX_ISO_READ_COMMITTED
如果是 RC 模式則直接上 LOCK_REC_NOT_GAP 及只鎖住記錄本身
(unique_search !rec_get_deleted_flag(rec, comp))
如果不是 RC，如果是二級唯一索引并且沒有被標記為 del flag 則標記為 LOCK_REC_NOT_GAP。但是如果標記為 del flag 則標記為 LOCK_ORDINARY 就是 next key lock。
分析 session 1 的最后一個語句也就是產生死鎖的語句：
select * from tt where c1=1 for update;
如上這個語句會訪問 1,1 標記為刪除了，1,2 沒有提交 的兩個記錄。這個時候就出現了不同。
RC
只需要唯一索引 1,1 上 LOCK_REC_NOT_GAP|LOCK_X 及記錄索引，這個鎖在本事物的第一句語句上已經獲得了，因此直接通過了，不需要做檢測。
RR
需要在唯一索引 1,1 上 LOCK_ORDINARY|LOCK_X 也就是就是 next key lock。這個鎖在本事物中并沒有獲取過，因此需要重新的檢測所的兼容性，最終加入了等待列表。
我們來看一下函數 lock_rec_lock_slow，我做 debug 的時候明顯看到了不同的邏輯：
if (lock_rec_has_expl(mode, block, heap_no, trx)) {
/* The trx already has a strong enough lock on rec: do 1,1 key lock RR NEX KEY LOCK stronager
nothing */
lock_rec_print(mode,block,heap_no,index,thr_get_trx(thr));
err = DB_SUCCESS;
} else { const lock_t* wait_for = lock_rec_other_has_conflicting( mode, block, heap_no, trx,index); if (wait_for != NULL) { /* If another transaction has a non-gap conflicting
request in the queue, as this transaction does not
have a lock strong enough already granted on the
record, we may have to wait. */
RecLock rec_lock(thr, index, block, heap_no, mode);
err = rec_lock.add_to_waitq(wait_for);
}三、總結
最終 RR 下形成了環路
session1 首先獲得唯一索引上的 1,1 記錄的 LOCK_REC_NOT_GAP|LOCK_X
然后 session 1 做 update 獲得唯一索引上的 1,1 記錄的 LOCK_ORDINARY(next key lock)|LOCK_S
然后 session 2 需要獲取唯一索引上的 1,1 記錄的 LOCK_ORDINARY(next key lock)|LOCK_X 發生等待
然后 session 1 需要獲取唯一索引上的 1,1 記錄的 LOCK_ORDINARY(next key lock)|LOCK_X 加入等待隊列進行等待
死鎖發生因此發生，而 RC 模式下最后兩部需要獲取的都是 LOCK_REC_NOT_GAP|LOCK_X，雖然 session 2 處于等待但是 session 因為已經獲得相同級別的鎖不會在進行檢測加鎖等待，而直接通過了。
下面是死鎖的記錄：
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 117 page no 4 n bits 72 index c1 of table `t1`.`tt` trx id 230530 lock_mode X(LOCK_X) locks gap and rec(LOCK_ORDINARY[next_key_lock]) waiting(LOCK_WAIT)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;
*** (2) TRANSACTION:
TRANSACTION 230525, ACTIVE 68 sec starting index read
mysql tables in use 1, locked 16 lock struct(s), heap size 1160, 6 row lock(s), undo log entries 2MySQL thread id 6, OS thread handle 140737153423104, query id 156 localhost root statistics
select * from tt where c1=1 for update
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 117 page no 4 n bits 72 index c1 of table `t1`.`tt` trx id 230525 lock_mode X(LOCK_X) locks rec but not gap(LOCK_REC_NOT_GAP)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;
*** (2) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 117 page no 4 n bits 72 index c1 of table `t1`.`tt` trx id 230525 lock_mode X(LOCK_X) locks gap and rec(LOCK_ORDINARY[next_key_lock]) waiting(LOCK_WAIT)
Record lock, heap no 2 PHYSICAL RECORD: n_fields 2; compact format; info bits 32
0: len 4; hex 80000001; asc ;; 1: len 4; hex 80000001; asc ;;
*** WE ROLL BACK TRANSACTION (1)四、棧幀參考
最后留下幾個棧幀以備分析使用
鎖繼承
#0 lock_rec_set_nth_bit (lock=0x30b1230, i=3) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/include/lock0priv.ic:91#1 0x0000000001a5d44a in RecLock::lock_alloc (trx=0x7fffd7803b10, index=0x7ffe7459ff80, mode=546, rec_id=..., size=9)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:1484#2 0x0000000001a5d826 in RecLock::create (this=0x7fffec0c0eb0, trx=0x7fffd7803b10, owns_trx_mutex=false, add_to_hash=true, prdt=0x0)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:1537#3 0x0000000001a5e60c in lock_rec_add_to_queue (type_mode=546, block=0x7fff9adb8150, heap_no=3, index=0x7ffe7459ff80, trx=0x7fffd7803b10,
caller_owns_trx_mutex=false) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:1853#4 0x0000000001a611ec in lock_rec_inherit_to_gap_if_gap_lock (block=0x7fff9adb8150, heir_heap_no=3, heap_no=1)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:2829#5 0x0000000001a62ea3 in lock_update_insert (block=0x7fff9adb8150, rec=0x7fff9b9c408c \200)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:3659#6 0x0000000001c53c25 in btr_cur_optimistic_insert (flags=0, cursor=0x7fffec0c23f0, offsets=0x7fffec0c24c8, heap=0x7fffec0c13e0, entry=0x7ffe7403bb70,
rec=0x7fffec0c24c0, big_rec=0x7fffec0c24b8, n_ext=0, thr=0x7ffe7403ba00, mtr=0x7fffec0c1bc0)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/btr/btr0cur.cc:3346#7 0x0000000001b195fe in row_ins_sec_index_entry_low (flags=0, mode=2, index=0x7ffe7459ff80, offsets_heap=0x7ffe7403bf98, heap=0x7ffe7403c448, entry=0x7ffe7403bb70,
trx_id=0, thr=0x7ffe7403ba00, dup_chk_only=false) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/row/row0ins.cc:3166#8 0x0000000001b1a15e in row_ins_sec_index_entry (index=0x7ffe7459ff80, entry=0x7ffe7403bb70, thr=0x7ffe7403ba00, dup_chk_only=false)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/row/row0ins.cc:3421#9 0x0000000001b9e053 in row_upd_sec_index_entry (node=0x7ffe7403b6f8, thr=0x7ffe7403ba00)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/row/row0upd.cc:2337#10 0x0000000001b9e1c3 in row_upd_sec_step (node=0x7ffe7403b6f8, thr=0x7ffe7403ba00)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/row/row0upd.cc:2364RR 加鎖 del flag 記錄
#0 lock_rec_set_nth_bit (lock=0x30b28b8, i=2) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/include/lock0priv.ic:91#1 0x0000000001a5d44a in RecLock::lock_alloc (trx=0x7fffd7804080, index=0x7ffe74064ea0, mode=259, rec_id=..., size=9)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:1484#2 0x0000000001a5d826 in RecLock::create (this=0x7fffec0c1e00, trx=0x7fffd7804080, owns_trx_mutex=true, add_to_hash=true, prdt=0x0)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:1537#3 0x0000000001a5e1c4 in RecLock::add_to_waitq (this=0x7fffec0c1e00, wait_for=0x30b0e58, prdt=0x0)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:1731#4 0x0000000001a5ee37 in lock_rec_lock_slow (impl=0, mode=3, block=0x7fff4d027b20, heap_no=2, index=0x7ffe74064ea0, thr=0x7ffe7459ff60)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:2004#5 0x0000000001a5f1ce in lock_rec_lock (impl=false, mode=3, block=0x7fff4d027b20, heap_no=2, index=0x7ffe74064ea0, thr=0x7ffe7459ff60)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:2082#6 0x0000000001a69a02 in lock_sec_rec_read_check_and_lock (flags=0, block=0x7fff4d027b20, rec=0x7fff4da8c07e \200 , index=0x7ffe74064ea0, offsets=0x7fffec0c2690,
mode=LOCK_X, gap_mode=0, thr=0x7ffe7459ff60) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:6457#7 0x0000000001b717f7 in sel_set_rec_lock (pcur=0x7ffe7459f6d0, rec=0x7fff4da8c07e \200 , index=0x7ffe74064ea0, offsets=0x7fffec0c2690, mode=3, type=0,
thr=0x7ffe7459ff60, mtr=0x7fffec0c2180) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/row/row0sel.cc:1270#8 0x0000000001b7ab6a in row_search_mvcc (buf=0x7ffe7405b9c0 \375\002 , mode=PAGE_CUR_GE, prebuilt=0x7ffe7459f4b0, match_mode=1, direction=0)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/row/row0sel.cc:5591RC 加鎖 del flag 記錄
#0 lock_rec_lock_slow (impl=0, mode=1027, block=0x7fff3310cdf0, heap_no=2, index=0x7ffe74076d90, thr=0x7ffe7459fc20)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:1962#1 0x0000000001a5f1ce in lock_rec_lock (impl=false, mode=1027, block=0x7fff3310cdf0, heap_no=2, index=0x7ffe74076d90, thr=0x7ffe7459fc20)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:2082#2 0x0000000001a69a02 in lock_sec_rec_read_check_and_lock (flags=0, block=0x7fff3310cdf0, rec=0x7fff33bdc07e \200 , index=0x7ffe74076d90, offsets=0x7fffec0c2690,
mode=LOCK_X, gap_mode=1024, thr=0x7ffe7459fc20) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/lock/lock0lock.cc:6457#3 0x0000000001b717f7 in sel_set_rec_lock (pcur=0x7ffe7459f6d0, rec=0x7fff33bdc07e \200 , index=0x7ffe74076d90, offsets=0x7fffec0c2690, mode=3, type=1024,
thr=0x7ffe7459fc20, mtr=0x7fffec0c2180) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/row/row0sel.cc:1270#4 0x0000000001b7ab6a in row_search_mvcc (buf=0x7ffe7403ae80 \375\002 , mode=PAGE_CUR_GE, prebuilt=0x7ffe7459f4b0, match_mode=1, direction=0)
at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/row/row0sel.cc:5591#5 0x00000000019d5493 in ha_innobase::index_read (this=0x7ffe7403cda0, buf=0x7ffe7403ae80 \375\002 , key_ptr=0x7ffe74095600 , key_len=5,
find_flag=HA_READ_KEY_EXACT) at /root/mysqlall/percona-server-locks-detail-5.7.22/storage/innobase/handler/ha_innodb.cc:9536#6 0x0000000000f934aa in handler::index_read_map (this=0x7ffe7403cda0, buf=0x7ffe7403ae80 \375\002 , key=0x7ffe74095600 , keypart_map=1,
find_flag=HA_READ_KEY_EXACT) at /root/mysqlall/percona-server-locks-detail-5.7.22/sql/handler.h:2942到此，相信大家對“MySQL 的 RR 模式下死鎖”有了更深的了解，不妨來實際操作一番吧！這里是丸趣 TV 網站，更多相關內容可以進入相關頻道進行查詢，關注我們，繼續學習！
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